Posted By Michael Savage, Sr.,
Tuesday, November 19, 2013
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Not too many years ago, I was conversing with a friend of mine, who is also an electrical inspector, about which codes and standards apply to electrical inspectors and, for that matter, any construction inspector during the course of their appointed duties. During our rather lively discussion, he mentioned that his supervisor, who is a building code administrator, believed electrical inspectors were liberated from having to comply with NFPA 70E. One can speculate about the reasons, although many of us can surely see the potential budget expenses of getting all the inspectors on one’s staff certified to inspect equipment "hot.” My friend and I ended our conversation with my promising to commit a future article to these ponderings…. I guess it is never too late!
The 2012 edition of the Standard for Electrical Safety in the Workplace states under Section 90.1 Purpose, "The purpose of this standard is to provide a practical safe working area for employees relative to the hazards arising from the use of electricity.”
Additionally, the document states under Section 90.2 Scope.
"(A) Covered. This standard addresses electrical safety related work practices for employee workplaces that are necessary for the practical safeguarding of employees relative to the hazards associated with electrical energy during activities such as the installation, inspection, operation, maintenance, and demolition of electric conductors, electric equipment, signaling and communications conductors and equipment, and raceways. This standard also includes safe work practices for employees performing other work activities that can expose them to electrical hazards as well as safe work practices for the following:
(1) Installation of conductors and equipment that connect to the supply of electricity
(2) Installations used by the electric utility, such as office buildings, warehouses, garages, machine shops, and recreational buildings that are not an integral part of a generating plant, substation, or control center.”
The 2012 edition added the term inspection in its scope. This will certainly answer the question about whether or not 70E applies to electrical inspectors in the workplace. The next question is what does that mean? Let’s look at the responsibility of the employer versus the employee. Section 105.3 Responsibility, states "the employer shall provide the safety-related work practices and shall train the employee, who shall then implement them.” Therefore, it is the responsibility of the employer to provide the safety-related work practices. As such, 70E provides for a host of training requirements within its text, including training for Qualified Persons, Unqualified Persons, Host Employer Responsibilities, Contract Employer Responsibilities, Documentation and Retraining.
As Jeffrey Sargent said in his article from the NFPA Journal, May/June 2010 entitled, "A glimpse of the proposed changes for the 2012 edition of NFPA 70E”: "The world of workplace electrical safety is rapidly evolving, in large part due to the increased awareness and implementation of NFPA 70E®, Electrical Safety in the Workplace®, in the last decade.” With the introduction of newer technologies and equipment for addressing hazards, as well as, a better understanding and training about electrical hazards, workers can be kept safe (yes, even the electrical inspector). OSHA, under the Code of Federal Regulations (CFR), is responsible for the provision for working safely with electricity; and NFPA 70E shows you how to do it properly. I, personally, do not want our staff to open any high voltage equipment without it being de-energized first. Without the specific training to recognize those hazards — and I’m not talking about "knowing enough to be dangerous” — I prefer for the system to be de-energized.
So the next time you hear a statement that it "doesn’t apply” to you as an inspector, stop and contemplate that statement a moment. If you are uncertain, then ask yourself one question: Am I Superman? Because as far as I know, he is the only one who can withstand high voltage unharmed!
We’ll save the provisions of CFR 1910 and 1926 for next time. E-mail your comments to email@example.com.
Jeffrey Sargent, NFPA Journal, May/June 2010
Posted By Steve Foran,
Tuesday, November 19, 2013
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You must have very clear rules that apply to procedures related to safety.
For example, at our electric utility there was a policy governing when customers requested power turned on (which we did at the meter) that they must be home at the time power is connected. No exceptions. The spirit behind this policy was to prevent an accident such as a fire caused by a box left on an electric stovetop that had an element turned "on” and inadvertently left "on” when the premises were without power.
If the customers were not there to ensure the premises were safe, the power would stay off even if the service rep could see through a window that the stove was clear – because other hazards could be created by energizing the home.
However, when it comes to creating service guidelines unrelated to safety, you must be creative in allowing exceptions or you risk increased costs, dissatisfied customers, and disengaged employees who feel powerless.
Earlier this year I was away with a group of friends. At the end of the weekend, as we were heading for home, one of my friends had a problem with the automatic opening device on his gas tank. The mechanism was jammed closed, and he could not fill his tank – not a drop. He had little gas in his tank; and although his car worked fine, if he headed out on the highway he quickly would be stranded in the middle of nowhere.
Fortunately, his vehicle was relatively new and covered by the manufacturer’s roadside assistance program. The agent he spoke with was very helpful. It was not going to cost my friend anything to get the problem repaired, and the program’s trip interruption insurance would cover his expenses to stay an extra night because he was away from home and the dealership was closed until the next day.
They finalized the plans to get the vehicle repaired, and then my friend said, "I’ll drop the car at the dealership and one of my friends can drive me to the hotel.” The agent replied, "Well, if you want the trip interruption insurance to pay your accommodation expenses, your car needs to be towed to the dealership.”
My friend explained that the dealership was less than half a mile up the road. The agent said that there was no way he could make an exception. My friend reluctantly agreed and the agent arranged for a tow-truck. It was supposed to arrive in 20 minutes, but it took more than an hour.
When the tow truck arrived, my friend explained the situation to the driver. The driver jumped back in his truck and said, "Follow me.” Three minutes later, they pulled into the dealership; my friend left his keys in the key drop; we drove him to his hotel and then we headed for home. His car was repaired first thing the next morning, and he was home by noon.
Here, we see a procedural code that when enforced, ended up costing the car manufacturer more, causing more inconvenience to the customer, and probably frustrating the agent because he had no freedom to exercise his judgment. The only beneficiary was the tow truck company and driver, which in this case I suspect got paid for simply showing up, rather than for performing a tow.
Clearly, in spite of the legitimate claim made by my friend, not towing his vehicle went against the manufacturer’s policy but it eliminated the time and effort to tow the vehicle as well as any risk associated with moving the vehicle. The agent should have had the authority to assess the situation and been empowered to make an exception.
To prevent service failures from happening in your organization, you need to monitor service delivery and identify the policies and procedures that rob people of their ability to think and that relegate them to a job of service mediocrity.
Monitoring is simple. Set up a system to follow up with customers and ask them two questions, "What did you like best about the service we provided?” and, "What did you like least about the service we provided?”
Then use their feedback to improve how you serve.
Read more by Steve Foran
Posted By Underwriters Laboratories,
Tuesday, November 19, 2013
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We’re struggling to find listed air compressors, does UL List (certify) air compressors?
Yes, UL certifies (Lists) air compressors under the product category Compressors, Vacuum Pumps and Pneumatic Paint Sprayers (QDGS), located on page 330 in the 2013 UL White Book. By accessing UL’s Online Certifications Directory at www.ul.com/database and entering QDGS at the category code search field, you can access the nearly 60 manufacturers that have certification under this category.
This category covers air compressors and vacuum pumps, including pneumatic-type paint sprayers rated 600 volts or less.
Products can be cord-connected or provided with means for permanent connection in the field. Permanently connected products are intended to be installed in accordance with ANSI/NFPA 70, National Electrical Code (NEC).
The basic standard used to investigate products in this category is ANSI/UL 1450, the Standard for Safety for Motor-Operated Air Compressors, Vacuum Pumps, and Painting Equipment.
If there is an uncertified compressor that is already installed in the field, UL can conduct a field evaluation on the compressor. For more information on field evaluations, or to schedule a field evaluation, call 877-ULHELPS (877-854-3577) or request this online at www.ul.com/field.
Article 502 in the NEC permits electrical metallic tubing (EMT) as a wiring method in Class II, Division 2 hazardous classified locations provided the fittings are dust tight. The contractor wants to use certified (Listed) compression type EMT fittings suitable as rain tight. Are EMT fittings certified for use as "rain tight” also dust tight? Are there any certified dust tight EMT connectors?
EMT connectors that arecertified (Listed) as rain tight are certified for use in wet locations and not additionally evaluated as dust tight, there is no correlation between the two ratings. EMT fittings are certified under the product category Electrical Metallic Tubing Fittings (FKAV), located on page 151 in the 2013 UL White Book and also on UL’s Online Certifications Directory at www.ul.com/database and enter FKAV at the category code search field.
The Guide Information for FKAV states that fittings suitable for use where exposed to rain are so indicated on the device or carton. The terms "rain tight,” "wet location”or the equivalent on the carton indicates suitability for use where directly exposed to rain.
Consequently, there are no EMT fittings that are rated as dust tight, Type 4 or Type 4X. If EMT fittings were submitted for such a rating, UL would consider developing/expanding certification requirements, as necessary, for these type of fittings for use with EMT just as UL can currently evaluate EMT fittings for use with enclosures for other environments, in accordance with UL 514B, the Standard for Safety for Conduit, Tubing, and Cable Fittings.
I have encountered the installation of ceiling-mounted LCD or DLP projectors in suspended ceilings. From my perspective, NEC 400.8(5) would not allow a cord to be located above a suspended ceiling. Does UL certify (List) permanently mounted projectors, or any projectors in which the cord is located above the ceiling and permanently wired into a box?
No, UL does not certify (List) flexible cord connected projectors to be installed above a ceiling. LCD and DLP projectors are certified (Listed) under the product category Information Technology Equipment Including Electrical Business Equipment (NWGQ), located on page 277 in the 2013 UL White Book or on UL’s Online Certifications Directory at www.ul.com/database and enter NWGQ at the category code search field. Certified projectors would be certified to be installed in accordance with the NEC which prohibits flexible cords installed above or through a suspended ceiling.
Read more by UL
UL Question Corner
Posted By Ark Tsisserev,
Tuesday, November 19, 2013
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No, really: what codes and standards must be used for the electrical design and installation and why?
This is not a trivial question, as it deals with consistency, uniformity and, most important, with the safety of electrical installations.
So, what drives a need to use the CE Code (and not the NEC) for design of electrical installations in Canada, and what forces the designers to specify, for example, an automatic transfer switch to the CSA standard CSA C22.2 No. 178.1 and not to the UL standard UL1008? Why, for instance, is ULC S524 (and not NFPA 72) used by the designers, installers and regulators for the selection of locations of and spacing between the fire alarm system devices?
The answer is based on the provisions of the Canadian Electrical Safety System, the unique entity which integrates development of safety standards for electrical products with the electrical equipment design, construction, testing and certification to these safety standards, and with installation of the "approved” electrical equipment in accordance with the requirements of the installation code — the CE Code, Part I. Such integration is done under the electrical safety regulatory regime that is administered consistently across the country at each provincial or territorial level.
Photo 1. Wiring methods – See section 12 of the CE Code.
Nevertheless, an inquisitive mind might comment that any safety standard for electrical equipment or even the mighty electrical installation code is only a voluntary standard. This observation would be absolutely accurate — until the time when the Code or the specific standard is legally adopted in each jurisdiction for the regulatory enforcement. When this adoption is done, the Code or the standard becomes the law, and use of such code or standard (and compliance with it) becomes mandatory.
In fact, the very first statement in the Code (shown in the rectangular box on the first page of the Code) indicates that, "The Canadian Electrical Code, Part I, is a voluntary code for adoption and enforcement by regulatory authorities.”
This means that until the Code is legally adopted for enforcement purposes, it is not different from any other publication available on the marketplace. A major difference of this document from many other available publications is that this document (and any safety standard for electrical equipment) is being developed via a consensus process by participating experts who represent all areas of the electrical safety (i.e., manufacturers, designers, contractors, educators, power and communication utilities, labour, installation users, etc.) In fact, the CE Code and safety standards for electrical products are specifically intended to be legally adopted for enforcement, as the electrical safety regulators from every provincial and territorial jurisdiction play a major role in the development of these documents. The CE Code development process includes a transparent means by which participating regulators indicate whether they might have regulatory issues with the proposed language of the Code, and whether such legal issues would adversely impact their ability to administer the Code. This process helps to resolve such issues at the code development stage in order to facilitate the future Code adoption process. This explains why only the CE Code is used as the safety standard for electrical installations.
When the Canadian Electrical Code is legally adopted in a specific jurisdiction, only this adopted Code (and not the NEC or any other electrical installation code or standard) must be used by the industry stakeholders. This means that if, for example, C22.2 No. 178.1 is referenced in the body of the legally adopted CE Code(i.e., Rule 24-304), then only this CSA standard must be used for the design, construction, testing and certification of an automatic transfer switch (and not UL 1008 or any other similar standard).
Photo 2. Installation – as per Section 24 of the CE Code, electrical safety in health care facilities – as per Z32But what about the standard ULC S524 for installation of a fire alarm system devices? Is this ULC standard specifically mandated by the CE Code? Although use of the ULC S524 is only referenced in an explanatory (non-mandatory) Appendix B Note on Section 32 of the Code, compliance with this ULC standard is mandatory, as use of this standard is required by the National Building Code of Canada (NBCC ),which is also legally adopted in each province and territory. Sentence 220.127.116.11.(1) of the NBCC states that "Fire alarm systems, including the voice communication capability where provided, shall be installed in conformance with CAN/ULC-S524, ‘Installation of Fire Alarm Systems.’ ” There are some other cases, when use of a particular standard is only mentioned in Appendix B Notes on the CE Code, but is mandated by specific provisions of the NBCC. One such example is the CSA standard B72 "Installation Code for Lightning Protection System.” While it is not mandated for use by the CE Code (it is only referenced in Appendix B Note on Rule 10-706), its use is required by Article 18.104.22.168. of the NBCC. This means that when a lightning protection system is designed for use in Canada, it must comply with the CSA standard B72.
Similarly, use of the CSA B44 "Safety Code for Elevators and Escalators” is mandated by the NBCC, but is only referenced in a non-mandatory Appendix B Notes on Rules of Section 38 in the CE Code. Sometimes, certain standards are referenced only in explanatory Appendix B of the CE Code and not in the body of the code, and use of these standards is also not required by the NBCC. In these cases, application of such standards is not mandatory under provisions of the CE Code, and their reference is only intended to the code users for informational purpose. For example, Appendix B notes on Rules 2-304 and 2-306 reference CSA standard Z462. However, there is no need for the Code users to apply this standard during design and installation of electrical equipment, as this standard is only intended for safe work practices around energized electrical equipment in conjunction with the local occupational health and safety regulations (if it is legally adopted by these work health and safety jurisdictions). Otherwise, Z462 is a voluntary standard, and use of this standard is a good engineering practice.
Photo 3. Installation – as per Section 58 of the CE Code, safety of aerial tramways – as per Z98Another such example: ANSI standard B77.1 or CSA standard Z98. Compliance with ANSI standard B77.1 "Passenger Ropeways – Aerial Tramways, Aerial Lifts, Surface Lifts, Tows and Conveyors – Safety Requirements” and CSA standard Z98 "Passenger Ropeways and Passenger Conveyors” is not considered to be mandatory, as these standards are only referenced for information purpose in non-mandatory Appendix B Note on Section 58.
It is interesting to note that occasionally legally adopted building and electrical codes reference different editions of certain standards. In this case, the latest edition should be used, as it accurately reflects the latest consensus based revisions to such documents. For example, 2010 edition of the NBCC references C282-05 and Z32-04. However, 2012 edition of the CE Code mandates use of both these standards in the body of the Code and references 2009 editions of each of these standards.
And what about various IEEE or NFPA standards? Are they mandated by the legally adopted CE Code or the NBCC?
IEEE is a purely electrical engineering standard, and it is not referenced by the NBCC. The CE Code, however, mandates use of IEEE 835 (see Rule 4-004) and of IEEE 80 (see Tables 51 and 52 of the CE Code). Other IEEE standards are utilized by many designers as a part of a good engineering practice or as a part of requirements of the system performance, but not as the electrical safety requirement in accordance with the CE Code. Many NFPA standards are mandated by the NBCC, and the electrical professionals involved in design of electrically connected life safety systems in accordance with such standards must use these standards accordingly. Examples of NFPA 13, NFPA 20, NFPA 80, NFPA 96 is a case in point for a need to apply these technical documents by the electrical design professionals.
And, of course, compliance with the CSA engineering standards C22.3 No. 1 and C22.3 No. 7 is mandatory, as use of these standards is required by the CE Code.
There are quite a few examples of a similar nature, but the fundamental principle is based on understanding the difference between mandatory and voluntary standards. If use of the former is required by law, the application of latter is a demonstration of a good engineering practice in order to enhance performance of the designed electrical systems or to meet specific requirements of the owners or operators of the facility subjected to the electrical design.
Photo 4. Installation of a strobe light – as per ULC S524, wiring methods – as per Section 32 of the CE Code.
And last, but not least, we need to discuss a compliance with various safety standards for electrical equipment. Quite often electrical design specifications reference NEMA, EEMAC or UL standards for electrical products. However, such practice is not consistent with provisions of Rule 2-024 of the CE Code.
All electrical equipment installed in accordance with the CE Code must be "approved” as required by Rule 2-024 of the CE Code.
Rule 2-024 states the following, "Electrical equipment used in electrical installations within the jurisdiction of the inspection department shall be approved and shall be of a kind or type and rating approved for the specific purpose for which it is to be employed.”
It should be noted that approved is a defined term in the CE Code, and it means that the electrical equipment is certified by an accredited certification organization to the provisions of an applicable CSA safety standard (CSA Part II standard – one of the safety standards for electrical products listed in Appendix A to the CE Code, starting on page 376 of the CE Code 2012). The CE Code defines approvedequipment as follows:
"Approved (as applied to electrical equipment) —
(a) equipment that has been certified by a certification organization accredited by the Standards Council of Canada in accordance with the requirements of
(i) CSA standards; or
(ii) other recognized documents, where such CSA standards do not exist or are not applicable; or
(b) equipment that conforms to the requirements of the regulatory authority (see Appendix B).
Appendix B Note on definition "approved” states:
"It is intended by this definition that electrical equipment installed under provisions of this Code is required to be certified to the applicable CSA product Standards as listed in Appendix A. Where such CSA Standards do not exist or are not applicable, it is intended by this definition that such electrical equipment be certified to other applicable Standards, such as ULC standards. Code users should be aware that fire alarm system equipment is deemed to be approved when it is certified to the applicable product Standards listed in CAN/ULC S524.
"This definition is also intended to reflect the fact that equipment approval could be accomplished via a field evaluation procedure in conformance with the CSA Model Code SPE-1000, where special inspection bodies are recognized by participating provincial and territorial authorities having jurisdiction. For new products that are not available at the time this Code is adopted, the authority having jurisdiction may permit the use of products that comply with the requirements set out by that jurisdiction.”
The Standards Council of Canada has accredited a number of certification organizations (CSA, UL, ULC, ETL, QPS, etc.) to certify electrical products to the CSA (CE Code, Part II) safety standards. When the piece of electrical equipment is certified by the CSA, then "CSA” monogram must be placed on that piece of electrical product in accordance with Rule 2-100 of the CE Code. When the piece of electrical equipment is certified by the UL (US-based certification organization), then the certification monogram by UL must also bear a small "c” at 8 o’clock. This "c” signifies that the piece of electrical equipment is certified by the UL for use in Canada to the CSA standard. For example, if a luminaire is marked "cUL,” it means that the UL certified this luminaire to the CSA standard C22.2 No. 250"Luminaires” (see page 381 of the CE Code 2012). If an automatic transfer switch (see our example above) is certified by UL for use in Canada, the "cUL” monogram will signify that such automatic transfer switch is certified by the UL to the CSA safety standard C22.2 No. 178.1 listed on page 379 of the CE Code 2012 (and not to the standard UL 1008 for the automatic transfer switches).
Certification to a UL, NEMA, EEMAC or IEEE standard does not make such equipment "approved” for use in Canada under Rules of the CE Code.
When a piece of a fire alarm system equipment (a control unit, a smoke detector, a manual station, etc.) is certified to the applicable ULC safety standard listed in the ULC 524, such piece of equipment is deemed to be "approved’ in accordance with the CE Codedefinition, as there are no CSA safety standards available for such products. In this case, a "ULC” monogram on such piece of equipment would manifest the fact that that particular piece of a fire alarm equipment is certified by the ULC to the applicable ULC safety standard for fire alarm systems. For example, if a control unit of a fire alarm system bears the "ULC” monogram, it means that the control unit is certified by the ULC to the ULC standard ULC S527 "Control Units for Fire Alarm Systems.”
It should be noted that in accordance with the CE Code definition of "approved,” a piece of electrical equipment may be also approved by means of a special inspection/field evaluation. This type of approval does not constitute a complete certification to any applicable CSA safety standard referenced in Appendix A of the Code. Such field evaluation represents only testing in accordance with the scope of the CSA Model Code for Field Evaluation of Electrical Equipment SPE 1000.
Specific conditions of every field evaluation should always be discussed with the local electrical safety authority.
Hopefully, this brief article helps in clarifying the subject related to the criteria for use of Codes and standards in electrical design and installations.
Read more by Ark Tsisserev
Posted By Pete Jackson,
Tuesday, November 19, 2013
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We all have
a unique perspective based upon our life experience. No two people have lived
the same life and, therefore, do not have the same perspective. Your
perspective is what sets you apart from all others and will define the value
you add to the industry. Our knowledge, both technical and code, gained through
formal education, work experience, and training is extremely valuable; but
there is more: there is the human element. Your perspective is shaped by life
experiences beyond the technical.
How do we interact with people? What does the NEC
say? What does it mean? How do we convey its objective to others? Communication
and enforcement of code requirements in a way that others will understand and
appreciate are the challenge. Meeting that challenge defines our value to the
Knowing the reason for a code requirement is key to
understanding it. As I type this article, I cannot help but remember the
required typing class that I took as a senior (I put it off as long as I could
do so.) in high school — the one that seemed to serve no purpose at the time!
We often do not appreciate the importance of knowledge or a skill without the
benefit of future experience.
We have all come from different backgrounds. Everyone
has strengths and weaknesses both technical and personal. We should strive to
use our strengths (and share them with others) and improve in the areas where
needed. No one knows it all. No one has done it all. Arrogance is the greatest
Some of us have worked for, or as, contractors and
bring that perspective to work as inspectors. We have lived through the fears
and concerns of the installer/small business owner and learned to appreciate
the value of code-compliant installations for both the owner and installer. We
know, firsthand, the importance of the level playing field that fair consistent
inspections provide for the marketplace. We know that correct installations do
not have to cost more or take longer than incorrect installations. The
opposite is usually the case.
As inspectors, we
know the political and practical pressures faced by jurisdictions. We are aware
of the conflicting interests involved. We have also had to face the challenge
of the most recent economic downturn. The economy may slow and new construction
fall off, but the code must still be enforced. We end up with fewer resources,
but we do not necessarily have fewer code violations. So we learn to do more
inspections with less. The cost of new code rules must always be appreciated,
but we cannot forget that burning buildings are not good for business either.
Although there is no substitute for proper
code/technical knowledge there are other qualities that, as inspectors, we must
Credibility is our most valuable asset and the
essence of what we do for a living. Our "yes” must be "yes,” and our "no”
should mean "no.” When we do not know something, we should say so, and then
find the answer. If we are dealing with a grey code area, we must not forget
the big picture and seek consistency. Our decisions will have life safety and
financial consequences. The truth will always come out at some point, so why
not start with it? Without integrity, our performance, no matter how well it
may be, is meaningless. With integrity, even our mistakes are not a weakness
because there is no intent to conceal.
Consistency is a key element of quality.
Perfection can be the enemy. It is better to aim for a consistent, attainable
standard than to accept an unrealistic standard that is never met. Can
perfection be defined to the satisfaction of all in any realm of life or work?
We are never perfect, and there is always a better way to perform a task. We
only fail when we do not seek a better way or learn from a mistake. Mistakes
are only failures when we choose to ignore the lesson. Something will be missed
at every inspection by even the best inspector. There is so much to inspect and
so little time available. Combination inspectors, in particular, have a heavy
load. The perfect inspection should not be the goal; due diligence should be
the goal. Do we know the key code requirements in play for the phase of the
project? Are we calling something at final inspection that should have been
found during the rough inspection, such as an incorrect wiring method? Are we
measuring the distance between conduit straps without realizing that the wiring
method used was not permitted for the occupancy? We can be limited by our
abilities or by the limitations imposed on us through the political realities
of life; but whatever our limitations, we must always seek to provide
knowledgeable consistent inspections.
Good judgment is the most important quality for
an inspector. Training and experience are the prerequisites for a mature
approach. Applying judgment to the infinite situations encountered is what I
enjoy the most about the inspection process. We are often dealing with a very
grey world and attempting to make it as black and white as possible. The
purpose of the NEC is the practical safeguarding of persons/property
from hazards arising from the use of electricity (NEC 90.1). Applying
the code correctly with the proper balance for all concerned is the greatest
challenge and the most rewarding part of the job.
Disagreement and conflict are a normal part of
an inspector’s job. How we handle conflict will define our ability as an
inspector. We should never seek to cause conflict, but we must be aware that
conflict is a natural component of the inspection process. Conflict should be a
healthy constructive element of life.
Conflict should not equate to anger or loss of control. Honest
confrontation of differing opinions or competing ideas will result in a
stronger product. Often, more damage is done when people seek to avoid
conflict. The result of sticking our head in the sand is worse than facing the actual
conflict itself. I like to use this example; if your car has a flat tire, it
does not help to change the fan belt. The tire must be changed! Quite often, in
work situations, I see people (or committees) avoid conflict by changing the
fan belt, when it is the tire that is flat. The other destructive approach to
conflict is the assumption of only two solutions to a problem. There are always
multiple solutions to every problem, and we must find the best solution for a
given situation. How to handle conflict? Embrace it!
As inspectors we may have come from different
backgrounds; yet, as IAEI members, we are all in the same place now. IAEI
membership provides a forum for sharing our strengths and improving our
abilities. More importantly, IAEI is our voice for sharing the collective
inspector perspective with the industry we serve. As inspectors, we know that proper electrical
connections are vital to the long-term success of every electrical system. The
IAEI connection to each other and to industry is just as beneficial to the
long-term success of all.
Read more by Pete Jackson
Posted By Steve Douglas,
Tuesday, November 19, 2013
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You attend great meetings? For opportunities to meet other inspectors? For networking? For excellent technical training opportunities? These are great reasons, but there may be more to consider.
I was surprised to learn how much more IAEI had to offer.
In my second year as a wiring inspector, I was introduced to IAEI; the year was 1991 and the event was the Canadian Section meeting held in Kingston, Ontario. I was able to meet inspectors from all over Ontario, Canada, and the United States. The training offered by leading experts was second to none, and the social programs for both the delegates and partners were very impressive. My thought was…… WOW, I need to be a part of this! I left the meeting with an idea of what I thought IAEI was. It was not until years later and after being involved in codes and standards development that I got a better appreciation of the important role IAEI plays in the electrical safety infrastructure for both our great nations.
IAEI and the National Electrical Code
IAEI was established in 1928, and in the same year was represented on the National Electrical Code. Involvement in code development evolved in the following 85 years. IAEI was first represented on all the National Electrical Code (NEC) code-making panels (CMP) in the 1971 edition. Prior to IAEI’s involvement in the NECdevelopment process, enforcers did not have a common voice on the development of the NEC. With the large number of authorities having jurisdiction in the United States and the limited number of enforcer positions on the code-making panels, it is impossible for all authorities having jurisdiction individually to have a voice on the development of the NEC. IAEI provides this voice for authorities having jurisdiction with a focus on:
Enforceability. Will an electrical inspector be able to enforce the requirement if it is adopted by the authority having jurisdiction?
Reasonability.The object of the Code is "to establish safety standards for the installation and maintenance of electrical equipment…” While the cost of complying with the Code is not a criterion for an inspector to decide upon support of a concept, the Coderequirement should be practical.
Understandability. Complex and lengthy sentences and paragraphs are difficult to read, understand, and enforce. Making the Code clearer is an objective of IAEI code panel members.
Members of the code-making panels also provide the vital information to IAEI International for development of great technical books such as the Analysis of Change. Now that I am on that topic, I would like to thank the international office and in particular Keith Lofland for the outstanding work in development of this world class publication.
IAEI and the Canadian Electrical Code
In the early 1980s Roy Hicks the Chief Inspector of Ontario Hydro Electrical Inspection recognized a need for front line involvement in the development of the CE Code. Roy had seen the IAEI as the vehicle to achieve this.
IAEI involvement in the Canadian Electrical Code began during the development of the 1986 edition with members on several subcommittees. By the 1998 edition, IAEI had representation on nine subcommittees and an associate member on the CE Code Part I. The associate member position on Part I evolved into a full voting member of the CE Code Part I during the development of the 2006 edition. At the publication of the 2009 CE Code, IAEI had representation on all 43 sections, being the first organization to have representation on all sections of the CE Code since the first edition dated 1927.
Where would the electrical industry be without IAEI?
Codes and standards committees would not have a common voice representing authorities having jurisdictions, and would be relying on individuals providing inspector input without a national or international focus.
We would not have an organization watching for initiatives that may erode our present electrical safety infrastructure.
As an example, an installation standard developed in Canada known as the Objective Based Industrial Electrical Code mayhave had a significant impact on authority having jurisdiction involvement on installations and facilities utilizing the Objective Based Industrial Electrical Code. The original intent of the Objective Based Industrial Electrical Code was to allow designers to develop their own installation and product requirements. This would mean no nationally developed electrical code or product standards, resulting in installations not meeting the minimum safety objectives of the electrical code, and the use of electrical products that are not certified. As a direct result of involvement of IAEI and the International Public Affairs Committee, the Objective Based Industrial Electrical Code ended up as a completely different document. Installations following the Objective Based Industrial Electrical Code are first required to meet the minimum requirements of the Canadian Electrical Code Part I. If the CE Code does not cover the particular installation, the designer can utilize the NEC. If the NEC does not cover the particular installation, the designer can utilize a recognized world standard; and if none of these cover the particular installation, the designer can develop his own installation requirements, provided the fundamental safety objectives of the code are not compromised.
Electrical products following the Objective Based Industrial Electrical Code are first required to be certified or approved to a recognized Canadian Standard. If a recognized Canadian Standard does not exist for the particular electrical product, the designer can utilize a recognized standard from the United States. If a recognized standard from the United States does not exist for the particular electrical equipment, the designer can utilize a recognized world standard, and if none of these cover the particular electrical equipment, the designer can develop his own product requirements.
As you can see, IAEI involvement on this one installation document alone has had a significant impact on the final requirements. If IAEI were not involved and the standards were developed as originally intended, the next step would have been to use the Objective Based Industrial Electrical Code as a seed document to develop similar requirements in the United States, resulting in a potential erosion of existing electrical safety infrastructure and the need for many authority having jurisdiction inspectors.
Another example IAEI is watching closely is inspection involvement with new technologies, such as photovoltaic, wind turbines and electric vehicles.
In total, IAEI presently has 156 member positions filled on codes and standards committees in the United States and Canada.
We have tremendous talent representing IAEI on codes and standards committees, but we need more. We need more inspectors just like you to step forward and get involved with theNEC and product standards development. Your experience and knowledge are invaluable on these committees. If you are interested in being part of a code or standards committee, please send your application in as soon as possible. Application forms are available online at IAEI.org under the "About Us” and "Code Panel Representatives” tab.
Now, back to the original question: Why are you an IAEI member?
I am an IAEI member because I want to be part of an organization that has such a positive impact on the electrical safety infrastructure in North America, providing premier education, certification of inspectors, and expert leadership in Electrical Codes and Standards development.
Read more by Steve Douglas
Posted By Randy Hunter,
Tuesday, November 19, 2013
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We have finally reached the portion of the code
that deals with conductors. Conductors are used on every electrical
installation, so naturally we have a variety of installation conditions and a
wide range of applications. Again, keeping to the scope of work for combination
inspections, I will discuss only the most common installations that may be
experienced by a fellow combination inspector.
Article 310 experienced a significant
reorganization in the 2011 NEC. The code-making panel made the changes in
order to comply with the requirements in the NEC Style Manual.
These changes included renumbering and relocating many requirements and tables,
so take a moment to compare the 2008 and 2011 codes.
In NEC 310.1, the scope states that this
article covers general requirements for conductors, type designations,
insulation, markings, mechanical strengths, ampacity ratings and uses. This is
followed by a disclaimer that this article does not apply to conductors that
are an integral part of equipment. This may be the case for motors, controllers
or other equipment assembled in a factory.
Photo 1. Example of a wire manufacturer multi-listing conductors
At this point, we need to jump over to Part III of
Article 310, which is 310.104 Conductor Constructions and Applications.
This is, basically, an introductory paragraph and Tables 310.104(A) through
(E). Of these, the most often used is Table 310.104(A) titled "Conductor
Applications and Insulations Rated 600 Volts.” Wire is generally referred to by
a letter designation, such as: TW, THW,
XHHW, MTW, and so on. Please open the code book and follow along on this table.
The columns will give you the maximum operating temperature, application for
dry, wet and damp locations, the material of the insulations, and wire size
ranges, along with other information.
For an example, let’s look at RHW and RHW-2. In the
first column, you will notice that RHW is a flame-retardant, moisture-resistant
thermoset insulation. It is rated for use at 75 degrees C and approved for dry
and wet locations. RHW-2 is rated for use at 90 degrees C, but otherwise has
the same properties as RHW. Next, let’s review XHHW-2, which is also a
flame-retardant, moisture-resistant thermoset rated for use at 90 degrees C in
wet or dry locations. So what is the difference? There are two differences in
the table. The first is the thickness:
RHW-2 has a much thicker insulation. The second is the use of a
covering: RHW-2 may have an outer
covering, while XHHW-2 does not. That is one reason you will never see an
"XHHN”; "N” stands for a nylon covering, but XHH (or XHHW or XHHW-2) does not
have an outer covering.
There is another condition that we need to cover
and that is dual-rated wire, which is commonly found in the field. One of
the most common is THHN/THWN-2; you will notice that these are both
thermoplastic insulations; however, one is for dry and damp locations and the
other is for dry and wet locations, both rated for 90 degrees C. Manufacturers
will dual mark conductors which meet both standards so that they can produce
one item for multiple applications. This saves them from having to run several
different products and constantly changing the process from one to the other.
The letters in the wire designations represent
insulation characteristics. A "T” generally means thermoplastic insulation,
while X stands for thermoset insulation. One "H” means that the conductor is
one level higher on the heat rating above the beginning point of 60 degrees, so
one H would signify 75 degrees. A double "H” ("HH”) moves you up to the
90-degree range. The "W” in the legend gives us the approval for wet locations,
and the "N” usually means a nylon outer coating. So let’s see if we can figure
out what XHHW means, using these general rules. First, the "X” stands for
thermoset; second, the "HH” means it is rated for use at 90 degrees C; and
last, the "W” means it is approved for wet locations. Notice, however, that the
Table indicates that XHHW can only be used at 75 degrees C in wet locations, so
you have to be careful about using only the letters printed on the conductor.
The lesson here is the letters may get you close, but you cannot assume they
tell the whole story; take the time and double-check them against Table
310.104(A). Additionally, UL has a Wire and Cable Marking Guide that explains
the letter designations and insulation types in depth.
Photo 2. Conductors installation found by an inspector. For those who have been following our articles, please do some review and see what code violations you can identify.
references above, we have mentioned temperature ratings; these temperatures are
the maximum temperature that a conductor insulation will reach under full load
at a stated ambient temperature. All the values stated above are in Celsius, so
to put it into something we are more familiar with, a 90 degree C conductor is
good for 194 degrees F. If a conductor is exposed to a temperature higher than
that for a prolonged period of time, the insulation cannot be depended on to
protect the conductor and will, in all likelihood, start to breakdown.
Jumping back to Part II of Article 310, we cover
Installation of conductors. First, we have Uses Permitted in 310.10, which
is divided into eight sections lettered (A)– (H). These include dry, dry and
damp, and then wet locations. As we have mentioned above, the properties of
certain insulations are made to withstand exposures to various conditions; for
descriptions of these locations, please refer back to the Article 100
definitions under "Locations.”
In 310.10(E), the code covers the application of shielding.
This is usually not in the scope of the work that is performed by the everyday
combination inspector. Shielding is applicable to voltages over 600 volts, and
we have mostly kept this series of articles to 600 volts and below.
The next two sections cover direct burial and
corrosive locations. This is simple, you must have conductors that are
identified and suitable for the conditions under which they are installed. If
there is an unusual condition, you may have to ask the installer, engineer or manufacturer
for information indicating that the conductor or insulation is suitable for the
Parallel is covered in 310.10(H). Often when working with higher ampacities, we
find it to be cumbersome and expensive to keep increasing the size of the wire
and conduit. The solution is often to use multiple runs that are connected to a
common location on each end. Notice in the 2011 edition of the code that much
of this section is highlighted gray, indicating new or revised text. The change
here was that the previous code stated that you were permitted to parallel
conductors 1/0 AWG and larger; however, it didn’t specifically prohibit you
from paralleling smaller conductors, which was the intent and the way it was
enforced in all my years of enforcement. However, that’s not what the actual
language said, and ambiguous language can cause enforcement issues;
therefore, in the 2011 code it was made clear that you are only allowed to
parallel conductors 1/0 AWG and larger.
There are some very critical and specific
requirements to be followed for parallel runs. These are covered in
310.10(H)(1) through (6). We will cover these in detail. Each conductor for the
same phase, polarity, neutral, grounded or grounding conductor must be of equal
length, consist of the same metal, be the same size in circular mil area, have
the same insulation type and be terminated in the same manner. These items are required
and should be on the top of every inspector’s mind when encountering parallel
I have seen or had calls on installations where these
conditions were not followed, and the issues that result are unequal loading on
the conductors and overheating causing damaged equipment and conductors. Keep
in mind that when we say terminated in the same manner, we mean exactly
the same lugs, number of bolts and size of the lugs, etc.
Photo 3. After reading 310.15, how would you derate the conductors in this wiring gutter? Hint, also see 366.22.
Continuing with parallel installations, if the
conductors are run in separate cables or raceways, the cables or raceways shall
have the same number of conductors and shall have the same electrical
characteristics. This means that you cannot have one run in PVC conduit and the
other in rigid galvanized conduit as these have very different electrical
properties. Parallel runs are also subject to any derating conditions found in
310.15(B)(3)(a), which we will cover shortly.
In 310.10(H)(5) and
(6), we cover the equipment grounding conductors and equipment bonding jumpers.
The equipment grounding conductors (where used) shall be sized according to
250.122, which is based on the overcurrent device which is feeding the
conductors. The equipment bonding jumper shall be sized according to 250.102,
which is based on 250.66 according to the size of the conductors used.
Before we jump into temperature limitations, we
need to start with the tables related to 310.15(B). There are six tables
here starting with 310.15(B)(16). I know some of you may wonder why we start
with the first table numbered 16; this is for ease of use, because this table
was previously known as 310.16. It was changed to comply with requirements in
the NEC Style Manual, which requires tables referenced within an
article to have the same number identification as the article. There never has
been a clause numbered 310.16, so for us long-time code users, the code-making
panel decided to keep the 16 present in the table designation. This also helps
to facilitate the thousands of references in other materials within the
industry that reference ampacities.
Please read the
differences between the headings of each of the tables found in 310.15(B); you
will notice that one table may apply to conductors in a raceway; another may
give values related to conductors run in free air. Some tables may refer to
different conductors rated for a higher temperature. The table that you will
use the majority of the time is 310.15(B)(16). So, you might as well tab that
page or dog-ear it so you can find it quickly. This table covers the common
conductors used in construction; you will notice that it is split down the
middle, with copper conductors on the left, and aluminum and copper-clad
aluminum on the right side. For those who have never heard of copper-clad
aluminum, it is aluminum conductor that has an outer coating of copper.
The last part of 310 we are going to cover and the
most laborious part is temperature limitations
of conductors. These factors take
into account the number of conductors within a raceway, the location of the
conductors, and what they are exposed to that may increase the ambient
temperature around them.
So let’s start in
310.15(B)(3)(a), where we cover the number of current-carrying conductors in a
raceway or cable. You will notice in the title of Table 310.15(B)(16) that it
is based on three current-carrying conductors, so if we exceed that number we
have to do an ampacity adjustment. The idea here is that when conductors carry
electricity, they heat up according to the load. Since our table has only taken
into account three conductors, we have to lower the values allowed when we use
additional current-carrying conductors. The table to reference is Table
310.15(B)(3)(a), where we find that if we use 5 current-carrying conductors, we
would have to apply an 80% correction factor to the values given in
310.15(B)(16). So, a 2 AWG aluminum XHHW-2 conductor would be good for 80 amps
instead of 100 amps if there were only 3 conductors. A note that has to be
covered here is found in the second paragraph of 310.15(B), which states the
adjustment or correction of a conductor is allowed to be applied to the rated
temperature value of that conductor. So if you have a conductor which falls in
the 90 degree column, then you can start with that ampacity value, as long as
the final calculated ampacity value does not exceed the temperature limitations
of the termination points. If your conductor starts in the 90-degree column and
you derate it to a value that exceeds the temperature rating of the equipment
(which is generally rated at 60 or 75 degrees C), you are not allowed to use
that conductor at a value above the termination ampacity. So for the example of
2 AWG XHHW-2, if you derated it from 100 amps to 80 amps, but we were
terminating it onto equipment that was only rated for 60 degrees C, we wouldn’t
be allowed to run it at an ampacity higher than 75 amps. This works throughout
the ampacity adjustment portion of the code; however, because you can start at
the actual conductor temperature rating, it frequently allows us to run smaller
conductors overall due to the improved insulation properties of the higher
Now that we have
the number of conductors in a raceway out of the way, we can jump back to the
Ambient Temperature Correction Factors found in 310.15(B)(2). You will notice
that at the top of each of the ampacity tables, in the heading it states that the ampacities are based on a certain ambient
temperature, either 30 degrees C or 40 degrees C. If the conductors are exposed
to temperatures other than the stated ambient temperatures that the tables are
based on, we must adjust the ampacities accordingly. The code has two
temperature adjustment tables, one based on 30 degrees C and the other based on
40 degrees C, and these are Tables 310.15(B)(2)(a) and (b). When you look at
these tables, you will notice that the column headings are conductor temperature
ratings. After you find the conductor temperature rating, you go down that
column to the row that applies to your ambient temperature exposure. This can
go both ways; if we look at the 30 degree C table and your installation is in
an environment that is between 11 and 15 degrees, the wire will be able to
handle 22% higher current than it would at 30 degrees C. Conversely, if you
have your installation in 100 degrees F (which is equal to 38 degrees C), then
you have to adjust the allowed ampacity by a factor of 82%.
items regarding these factors are covered in 310.15(B)(3)(3). One item states
that the adjustment factors do not apply to underground conductors entering or
leaving an outdoor trench if they have physical protection in the form of
various conduit types listed, as long as the length of the conduit does not
exceed 10 feet. There are other modifications in this section, be sure to read
through the entire text of 310.15(B)(3)(b).
consideration relates to having different portions of the conductor run though
different temperature environments. For example, if you have a raceway that is
run inside a facility that has a controlled temperature and then it penetrates
the roof to feed a piece of equipment, we have to take the higher of the two
ambient temperatures for derating, unless the higher temperature exposure is
not more than 10% of the total run or 10 feet, whichever is less. So if we have
an 80 foot run, only 8 feet can be exposed to the higher temperature, or we would
have to apply a temperature correction. If the run is 100 feet or longer, the
maximum exposure before temperature correction would be 10 feet. This is
covered in 310.15(A)(2) Exception.
There are several
other items regarding temperature correction of conductors within Article 310;
however, in the interest of time and recognition of the situations that are
most commonly found during combination inspections, I have just touched on the
most significant items. Please take the time to crack open your code book and
review some of these other applications that may apply in your specific
The last item for this article is 310.15(B)(7), which
is a special table related just to dwelling services that are 120/240-volt
single-phase. The table related to this article allows a specific wire size
based on the rating of the service or feeder. This is a very special allowance
which is based on the fact that in dwelling units we have very conservative
load calculations versus the actual demand at any time in a dwelling. As such,
we know that the actual loads on dwellings are much lower than the calculated
load, and this table takes that into account. For instance, a 3/0 AWG copper
conductor could be used for a 200-amp load based on the 75 degree C column of Table
310.15(B)(16), and in the dwelling table you will find it is allowed to be used
for a 225-amp service.
As I said earlier, this part of
the code is the most frequently used due to the fact that every installation
has conductors. As we install these conductors, we have to follow the various
code requirements from Article 310 that apply based on our unique installation
conditions. Thanks for taking the time to read this article, and I hope this
helps to improve your code knowledge and inspection ability.
Read more by Randy Hunter
Posted By Jesse Abercrombie,
Tuesday, November 19, 2013
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If you are starting out as an investor, you might be feeling overwhelmed. After all, it seems like there is just so much to know. How can you get enough of a handle on basic investment concepts so thatyou are comfortable in making well-informed choices?
Actually, you can get a firm grip on the investment process by becoming familiar with a few basic concepts, such as these:
Stocks versus Bonds. When you buy stocks, or stock-based investments, you are buying ownership shares in companies. Usually, it is a good idea to buy shares of quality companies and to hold these shares for the long term. This strategy may help you eventually overcome short-term price declines, which may affect all stocks. Keep in mind, though, that when buying stocks, there are no guarantees youwill not lose some or all of your investment.
By contrast, when you purchase bonds, youare not becoming an "owner”; rather, you are lending money to a company or a governmental unit. Barring default, you can expect to receive regular interest payments for as long as you own your bond, and when it matures, you can expect to get your principal back. However, bond prices do rise and fall, typically moving in the opposite direction of interest rates. So, if you wanted to sell a bond before it matures, and interest rates have recently risen, you may have to offer your bond at a price lower than its face value.
For the most part, stocks are purchased for their growth potential (although many stocks do offer income, in the form of dividends) while bonds are bought for the income stream provided by interest payments. Ideally, though, it is important to build a diversified portfolio containing stocks, bonds, certificates of deposit (CDs), government securities and other investments designed to meet your goals and risk tolerances. Diversification is a strategy designed to help reduce the effects of market volatility on your portfolio; keep in mind, however, that diversification, by itself,cannot guarantee a profit or protect against loss.
Risk versus Reward. All investments carry some type of risk. Stocks and bonds can decline in value while investments such as CDs can lose purchasing power over time. One essential thing to keep in mind is that, generally, the greater the potential reward, the higher the risk.
Setting goals. As an investor, you need to set goals for your investment portfolio, such as providing resources for retirement or helping pay for your children’s college educations.
Knowing your own investment personality. Everyone has different investment personalities. Some investors accept more risk in hopes of greater rewards than others who are not comfortable with any risk. It is essential that you know your investment personality when you begin investing, and throughout your years as an investor.
Investing is a long-term process. It generally takes decades of patience, perseverance and good decisions for investors to accumulate the substantial financial resourcesthey’ll need for their long-term goals.
By keeping these concepts in mind as your begin your journey through the investment world,you’ll be better prepared for the twists and turnsyou’ll encounter along the way as you pursue your financial goals.
Read more by Jesse Abercrombie
Posted By David Conover,
Wednesday, November 13, 2013
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Energy storage has been in use for centuries,
as evidenced by dams and the use of the stored water to drive mechanical
devices associated with grain milling. Energy storage provides the ability to
balance the energy capabilities and resultant outputs of variable energy
sources with the needed energy inputs of differing and variable loads. For
example, if the availability of the sun’s energy could be directly matched
continuously over time with the electrical lighting loads in a building, then
there would be no need to store the sun’s energy as converted into electrical
power through a photovoltaic (PV) system; the electrical energy would go
directly to the lighting system, and demand and PV capacity would be in total
agreement. The variability associated with building operations, climate, and
the lack of 24-hour sunlight necessitates some way to store the electrical
energy generated by the PV system for future use. In this case, the storage
technology is a battery to store the electrical energy.
Courtesy of Portland General Electric
Electrical storage today is not fundamentally
different—in concept—than it was 100 years or more ago; just the range and type
of technologies used, the size of the systems, their location and
ownership/operational situations (grid or customer side of the meter), their
interconnection with other systems, and their intended applications are
increasing in depth and breadth. Due to factors spurring market demand for
energy storage technology, North America is expected to see the most growth in
energy storage over the next five years. Grid-scale storage will increase
globally upwards of 10 gigawatts over that same period. This includes not just
grid or commercial size systems but residentially focused systems in the 5 to
25 kW range.1 The projected
US market for energy storage in 2015 is estimated at $10 billion annually.2
What might have involved the assessment of some
wiring, conduit and electrical connections, and a determination of the safe installation
of one or more lead-acid batteries just over 100 years ago is changing. This
necessitates the need for those responsible for ensuring the safety and
performance of electrical systems to understand what is coming. Principles that
are applied to any electrical system are no different; it is just that the
application may not look as familiar as more traditional electrical technology.
The purpose of this article is to provide an update
on energy storage technology, making electrical inspectors less likely to be
surprised when seeing new energy storage system technologies and better
positioned to foster the acceptance of new storage technology.
Energy storage has been used in a number of
ways for centuries; not necessarily in the manner in which we would think of it
within the context of today’s built environment. More contemporary applications
storing electricity have been around for about 200 years, beginning with the
invention of the modern battery by Volta in 1799. Building on that initial
work, lead-acid batteries were applied in the 19th century for a
number of applications, most notably to store generated power during the day.
Then, that storage for example could supply overnight lighting loads as was
done in New York City when they first
started to use electricity to light the city using dc current.With the first
applications of electric power in the US, including storage batteries, the
first National Electrical Code (NEC or NFPA 70) was published in
Other than for emergency electrical backup, and for
time-shift from coal to replace natural gas during non-peak periods in electrical
generation, and the increasing use of pumped hydro to generate power, there was
little change until about 30 years ago. By the mid-1980s there was increasing
interest by utilities to develop batteries and other storage technologies to
support the electrical grid. During this time, there was increased emphasis on
demand side management that fostered increased use of renewable energy and the
application of combined heat and power systems in and around buildings. These
and other factors have created a demand for energy storage systems; a demand
that is fostering significant growth in storage technology research,
development, availability, application and use, not only on the grid side of
the meter but on the customer side of the meter where both stationary and
vehicular systems are in play.
Courtesy of Green Energy Futures
Energy, environmental and economic challenges
here in the US and globally are spurring activity associated with new
energy-related technology. Electric power plays a critical role here in the US
and globally. It is something we cannot do without, but with increases in
energy demand, the need to improve power reliability, flexibility and to reduce
costs associated with electric power delivery there is an increasing need to be
smarter about what we do and how we do it. Electrical storage has a more
important and critical role to play; a role much larger than providing backup
power or helping utilities effectively use energy sources in generating
electric power as it has in the past. This is driving the investment in storage
technology development and deployment, even to the point of looking at how
vehicular systems can also serve stationary energy needs. Certainly, there is
an increasing need for utilities to upgrade their investments in generation,
transmission and distribution services. Customers also have an increased
emphasis on power quality, reliability, and the ability to time-shift and
manage demand charges. In addition, movement toward a Smart Grid that seeks
through automation the improvement of the grid to address the above challenges
is heavily dependent on the availability of energy storage technology and is
helping to drive technology development. Efforts to deploy renewable
technologies such as solar PV are also driving demand for energy storage. Of
note, the biggest challenges hindering adoption of this storage technology are
cost, deployability, and lack of standards.1
Figure 1. Energy Storage Technologies1
One could argue that standards (and codes)—or the
lack thereof—have a direct impact on cost and the ability to deploy the
technology. The absence of criteria upon which to evaluate technology
performance and safety leaves advocates and granters of technology approval
with little to go on other than evaluating the technology on the basis that it
is "no more hazardous nor less safe and it performs at least as well as other
technologies that are specifically covered by existing standards and codes.”
For instance the increased deployment of PV systems and energy storage are
driving the need for revisions to the NEC with respect to criteria for
dc systems; something new in buildings and to many of the NEC
code-making panels. As covered above, the technology is here now and is likely
to enjoy increased deployment in the future. Electrical inspectors can benefit
from having a basic familiarity with energy storage technology. More
importantly, they need to know that standards and codes and the infrastructure
that supports the use of those documents are being addressed now with the goal
of having the necessary criteria and programs in place and upon which system
approvals can be readily considered when the availability of systems begins to
fully address these increasing energy, environmental and economic challenges.
Energy storage technologies
There are a myriad of energy storage
technologies in terms of design, capacity and function. They include batteries,
pumped hydro, electrochemical capacitors, compressed air, flywheels and thermal
storage. Essentially anything that can store energy (electrical, thermal, kinetic)
for future use can be considered energy storage. Within battery storage there
are lithium-ion, fuel cell, lead-acid, nickel metal hydride, alkaline and
The Department of Energy (DOE) International Energy
Storage Database provides considerable information on the energy storage
projects operating or planned in the US, North America and globally
(ihttp://www.energystorageexchange.org). Further information on energy storage
technologies is available in the DOE/EPRI 2012 Energy Storage Handbook in
Collaboration with NRECA that was released June 2013.
Currently available storage technologies include
batteries and other non-battery technologies such as pumped hydro, thermal
storage, flywheels and compressed air, as shown in figure 1.
Battery story technologies, which will be of primary
interest to electrical inspectors, include the following:
(NaS), which have a discharge period of about six hours, can provide prompt and
precise response, and operate at 300 to 350°C. They use metallic sodium that is
combustible if exposed to water, hence they are constructed in airtight,
double-walled stainless-steel enclosures. Where cells are combined, they are
surrounded by sand to mitigate fire.
Sodium-nickel-chloride (NaNICl2) are
high-temperature devices like NaS with cells hermetically sealed and packaged
into 20 kWh+/- modules.
Vanadium redox batteries (redox) are a type of flow
battery in which at least one of the active materials associated with the
battery is in solution in the electrolyte at all times. The electrolytes are
stored in external tanks and pumped to the cells as needed. Each cell has an
open-circuit voltage on the order of 1.4 V with higher voltages achieved by
connecting cells in series to create cell stacks. Useful life is estimated at
about 10 years.
Iron-chromium (Fe-Cr) redox batteries are another
type of flow battery, but are in the R&D stage and just entering field
are also flow batteries in the 5 kW to 1000 kW range that are in the early
stages of field-testing and have a storage duration from two to six hours. Each
cell has two electrode surfaces and two flow streams; noting that the bromine
is extremely corrosive. During normal operation they are not unusually
environmentally hazardous, but the materials they contain can become
Zinc-air batteries are metal to air electrochemical
cells where oxygen in the surrounding environment serves as an electrode.
Lead-acid batteries, originally invented over 150
years ago, are widely used and comprised of carbon-based and advanced
technologies, the latter using enhancements such as granular silica electrolyte
Lithium-ion (Li-ion) are most common now in electric
vehicles and for portable power applications. Field demonstrations are underway
in the 5 to 10 kW/20 kWh for distributed system and 1 MW/15 minute fast
responding systems for frequency regulation. Some are able to provide backup
power for up to three hours during a grid outage.
Figure 2 provides a number of data associated with
energy storage systems used for frequency regulation. Data for other system
applications such as bulk storage and residential applications are also shown
in the cited reference.
Figure 2. Battery Storage System Type, Size and Cost Data.1
Beyond the battery chemistry and "what is happening
inside” individual cells, cell stacks and pre-packaged battery systems there
are a number of other components that include switching systems, power
conversion and conditioning systems, transformers, motors, controls and
communications systems, and related software. For some of these systems there
will also be fluid piping, tanks and associated pumps, motors and controls.
Within the boundary that defines the system, electrical safety and other health
and life safety issues will need to be addressed. In addition, across that
system boundary there will be electrical, and possibly also thermal, fluid and
gaseous inputs and outputs to consider; not just with respect to how the system
could impact its surroundings but how an event associated with the surrounding (such
as a fire) could impact the system. Some will focus specifically on electrical
safety and others will also require consideration of other health and life
The Electrical Inspector’s role in energy storage
The goal of
an electrical inspector is to ensure the safety of the built environment as
well as the public to the degree that they can be directly or indirectly
affected by electrical systems or equipment, products and components associated
with those systems. With respect to energy storage systems that involve
electrical energy as inputs and/or outputs there are a few conditions to
consider in framing a discussion on the role of the electrical inspector;
noting that as with other types of equipment and systems there may be as much
emphasis on protecting the storage technology from the surrounding environment
than the other way around.
System size – is the system unitary in nature,
composed of a matched set of components or simply designed, assembled and installed
from a number of different "parts”?
System complexity – is the system simply a
"box of battery cells” and some wiring and controls or are there also fluid
and/or gas storage, piping, and controls involved?
System installation and location – what is the
proximity of the system to buildings, facilities and the general public and is
it stationary or mobile?
System relation to the grid – is the system on
the customer or grid side of the meter and if on the customer side how is it
interconnected with the grid?
System ownership and operation – is the system
owned and/or operated by a utility (e.g., under PUC jurisdiction), a federal,
state or local governmental agency, a contracted third-party energy provider,
or a building owner/facility manager?
One way to get a
handle on this issue is to contrast the extremes and how the electrical
inspector would likely address them. Those extremes are a pre-packaged singular
unitary system (kW size) that is installed in, on, or adjacent to a building
that is accessible to the general public. Then, a much larger system (Mw size)
is assembled and installed on site, from a number of separate "parts”; both are
on the customer side of the meter and are owned and operated by the building
owner. To frame another set of extremes, consider those above, but on, the
utility side, and not necessarily located in, on, or adjacent to buildings
accessible to the general public. Simply stated, the former NOT latter in this
case could be residential in size, pre-packaged (unitary) and simply be
"delivered and hooked up.” The latter
could be grid-size and located adjacent to a utility transmission station or a
large utility-owned PV farm.
With those extremes, it is also important to
recognize any key differences from more traditional electrical equipment and
systems. One of those is that storage systems, or at least certain components
of the system, will always be energized and cannot be simply turned off. This
affects commissioning and operation of systems, but may also necessitate treating
the installation differently than more traditional "off/on/off” equipment.
Another difference is that the storage systems can contain exotic materials
that may be affected by fire, water/flooding, seismic events, and other
external factors. In this instance, the electrical inspector would be focused
more on the location and installation of the system to protect the system from
its environment as opposed to the opposite condition. As noted above, they can
also involve stored and/or moving fluids and/or gases as inputs and outputs
from the system.
Transformers of the new Salem Smart Power Center that houses a 5-megawatt battery and is operated by Portland General Electric, a research partner of Pacific Northwest National Laboratory. Courtesy of Portland General Electric
In the simplest of situations, the electrical
inspector would verify that the system (e.g., unitary pre-packaged) had been
"tested and listed” by an approved third-party agency thereby validating that
the system and its components satisfied a particular standard or number of
standards where conformance with those standards supports that the system
is "safe”. Then the inspector would
determine that the system was installed in accordance with the terms of its listing
and any adopted codes that are relevant (e.g., the NEC). Wiring methods,
circuits, disconnecting means, grounding, clearances, ventilation of interior
spaces, marking/signage, the existence of live parts, current
limiting/overcurrent protection, etc., would essentially be conducted no
differently than if the device was an electric furnace instead of an electrical
As the system increases in size and capacity, its
installation and location scenarios change, and its relationship to the grid
and the ownership and operation conditions can also vary. The role of the
electrical inspector may become more challenging; however, the fundamentals
will remain the same as with the simplest of situations. Building on the
information above for unitary-type systems, there would be virtually little
difference in the roles and responsibilities of the electrical inspector if the
system was composed of matched "tested and listed” components. The only
additional effort is to ensure that each component of the system is connected
in conformance with the terms and conditions of the listing and adopted codes
as to clearances, ventilation, signage, etc. When those components are not a
matched "package” but instead the system is essentially assembled on site from
various "parts” then all of the above
items (acceptability of the components, their proper connection and compliant
installation) must still be addressed. The challenge is that the criteria for
doing so are not likely to be provided by a single entity (e.g., a manufacturer
of the system). Instead, the criteria will come from each component
manufacturer and the guidance on the assembly of the components and their
individual and collective assembly will be guided by adopted codes such as the NEC
or from other standards that may be written specifically to address the
installation of such systems; as is the case for instance for NFPA 853 for
stationary fuel cells.
There are also the same exact scenarios above on the
customer side of the meter but with a utility actually owning a system that is
located in, on, or adjacent to a private or public sector building or facility.
In those instances, even though the utility is involved, the same
considerations above would be applicable, although the inspector would be more
likely to also be dealing with utility personnel in the review, inspection and
approval process. There is a similar issue with utilities, utility property,
and part of the utility systems and equipment that make up and support the
business of generating, transmitting, and/or distributing electric power to
customers. In those situations, the same general concerns would apply but the
criteria used as a basis for acceptance would be those adopted by the utility
and are likely to be based on the National Electrical Safety Code
One additional consideration is the system life after
initial inspection and approval. Typically, once a certificate of occupancy is
issued the electrical inspector’s role with a building or facility is completed
unless there is an addition, repair, renovation, etc., associated with the
building or its systems or system components. Where existing and previously
inspected and approved batteries are replaced, renewed, rehabilitated, etc., an
electrical permit and subsequent review of the construction documents and
inspection of the work may be necessary. For grid-side systems, this review
would likely be addressed by the system owner (the utility). For customer-side
systems, the notification of pending work on the system should occur through a
permit application by the building owner, facility manager or electrical
ES system performance
Beyond the specific health and life safety
aspects associated with an energy storage system is the performance of a system
with respect to its intended function (i.e., peak shaving, frequency
regulation, renewables smoothing). The availability of uniform, reliable,
consistent and comparable information on system performance fosters market
acceptance of such systems and eliminates the need for potential customers of
such systems to develop their own separate criteria. Some performance
information, such as system capacity and rating, is relevant to electrical
inspectors, even if minimum performance thresholds are not within the scope of
the electrical inspector’s function based on adopted codes and standards.
To address the lack of uniform, consistent and
singularly acceptable criteria for measuring and expressing energy storage
system performance, the US DOE’s Office of Electricity Delivery and Energy
Reliability (OE) Energy Storage Systems Program, through the support of PNNL
and Sandia National Laboratories (SNL), fostered an industry wide collaboration
to develop a protocol for measuring and expressing the performance
characteristics for energy storage systems. The protocol was published in late
2012 and currently provides criteria for all-electric systems intended for
either peak shaving or frequency regulation applications. For those
applications, the protocol addresses the definition of the system boundaries,
what measurements are to be taken, the duty cycle to be applied to the system,
and the methods for determining and reporting system performance from the
resultant operational data. Both applications are evaluated as to capacity, round
trip energy efficiency, response time and duty cycle round trip efficiency. The
frequency regulation application also is
evaluated for ramp rate and reference signal tracking.
Most recently a
user’s group applied the protocol to a number of system installations and based
on their experiences further refinements were suggested to the protocol. Those
suggestions are being communicated to both US and International standards
developers who are using the protocol as a basis for more traditional standards
on system performance. In addition, work is concluding on enhancements to the
protocol to cover applications of systems for microgrids and frequency
smoothing of renewable energy systems. The core format of the protocol and the
process for its development and enhancement serves as a foundation for future
standards development and deployment, which in turn assists the industry at
large. More importantly this model for criteria development and availability of
underlying supporting documentation fosters the more timely availability of
specific criteria in standards and codes that electrical inspectors can use in
assessing and approving new technology.
The market drivers discussed above will
continue to provide an opportunity for and encourage technology development and
deployment. This statement holds true no matter the time frame in which it is
considered. Just as a market driver for energy storage in the late 1800s might
have been "we need to store the electricity we generate during the day to light
the lights at night” and the business opportunity associated with artificial
lighting at that time, storage technology has evolved since then, is evolving
now, and will continue to evolve in the future.
inspectors some things will remain the same, others will change – more likely
they will be new. What will remain the same is the physics associated
with electricity. While what is "inside the box” may change and necessitate
different considerations, the connections to that box, the associated controls,
and what is flowing through the wires and conduit to/from the box will not
fundamentally change. Beyond that, as evidenced by some of the storage
technologies noted above, there may be an increased need to coordinate with
those involved in building, fire, plumbing and mechanical code enforcement to
address the integration of the system with the remainder of the built
environment in, on, or around buildings. Clearly if the system is of a
particular size and/or type those responsible for zoning may also need to
become involved with respect to setbacks and emergency vehicle access.
As the technology
evolves it will be incumbent for the storage industry to engage all
stakeholders, including those involved in electrical and related code
development, adoption and enforcement. Concurrently it is appropriate for those
same stakeholders to proactively become more engaged with the storage industry
at the individual level or through associations and organizations such as IAEI.
This article is an example of that outreach.
technical, there is also the non-technical or administrative environment. The
clear distinction between what is and is not covered by the utility is
changing. This will impact who is responsible for the adoption and enforcement
of codes, standards and other criteria to govern system installation,
commissioning and use. Training, licensing of electrical contractors, and a
number of other issues will also have to evolve to keep pace with and to
facilitate the acceptance of storage technology.
Electrical inspectors – now more than ever– play an
important role in addressing our energy, environmental and economic challenges
by fostering the acceptance of energy storage technology. The key overriding
factor is to ensure the safety of not only the public at large but of those who
are intimately involved with such systems in a thorough and timely manner. The
infrastructure that has been in place to ensure that safety and foster new
technology acceptance can and will, with your help and dedication, grow and
evolve to address new technology; in this case, electrical storage systems.
1DOE/EPRI 2013 Electricity Storage
Handbook in Collaboration with NRECA, SAND2013-5131, July 2013
2Power Systems of the Future: The Case for
Energy Storage, Distributed Generation, and Microgrids, IEEE Smart Grid,
November 2012 (www.smartgridresearch.org)
3Protocol for Measuring and Expressing the
Performance of Energy Storage Systems,
November 2012, PNNL-22010 (www.pnl.gov/main/publications/external/technical_reports/PNNL-22010.pdf)
About Pacific Northwest National Laboratory
Northwest National Laboratory, located in southeastern Washington State, is a
U.S. Department of Energy Office of Science laboratory that solves complex
problems in energy, national security, and the environment, and advances
scientific frontiers in the chemical, biological, materials, environmental, and
computational sciences. The Laboratory employs about 4,400 staff members, has
an annual budget of about $1 billion, and has been managed by Ohio-based
Battelle since 1965.
Posted By Thomas A. Domitrovich,
Wednesday, November 13, 2013
| Comments (3)
In the last edition of this column, we reviewed the incredible receptacle and the standards requirements around these products. Well, I left out one important piece of the puzzle: the tamper-resistant receptacle (TRR). These devices deserve to be put on a pedestal, so to speak as they work every day to protect our future — those little bundles of joy who at times become intrigued by those tiny slots in walls that seem to demand the insertion of paper clips or just about any other object that may seem to fit. Tamper-resistant receptacles are a direct response to statistics of children who tried to do just that and ended up in the hospital.
Just as with any new requirement in our industry, many people question new technology and resist adoption of these types of requirements. The fact is that many new code changes are supported by statistics and data at their core; the TRR requirements are no different. This is why the TRR requirements have fared so well in those jurisdictions adopting the National Electrical Code (NEC). The data behind the requirements for these devices include U. S. Consumer Product Safety Commission (CPSC) data over a 10-year period that found more than 24,000 children under 10 years of age were treated in emergency rooms for receptacle-related incidents, and more than 10% of those children suffered severe shock and burns. An average of seven children a day suffered from some type of injury from electrical receptacles. Eighty-nine percent (89%) of those injured were under six years of age. Fifty percent (50%) of those injured were toddlers. It was very interesting to learn that the vast majority of these incidents occur in the home where, more than likely, children are under adult supervision.
These devices may be relatively new to residential structures but, the fact is, they have been around for decades; mandated in hospital pediatric wards since NEC 1981 as part of Section 517-90(b) "Pediatric Locations.” The language in this section required, "Fifteen- or 20-ampere, 125-volt receptacles intended to supply areas designated by the governing body of the health care facility as pediatric wards and/or rooms shall be tamperproof. For the purposes of this section, a tamperproof receptacle is a receptacle which by its construction, or with the use of an attached accessory, limits improper access to its energized contacts.” Over time, this section has changed including the removal of the "tamperproof” terminology. These devices are resistant to tampering, not impervious to the act.
It was NEC 2008, as a part of Section 406.11, that introduced these devices as requirements for new and renovated dwelling units. As with every code change and it seems like every new safety provision, some resist local adoption of these types of new requirements. Even in light of opposition, the adoption of this provision has progressed quite well from state to state with approximately four states amending their requirement.
It’s All about the Shutters
The main goal of a TRR is to provide a level of protection to help prevent a child from inserting an object into one of the blade openings of the receptacle. When you look at the face of a TRR, you will notice that the two blade openings have what appears to be a barrier. The round hole, the one that received the grounding pin of the plug, does not have a shutter. Touching or inserting an object into the round hole of a properly wired device is not advised, but because it is the ground reference point should not result in harm to the inserter, more than likely a very curious child. In a NEMA 5-15, 15-A 125-V device the two slots that have barriers are, of course, the hot and neutral (grounded) parts. The object of the design is to ensure that the act of probing with an object, let’s say a bobby pin, safety pin or other similar object, in any single slot does not successfully let it penetrate to the energized components internal to the device.
Insertion is permitted when both slots receive a blade at the same time. In a typical mechanism, inserting a plug compresses a spring, simultaneously opening both shutters. While insertion of an object in any single shutter will not open the device such that the shutter slides out of the way. This sophisticated approach to the shutters ensures that curious George does not successfully hit "pay dirt” and end up in the emergency room. Because these devices have a very important goal and are a bit more complex than the standard receptacle, the UL standard for receptacles was modified to include new requirements. Additional tests for the TRR are included in UL 498, "Standard for Safety Attachment Plugs and Receptacles.”
A Standards Perspective
So let’s peek under the hood and look at the standard requirements behind the products that entered the receptacle world of heavily used and often abused electrical devices.
UL defines this device as "A receptacle which by its construction is intended to limit improper access to its energized contacts in accordance with the National Electrical Code, ANSI/NFPA-70.” In true form for UL 498, "Standard for Safety Attachment Plugs and Receptacles,” tamper-resistant receptacles are subjected to performance requirements that go above and beyond those performance requirements for standard receptacles. The following performance criteria are additional items to those discussed in the last edition of this column.
1. Probe Test: This test starts fresh with twelve untested devices. A probe of specific dimensions, similar to that of a paper clip, is applied to each of the receptacle’s slot openings, at a force of 8 ounces. The test attempts to bypass the tamper-resistance mechanism by manipulation in the slots in any orientation. An indicator is wired to the probe and the wiring terminal of the outlet slot being tested to announce if contact is made. In addition, these devices are subjected to another set of probes for a period of 5 seconds at a force of 10 lbs., looking for a way to bypass the tamper-resistance mechanism.
2. Impact Test: This test uses six of the twelve devices used in the previous test and subjects them to either a ball-pendulum impact or a vertical-ball impact test which strikes the receptacle face or tamper-resistance mechanism or other. The test is trying to determine the ability of the tamper-resistant mechanism to withstand an impact and continue to function. The receptacle cannot crack and the tamper-resistant functionality cannot be compromised. The sphere used is 2 inches in diameter and weighs in at 1.18 lbs. For the pendulum test, the sphere is suspended by a cord and swung like a pendulum. It is dropped 51 inches and the impact is of a 5.0 ft-lb force. In the vertical impact test, the sphere drops from a height of 51 inches and impacts the center of each receptacle.
3. Mechanical Endurance Test: This test uses six devices that previously were subjected to the above probe test. In this test, a machine continuously inserts and withdraws — 5,000 times — an attachment plug having secured solid brass blades. The machine controls the velocity of the withdrawal and insertion; the blades, contacts and tamper-resistant mechanisms must not be adjusted, lubricated, or conditioned in any way before or during this test. After this test, these devices are tested again to ensure attachment plugs can be mated; probes cannot compromise the tamper-resistance ability, and it can perform for the dielectric voltage withstand test.
4. Dielectric Voltage Withstand Test: A TRR must withstand without breakdown, for a period of one minute, the application of a 60 Hz voltage of 1000 V plus twice the rated voltage rating of the receptacle. The devices used again are those previously used in the above tests.
As can be seen here, these devices are given no relief from a standards perspective; they must perform when called to do so.
This is an internal view of how both shutters must be acted upon to permit the blades of the plug to be inserted.
A question that often graces code adoption hearings and other similar venues is the question of insertion force. Inevitably, you hear about concerns of someone having difficulties inserting a plug into the receptacle. The presence of shutters and the lack of familiarity will understandably generate these types of concerns. As shown above, these receptacles do not undergo any additional testing beyond the standard receptacle with regard to insertion forces. If you recall from our last article on the receptacle, insertion force is covered as part of section 117.8 of the standard. This section performs conditioning on the receptacle and requires that the standard blade, which the Standard calls a "gauge,” assembled without the grounding pin and with the line blades without holes, be inserted into each outlet of the receptacle. The insertion forces are measured and must meet specified criteria. As per this requirement, forces must not exceed 40 lbf required to seat a standard gauge against the receptacle face. Again, this is the same requirement for a standard receptacle.
Insertion of plugs in the case of TRRs is physically achieved in the same manner as that for standard receptacles. There is no getting around the fact that some additional frictional forces are present when inserting plugs into these receptacles; the shutters do provide some additional resistance during the processes of insertion. The additional forces are not significant. Problems may arise, though, due to application issues due to various situations contributable to the misuse or abuse of these products. One good example of arguably a less obvious abuse is drywall sanding. There have been reported cases where receptacles present during the process of sanding by drywall finishers have experienced plugging of their shutters. These devices are no different from many other electrical devices and care should be taken during construction. Another example of where insertion may be impacted includes those times when plug blades have been bent and so abused that they are barely recognizable as plug blades. A standard receptacle can be quite forgiving for the insertion of these abused objects. A TRR is much less forgiving than the standard receptacle. Hand tools such as drills and similar are infamous for this in venues where I have personally been involved. Irons, hair dryers, and we cannot leave out the vacuum sweeper, are also guilty offenders. I have had to take pliers to a plug or two to enable its insertion into a standard receptacle as well as the TRR. Another very abusive habit for plugs is the rapid yank to remove from an angle instead of walking up and removing it in the correct manner. Sometimes we are our own worst enemies. There are always opportunities to explain the correct way to remove plugs from receptacles and outlet strips and to demonstrate the proper use of these types of devices. There have also been reports of new plugs that are very sharp at the tip of the blades and catch on the shutter, digging into the shutter’s plastic, making it difficult to insert. Those burrs may be the result of a manufacturing process issue or for other post manufacture reasons, but are easily enough dealt with all the same.
Industry References and Resources
The industry has some very helpful resources for additional information on the tamper-resistant receptacle. The National Electrical Manufacturers Association (NEMA) has put together a web site resource to answer all of your questions and to give you enough information to ask additional ones. This resource can be found at www.childoutletsafety.org.
As always, keep safety at the top of your list and ensure you and those around you live to see another day.
Read more by Thomas A. Domitrovich