Posted By Muktha Tumkur and Victoria Alleyne,
Wednesday, January 15, 2014
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The popularity of solar photovoltaic rooftops has created a need
for guidance on their installations, given many building codes in Canada do not
address relevant photovoltaic safety and structural issues. A lack of guidance
in this area can expose installers and first responders, such as firefighters,
needing rooftop access to residential and non-residential buildings to
unnecessary risks. The new CSA Group SPE-900, Solar Photovoltaic
Rooftop-Installation Best Practices Guideline provides guidance and best
practices for the design and installation of photovoltaic rooftop systems.
SPE-900 addresses the following areas:
Designers are guided on evaluating how the integration of
photovoltaic modules on building affects the roof’s fire performance
characteristics. The National Building Code of Canada (NBCC) requires roof
coverings regulated under Division B, Part 3, to have a Class A, B or C
Classification to protect the roof covering material from ignition in the event
of a roof exposure fire originating from sources outside a building. Guidance
related to the requirements in ULC 1703, CSA C22.2 No 61730-1 and 61730-2, and
CAN/ULC-S107 is included. Pre-cautionary steps related to stand-off mounted
photovoltaic systems as they relate to the NBCC classification are also noted.
For direct or indirect lightning strikes,
SPE-900 provides precautions for surge arrestors and lightning protection in
buildings where there is a critical nature of the power distribution system.
Since the design and installation methods used in installing a photovoltaic
system can help reduce the level of risk associated with lightning-induced
surges, design considerations related to AC wiring, module wiring (string and
parallel string) and power cabling are included in the guideline. Precautionary
information related to the strength and bonding for the racking is also
SPE-900 recommends best practices for
providing safe working conditions for maintenance, inspection and service
personnel. A useful log sheet to record the inspection results for the
components of a photovoltaic system is included in Annex D. Risks related to
climbing and avalanches are also included.
Photo 1. Photovoltaic modules being installed on a building roof; previously there was a lack of comprehensive
guidance throughout the industry for safe installation.
At the time of publication, based on a scan of Canadian and
international building codes and guidelines, the structural clause in SPE-900
resulted because there were few, if any, specific requirements related to
roof-mounted photovoltaic modules and racks. Therefore, the largest section of the guideline is related to structural design. The
publication’s structural guidelines provide interpretation of existing code
provisions and best practices for the structural engineering aspects of
roof-mounted solar photovoltaic systems for new and existing construction.
When a solar photovoltaic system is installed
on a rooftop, it is important that it be designed to resist dead, live, and
other loads, and to recognize that it influences the loading conditions that
the building would otherwise have been designed for in the absence of the photovoltaic
system. SPE-900 helps ensure that a rooftop installation of a solar
photovoltaic system be designed to resist dead, live and other loads, and to
recognize that it influences the loading conditions that the building would
otherwise have been designed for in the absence of the photovoltaic system.
Because the NBCC doesn’t explicitly define loads on photovoltaic systems, nor
its influence on the building loading defined, detailed consideration for dead
loads is included.
Photovoltaic Modules and Racks
The guide includes consideration for the design and structural
resistance of photovoltaic modules and racks. Because it was noted that sliding
and overturning problems are unique to ballasted racks, a section with best
practices for the design of such systems is included. Designers are provided
with information for various types of building components including wood frame,
prefabricated wood trusses, open web steel joists, steel frames / decks,
concrete suspended slabs, hollow core precast slabs, etc.
SPE-900 also discusses waterproofing and the
durability of photovoltaic integration on commercial roofs before, during and
after installation to minimize any unintentional adverse effects due to the
waterproofing functionality of the roof assembly.
Because solar photovoltaic electrical issues
are addressed by the Canadian Electrical Code Part I, Section 50 and Section
64, SPE-900 does not duplicate these requirements, but rather points the user
to the relevant sections of the Code. Likewise, the guideline does not include
aspects covered in National Fire Protection Association (NFPA) 70, Article 690.
As always, local authorities having jurisdiction are the touch point for
electrical and structural permit requirements for photovoltaic rooftop
installations because specific requirements may vary by jurisdiction.
As a future development, CSA Group
has worked with stakeholders and is evaluating the need to develop the SPE-900
into a standard for photovoltaic installation for rooftop and ground mount. In
evaluating this opportunity, CSA Group would look into any existing documents
related to fire and building construction so that conflicting requirements are
Muktha Tumkur, P. Eng., Program Manager of Renewable Energy.
Alleyne is project manager, Renewable Energy, CSA Group.
information on this guideline contact Victoria Alleyne via email or through the CSA Communities – to purchase this document please
Posted By David Clements,
Wednesday, January 15, 2014
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"This is a new year. A new beginning. And things will change.” Does this quote from Taylor Swift pertain to IAEI? Absolutely!
Before I talk about what is new in 2014, let me reflect on our 2013 IAEI Section Meetings. From August 23 to October 9, 2013, I had the privilege of attending all six IAEI meetings. My fourth time attending all six meetings, which started back in 2007 when I was president and for the past three years as your CEO/Executive Director.
For those that have attended this year’s meetings or maybe one in the past you understand what I’m referring too. The value proposition in attending one of the IAEI Section Meetings is second to none.
Let me explain. The educational program at the U.S. Section meetings covered the major changes in the 2014 NEC. The Analysis of Changes presentation and code panel discussions were conducted by highly competent and respected individuals who are directly involved in the development of the NEC. Where else would one have the ability to ask questions, hear the background and rationale for the change, and have direct access to these experts in non-formal setting?
At the Canadian Section Meeting, the educational program consisted of several presentations. Ark Tsisserev, from Stantec Engineering, presented on Section 24 and Z-32 Standard; Randy Hunter, from Bussmann, presented on Fuse Selection; and Pablo Diaz, on GST Grounding. They too are experts in their respective fields and highly regarded and did an excellent job.
In addition, to the educational programs offered at each meeting there were trade shows in which vendors had an opportunity to market their products and services. This year we had a record number of vendors, and many of the vendors participated in all six meetings. Thank you to all the vendors for their continuing support.
Another important feature at the Section meetings is the networking that takes place during break time, lunches and dinners, and during the trade shows. Having the time to talk to your peers, industry leaders, and code experts about similar issues and field problems is a great way to share and learn.
The energy and enthusiasm at these meetings were contagious. I become more and more energized as the meetings went on. I witnessed new members being welcomed, existing members being engaged, and, what is equally impressive, those who are no longer active in the electrical industry after many years of service still coming to the meetings. For these individuals and the partners who attend, the meetings are all about friendship, and socializing, and supporting electrical safety and IAEI’s mission.
So back to the value proposition — I don’t think one could find a better educational offering for the cost of registration, which on average was $285.00. Where else would one go to find this value? Membership certainly has it benefits.
So as stated at the beginning, "This is a new year. A new beginning. And things will change.” I am very excited about 2014 and the direction IAEI is taking. We are starting the year on a positive note. Membership is on the increase; we will continue to offer premier education at the Section, Chapter and Division levels; the International Office Education Department will be expanding its on-site client base seminars and offerings and developing new ways to deliver training to the industry, such as through webinars; and we are expanding into interactive publications. As to "things will change,” we will be embarking on a realignment of the IAEI brand, a stronger emphasis on marketing and the use of social media, and making enhancements in our technology infrastructure that will assist us in providing the best service and value to our members.
Standing still and thinking about the past is not an option. A consultant that the Board recently hired to conduct an organizational assessment stated, "It’s all right to look back, just don’t stare.” Looking forward will allow us to shape the future of IAEI.
Read more by David Clements
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 126.96.36.199.(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 188.8.131.52. 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