Posted By Thomas A. Domitrovich,
Friday, March 01, 2013
Updated: Wednesday, February 13, 2013
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Recognizing shock hazards can be difficult to the untrained or inexperienced eye on job sites and especially areas / facilities that have experienced storm damage. An electrocution is the result of coming in contact with a lethal amount current. Shock protection comes in many forms with ground-fault circuit interrupters (GFCIs) being that last line of defense of protection; as long as you are lucky enough that this type of protection has been installed and installed correctly. There are many ways to stay safe, we simply need to train our eyes and implement the correct procedures and tools to facilitate it.
Based on data from the National Institute for Occupational Safety and Health (NIOSH) National Traumatic Occupational Fatalities (NTOF) surveillance system, electrocutions were the fifth leading cause of death from 1980 through 1995. The 7,326 deaths caused by electrocutions during this period accounted for 7.8% of all fatalities in the workplace and averaged 488 deaths per year. Electrocutions were fifth as compared to motor vehicle incidents (#1), machine related deaths (#2), homicides (#3) and, finally, falls (#4). Yes, it is hard to protect from something you can’t see, but there are lines of defense that you can use to ensure you do not come in contact with energized conductors and/or equipment.
Based on data from the National Center for Health Statistics (NCHS), the total number of electrocutions in the United States has decreased from 670 in 1990 to 400 in 2000. This is a reduction of 40%. During this same period, an estimated number of electrocutions related to consumer products decreased from 270 to 150, a whopping 44%. The work we do in codes and standards is driving these numbers in the right direction. Product standards are making the necessary changes to ensure products are more robust with this regard, installation codes like the NEC are including changes that help to provide the protection needed in new structures being built and work practices standards like NFPA 70E help to address safety in the workplace. On top of all of this activity, we are more educated on the topic of shock protection through articles such as this and IAEI training events like those held across the country every day.
Figure 1. Electrical tape or similar methods are not a fix for these types of severe neglect.
Lines of Defense
There are many ways to avoid coming in contact with energized conductors and equipment and there are various documents that help us understand how to do just that. The primary document that comes to my mind on this topic is the National Fire Protection Association’s (NFPA) number two best seller, NFPA 70E, "Standard for Electrical Safety in the Workplace.” In addition to this document, the National Electrical Code, NFPA 70, also helps. Let’s review some important lines of defense.
Grounding and Bonding: NEC 2011’s Article 250 takes a total of 31 pages to help ensure the grounding and bonding of your system is such that equipment type ground faults have the lowest amount of impedance possible, resulting in them being high enough to be overcurrents that are cleared by the overcurrent protective devices in the circuit. Ground faults can be overcurrents if they are high enough to exceed the ratings of the conductors and other equipment. In fact, NEC 2011 Article 100’s definition of overcurrent includes ground faults; it states that an overcurrent is "any current in excess of the rated current of equipment or the ampacity of a conductor. It may result from overload, short circuit, or ground fault.” By ensuring an effective ground path, overcurrent protective devices can do their job in clearing these dangerous faults that if left unattended due to high impedances, could result in fires and even electrocutions should someone touch these energized parts. Acting to de-energize problem circuits before a person comes in contact with them or the equipment they energize helps avoid an electrocution from occurring.
Distance: Putting distance between yourself or others and a hazardous location is one sure way to prevent electrocutions. Barriers and guards can help ensure only qualified individuals are in work areas. NFPA 70E has provisions for limited approach boundaries and advises that physical mechanical barriers should be installed no closer than the restricted approach boundaries defined within that document. It’s advisable to use non-conductive barriers, especially where they may come in contact with energized parts. Tools also help to put some distance between you and the work you are performing that may present opportunities for you to come in contact with energized equipment. Tools such as communicating management systems will provide the ability to open or close protective devices or switches from the safety of an office well away from the equipment. Hot sticks and similar type devices also facilitate the separation needed. Your equipment, though, must be well maintained and inspected before every use.
Insulated Tools: Insulated hand tools, matting and other personal protection equipment (PPE) can help prevent electrocution should you or your tool come in contact with energized equipment. Ensure your tools have not fallen in to disrepair, as insulation that is there to protect you could be jeopardized. You may have hand tools with insulated handles worn through, creating safety concerns. Figure 1 is a severe case of neglect. Electrical tape or similar methods are not a fix for these types of problems. There comes a time when if your tools don’t pass basic visual inspections, they should be replaced. Some tools require more than just a visual inspection; specific testing to identified standards may be required. NFPA 70E’s Table 130.7(C)(14), "Standards on Protective Equipment,” provides reference documents for various PPE items you will use on projects.
Rubber protective products require visual inspection before every use. Table 130.7(C)(14) has the following with respect to these types of products. Rubber Protective Products — Visual Inspection Standard Guide for Visual Inspection of Electrical Protective Rubber Products ASTM F 1236 - 96(2007)
Figure 2. This drawing Illustrates that the ground-fault sensor must have both conductors passing through the device. This sensor senses an imbalance in current and sends the difference of current between that which is going to the load and that which is coming back from the load to the relaying equipment.
For even more detail on rubber insulating equipment, NFPA 70E has Table 130.7(C)(7)(c), "Rubber Insulating Equipment, Maximum Test Intervals,” yet another good example of testing frequency and reference test standards. This table advises that blankets should be tested before first issue and every 12 months thereafter. Gloves should be tested before first issue and every 6 months thereafter. Gloves are tested to ASTM F 496. This table addresses blankets, covers, gloves, line hose and sleeves.
Personal Protective Equipment: Your personal protective equipment is important on every job. You must not only maintain your PPE, but you must also ensure you are using the correct equipment for the job at hand. NFPA 70E 130.7(C)(15), "Selection of Personal Protective Equipment When Required for Various Tasks,” is the perfect reference for this line of defense. This section includes a wealth of information providing guidance on which PPE should be utilized for various types of projects. This section includes those tables illustrated above as well as hazard / risk category guidance to help convey which PPE is required when working on various types of equipment.
Working De-Energized / Lockout-Tagout: Yet one more way to ensure your team avoids electrocution is to work on de-energized equipment. We should always strive to work de-energized. Proper lock-out tag-out procedures should be followed, and effective testing techniques to ensure equipment is de-energized are important as well.
GFCI Protection: The acronym GFCI is used quite often and if I were to hazard a guess, I would say that very often it is used incorrectly. It is not only important to use terminology correctly but to also understand the limitations of the various ground-fault devices out there to facilitate in their proper application. GFCI protection is your last line of defense that is hopefully provided in your situation. The next few sections will take a high level look at a few different types of ground-fault devices.
Safety Plan: Last but not least is your safety plan. This is that document that pulls together all of your safety procedures and policies providing your plan to electrical safety. This document is your springboard for safety training and reporting. It is the glue to all that is safety for your organization.
Figure 3. This image demonstrates all of the conductors passing through the sensor, as it is the job of the sensor to ensure all current is accounted for. Only 2-pole devices are adequate for these types of applications.
UL 943 vs. UL 1053 Ground-Fault Protection Devices
We’re talking people protection versus equipment protection when we set these two UL standards side-by-side. A device tested to UL 943, "Ground-Fault Circuit Interrupters,” is one that is intended for the protection of personnel. The Scope of UL 943 reads as follows: "This Standard applies to Class A, single- and three-phase, ground-fault circuit-interrupters intended for protection of personnel, for use only in grounded neutral systems in accordance with the National Electrical Code (NEC), ANSI/NFPA 70, the Canadian Electrical Code, C22.1 (CEC), and Electrical Installations (Use), NOM-001-SEDE. These devices are intended for use on alternating current (AC) circuits of 120 V, 208Y/120 V, 120/240 V, 127 V, or 220Y/127 V, 60 Hz circuits.”
A UL 1053, "Ground-Fault Sensing and Relaying Equipment,” device on the other hand is one that is designed to protect from equipment damage due to ground fault. The scope of this standard reads as follows: "These requirements cover ground-fault current sensing devices, relaying equipment, or combinations of ground-fault current sensing devices and relaying equipment or equivalent protection equipment for use in ordinary locations that will operate to cause a disconnecting device to open all ungrounded conductors at predetermined values of ground-fault current, in accordance with the National Electrical Code, ANSI/NFPA 70.” These types of devices help to prevent burn downs and other types of electrical fires.
A ground-fault device is going to be present to serve one of two basic needs: provide people protection or provide equipment protection. We’ll discuss the applications of both of these types of devices after covering some of the basics of ground-fault protection to help us understand their goals and their proper application. Suffice it to say that a device listed to UL 943 is designed for personnel protection and a device listed to UL 1053 is designed for equipment level ground-fault protection. Let’s take a quick refresher on how a GFCI device works before addressing the differences between these two basic types of devices.
Ground-Fault Device Operation Basics
A ground-fault device operates off of the basic principle of differential current; that current which goes out to the load through the hot conductor has to come back from the load over the neutral conductor. (Reference figure 2). The conductors involved are the expected paths for current. This applies to 2-wire, 3-wire or even more conductors in the case of three-phase installations. A three-phase device may appear to get a little more complicated due to phase angles and more hardware that needs to be installed, but you are still working off the basic fundamental principal of what goes out must come back over the expected paths, the conductors for the circuit.
A ground-fault device will employ two key components that work together to determine if ground-fault current is flowing. The system is comprised of sensing equipment and relaying equipment. The sensing equipment will come in the form of a current transformer that can be placed at various locations within the circuit. Sensing equipment and relaying equipment do not have to all be in one self-contained device. Industrial power systems will employ separate sensing equipment in the form of current transformers around bus bars or large conductors that must be wired back to the equipment. In the case of smaller ground-fault type devices like those you will find in residential applications, both sensing equipment and relaying equipment are located in the same small enclosure. Just to keep things simple, we’ll address what you would find in a residential ground-fault device as both of these key components are typically located within one small compact device.
Your basic ground-fault breaker or receptacle-type devices include a current transformer that surrounds the hot and neutral conductors of the circuit and a small circuit board that receives the signal from this sensor and makes the decision of whether or not to open the circuit. The conductors that pass through the sensor window must include all hot and neutral conductors serving the load. This is why, for shared neutral applications, you cannot apply a handle tie to two single-pole breakers and share the neutral. Both breakers need their own neutral return path. A two-pole GFCI device ensures the integrity of current flow through the internal current transformer for proper operation. (Reference figures 2 and 3 for examples of this).
Ground- fault currents are seeking the path of least resistance back to the source. NEC 2011’s Article 250 takes the time in a total of 31 pages to help you ensure the grounding and bonding of your system is the best it can be. For equipment ground faults, you want a low impedance path to the source. Article 250 helps get you there. Every wire connector and connection point in the grounding system is important to achieve your goals. If you have a good low impedance path to ground, your equipment type ground faults will become overcurrents that are acted upon by your standard overcurrent protective devices up stream.
Personnel Protection – UL 943
Now that we have a basic understanding of how ground-fault devices work, let’s explore what makes a ground-fault device a GFCI, one that is intended to protect personnel. To get electrocuted, three things are important: (1) the amount of current, (2) the path it takes through the body and (3) the amount of time it flows. A GFCI device does not know the path that current takes through your body and can have no control over that, but it can detect the amount of current and identify when to open the circuit. UL 943 defines these two key parameters for these types of devices. A GFCI device is designed to not trip for currents less than 4 mA and to always trip for currents above 6 mA. The amount of time it takes is determined by a couple of equations. For low-resistance faults, the equation is as follows:
For high-resistance faults, the equation is as follows:
So as an example, for a high-impedance fault which would result in a small current flowing, say 6mA as an example, the GFCI device as per the above equation will take 5.59 seconds to trip.
In reality, all GFCI devices trip much faster than that required by UL 943 and a 6mA fault would normally take no more than 0.1 seconds, with some margin for error, to be cleared by an off-the-shelf GFCI device.
To understand what this means to a person, the following table is used by many documents to describe the effect of current.
A GFCI device is designed to open the circuit to avoid the problems identified in table 1.
Table 1. The effect of current on humans
Equipment Protection – UL 1053
A device designed to this standard for equipment level protection is not meant to protect a person from electrocution. The UL standard for this type of device does not specify the current level at which it will pick up; it merely defines, amongst many other requirements, the amount of time it can take to clear. A UL 1053 device establishes the time criteria for clearing a ground fault at the pick-up level defined by the manufacturer of the device.
This performance criterion is not based on when the heart goes into defibrillation or when it may stop. This is an important thing to remember as it would be a mistake to apply a UL 1053 device, thinking you are going to achieve personnel protection.
Table 2. A UL 1053 device establishes the following as the time criteria for clearing a ground fault at the pick-up level defined by the manufacturer of the device.
There are many ways to prevent electrocution. Leverage your various lines of defense to avoid coming in contact with energized conductors and/or equipment; and as your last line of defense, ensure you have employed the correct GFCI device for personnel protection. GFCI devices are not required on every circuit at every voltage and for every application. Do everything you can to keep your distance, use insulated equipment, take care of your tools, and think and observe before proceeding in and around hazardous areas.
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
Posted By Joseph Wages, Jr.,
Friday, March 01, 2013
Updated: Wednesday, February 13, 2013
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The National Electric Code, in Article 650, contains the electrical requirements for pipe organs. Pipe organs have been in existence since early Greece in the third century B.C. They were viewed at one time as the greatest of human achievement. But why on earth is there an article in the NEC dealing with these music producing instruments?
A Little History
Pipe organs have been around a long time. In the early years, these devices used water pressure for the production of wind to produce their all too familiar sounds. Unlike a piano, the pipe organ continues to produce its desired sound as long as the pedal is depressed. Many of us have fond memories of hearing these at churches and cathedrals from around the world. Their unforgettable sounds have been played in musicals and movies such as The Phantom of the Opera. Who can forget those eerie (or to some, wondrous) sounds!
Many dignitaries have been laid to rest in the presence of the sounds of this instrument. Presidents and other world leaders have been resting in state or officiated over with the accompanying sounds from the pipe organ. Thousands of weddings have been officiated over and joyful lifetimes begun in buildings that employ these magnificent instruments. The pipe organ has played a large part in many religious ceremonies throughout the ages and continues to do so to this day.
The oldest playable organ was built in 1430. It is known as Organ Sion Switzerland Notre Dame de Valere. As one might expect, there are many locations in Europe that have famous pipe organs that have been around for hundreds of years. The largest pipe organs in the United States are found in Atlantic City, New Jersey, and Philadelphia, Pennsylvania. One of the most well-known locations is the Washington National Cathedral. There are many official events held yearly at this historic location. A recent earthquake on the East Coast had many concerned about whether there had been any extensive damage to the structure or contents of the building. There had been some damage to the building but the organ was unharmed. One construction worker remarked, "God watches over this building.”
Electricity and Electronics
The advent of electricity led inventors to replace mechanical and wind action with electro-pneumatic and electric action. By using low-voltage direct current (dc) electricity, keyboards could use electronic magnets with valves and electro-mechanical actions to play the pipe work. Electricity also allowed other musical sounds to be played with the organ pipes, mimicking the sounds of other instruments.
The pipe organ also has a long history in the National Electric Code. I have researched our library at the IAEI back to the 1930 edition; and, as expected, there exists an article covering the pipe organ. It might be in earlier versions, as well, but I did not have them for my use at this time. Although the article has seen a few changes over the years, the pipe organ is still installed or maintained using the valuable information found within the NEC requirements.
Article 650 is a relatively short article compared to others in the NEC. One would not think that an article that is not well-known would still hold any relevance in the electrical industry. Believe it or not, there were changes within this article between the 2008 and the 2011 code cycle! This article falls under the purview of code-making panel 12 of the National Fire Protection Association. It is a pertinent article that has applications to a specific item that many in this industry may never have an opportunity to work on or inspect. But the application it serves for the pipe organ is relevant and important to the safety of the equipment, the public, and its user. Here is a brief overview of Article 650, Pipe Organs.
650.4 Source of energy is a transformer-type rectifier, not to exceed 30 volts dc.
650.5 Grounding requires the rectifier to be bonded to the equipment grounding conductor according to 250, Parts V, VI, VII, and VIII.
650.6 Conductors have restrictions of size, insulation, cable, and covering.
650.7 Cables shall be securely fastened in place and are permitted to be attached directly to the organ structure without insulating support, but not in contact with other conductors.
650.8 Overcurrent protection must be provided for 26 AWG and 28 AWG conductors at not more than 6 amperes; other conductor sizes are to be protected according to their ampacity.
One of the 2011 changes occurred in 650.3 concerning other articles in the NEC that apply to this article. Two additions were made to this section to include (A) Electronic Organ Equipment and (B) Optical Fiber Cable. Electronic organ equipment shall also conform to Article 640, Audio Signal Processing, Amplification, and Reproduction Equipment. Optical fiber cable shall conform to Article 770, Optical Fiber Cables and Raceways.
Another change occurred within 650.7 as it applies to the installation of conductors. The change deals with abandoned cables that do not terminate at the equipment. The change states that the cables shall be identified with a tag.
Photo 3. The introduction of electricity led inventors to replace the mechanical and wind action in pipe organs with electric action. Then, of course, that installation was covered in the NEC — in 1930 [the earliest version in the IAEI library]. Shown here are representative copies of the Code from the 1930s, 1950s, 1960s, 1990s, and the current 2011 Code.
But keep in mind that there are other requirements found in the NEC that apply to pipe organs. An example is found in Article 250.112(B) which speaks to a requirement for an equipment grounding conductor. This requirement applies to the generator or motor frame of a pipe organ, unless effectively insulated from ground and the motor driving it.
Pipe organs have had an impact on society for approximately 2300 years or more. With proper maintenance and installation practices, they will continue to fascinate and invigorate another generation of people. The articles that some believe are insignificant within the NEC often play a bigger role than some might expect. Take time to know the sometimes overlooked articles in your code book. They might just bring about a new appreciation for items like the pipe organ.
Read more by Joseph Wages, Jr.
Posted By Jesse Abercrombie,
Friday, March 01, 2013
Updated: Wednesday, February 13, 2013
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As an investor, how can you avoid making mistakes? It’s not always easy, because investing can be full of potential pitfalls. But if you know what the most common mistakes are at different stages of an investor’s life, you may have a better chance of avoiding these costly errors.
Let’s take a look at some investment mistakes you’ll want to avoid when you’re young, when you’re in mid-career, when you’re nearing retirement and when you’ve just retired.
When you’re young …
Mistake: Investing too conservatively (or not at all) — If you’re just entering the working world, you may not have a lot of money with which to invest. But don’t wait until your income grows; putting away even a small amount each month can prove quite helpful. Additionally, don’t make the mistake of investing primarily in short-term vehicles that may preserve your principal but offer little in the way of growth potential. Instead, position your portfolio for growth. Of course, stock prices will always fluctuate, but you potentially have decades to overcome these short-term declines. Since this money is for retirement, your focus should be on the long term — and it’s impossible to reach long-term goals with short-term, highly conservative investments.
When you’re in mid-career …
Mistake: Putting insufficient funds into your retirement accounts — At this stage of your life, your earning power may well have increased substantially. As a result, you should have more money available to invest for the future; specifically, you may now be able to "max out” on your IRA and still boost your contributions to your employer-sponsored retirement plan, such as your 401(k), 403(b) or 457(b). These retirement accounts offer tax advantages that you may not receive in ordinary savings and investment accounts. Try to put more money into these retirement accounts every time your salary goes up.
When you’re nearing retirement …
Mistake: Not having balance in your investment portfolio — When they’re within just a few years of retirement, some people may go to extremes, either investing too aggressively to try to make up for lost time or too conservatively in an attempt to avoid potential declines. Both these strategies could be risky. So as you near retirement, seek to balance your portfolio. This could mean shifting some of your investment dollars into fixed-income vehicles to provide for your current income needs while still owning stocks that provide the growth potential to help keep up with inflation in your retirement years.
When you’ve just retired …
Mistake: Failing to determine an appropriate withdrawal rate — Upon reaching retirement, you will need to carefully manage the money you’ve accumulated in your IRA, 401(k) and all other investment accounts. Obviously, your chief concern is outliving your money, so you’ll need to determine how much you can withdraw each year. To arrive at this figure, take into account your current age, your projected longevity, the amount of money you’ve saved and the estimated rate of return you’re getting from your investments. This type of calculation is complex, so you may want to consult with a financial professional.
By avoiding these errors, you can help ensure that, at each stage of your life, you’re doing what you can to keep making progress toward your financial goals.
Read more by Jesse Abercrombie
Posted By Barry O’Connell,
Friday, March 01, 2013
Updated: Wednesday, February 13, 2013
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In September 2012, both UL and ULC withdrew certification for Electrical Circuit Protective Systems (FHIT and FHITC) that employed fire resistive cables. This included UL Classified Fire Resistive Cable (FHJR), UL Listed cable with "-CI” suffix (Circuit Integrity), and ULC Listed Fire Resistant Cable (FHJRC). Certification was retained for systems that used protective materials like intumescent wraps, tapes, composite mats, etc.
Fire resistive cables are used for emergency circuits in many applications, including high-rise buildings and places of assembly. Emergency circuits include feeders for fire pumps, elevators, smoke control equipment, fire alarm systems and other similar circuits. These circuits are required by the National Electrical Code and the Canadian National Building Code to have a 2-hour fire rating. This added level of survivability is intended to allow sufficient time for building occupants to exit a building during an emergency and to provide uninterrupted power for fire fighting equipment and emergency communication systems.
There are two types of fire resistive power cable systems: polymer insulated cables that require conduit protection and armored cables that do not. Armored cable types include both mineral-insulated and metal-clad cable. The events that led to the certification withdrawal were based on systems employing polymer insulated cables, not armored cable.
In 2011, UL was informed of an issue with using polymer insulated fire-resistive cables in conduit systems coated with zinc. UL confirmed that a problem existed and issued a notice stating that fire-resistive cables should be used only with components free of zinc. UL expanded their research and conducted extensive additional testing that showed an unacceptable level of variability with all non-armored polymer insulated cables.
These findings led to the conservative decision to withdraw all certifications, including armored cable systems, even though there was no indication that similar issues existed with either metal-clad or mineral-insulated cables. Shortly thereafter, however, UL offered an interim test program to manufacturers of fire-resistive cable for possible re-certification of existing products.
After UL/ULC withdrew all fire resistive cable certifications, a joint meeting of the UL Standard Technical Panel on Fire Resistive Cables and the ULC Standards Committee on Fire Tests was arranged. The meeting took place on October 24, 2012, in Ottawa, Canada, where the committee reviewed available information and agreed to form task groups to evaluate and update the fire resistance test standards for cable systems. This process will include additional testing and review, and a revised standard is likely to take at least two years to complete.
Because mineral-insulated cable construction is completely different from the cable-in-conduit technology under investigation, UL/ULC worked with Pentair Thermal Management to reinstate Pyrotenax mineral-insulated cable as a 2-hour fire-rated cable system. The process included reviewing MI cable designs in detail, detailed technical explanations of the critical design factors related to mineral-insulated cable’s fire resistance, and extensive fire tests, in accordance with the interim test program performed at the UL facility in November and December of 2012.
On December 21, 2012, UL and ULC re-established certification of fire-resistive cables used in electrical circuit integrity systems. The first system to be included is Pyrotenax Mineral Insulated Cable, and it has been assigned a new identification: System No. 1850. Information can be found at www.ul.com in the Online Certifications Directory.
Read more by Barry O'Connell
Posted By Ark Tsisserev,
Friday, March 01, 2013
Updated: Wednesday, February 13, 2013
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This subject, similar to many other issues that relate to the application and installation of electrically connected life safety system, is far from being fully understood by the designers, installers and regulators.
And certain provisions of the legally mandated documents do not help the Code users.
Let’s elaborate: provisions for installations of exit signs are governed by Rule 46-400 of the Canadian Electrical Code (CEC).
This Rule states the following requirements:
"46-400 Exit signs
(1) Where exit signs are connected to an electrical circuit, that circuit shall be used for no other purpose.
(2) Notwithstanding Subrule (1), exit signs shall be permitted to be connected to a circuit supplying emergency lighting in the area where these exit signs are installed.
(3) Exit signs in Subrules (1) and (2) shall be illuminated by an emergency power supply where emergency lighting is required by the National Building Code of Canada.”
Appendix B Note on this Rule offers the following clarification:
This Rule applies only to exit signs connected to an electrical circuit. Other requirements for exit signs, including those not connected to an electrical circuit, may be found in Section 3.4.5 of the National Building Code of Canada.
The circuit supplying emergency lighting could be ac or dc. The National Building Code of Canada requires that exit signs be illuminated continuously while the building is occupied. Caution should be taken to ensure that a circuit supplying both emergency lighting and exit signs is not controlled by a switch, time clock, or other means.”
So far, requirements of the CEC appear to be straightforward, and the users of the electrical installation code clearly understand that in accordance with the scope of Section 46, these requirements are only applicable when such exit signs are "required by the National Building Code of Canada” (by the NBCC).
Photo 1. Old type exit sign—with the word "exit”
Photo 2. New type exit sign—with the green running man
As the NBCC is the "driving force” in respect to the application of exit signs, let’s take a look at the relevant provision of the NBCC.
Sentence 188.8.131.52.(1) of the NBCC states the following requirements for location of exit signs:
"184.108.40.206.(1) Every exit door shall have an exit sign placed over or adjacent to it if the exit serves
a) a building more than 2 storeys in building height,
b) a building having an occupant load of more than 150, or
c) a room or floor area that has a fire escape as part of a required means of egress.”
Sentences 220.127.116.11.(6) and (7) provide additional requirements for location of exit signs as follows:
"6) Where no exit is visible from a public corridor, from a corridor used by the public in a Group A or B major occupancy, or from principal routes serving an open floor area having an occupant load of more than 150, an exit sign conforming to Clauses (2)(b) and (c) with an arrow or pointer indicating the direction of egress shall be provided.
7) Except for egress doorways described in Sentence 18.104.22.168.(4), an exit sign conforming to Sentences (2) to (5) shall be placed over or adjacent to every egress doorway from rooms with an occupant load of more than 60 in Group A, Division 1 occupancies, dance halls, licensed beverage establishments, and other similar occupanciesthat, when occupied, have lighting levels below that which would provide easy identification of the egress doorway.”
So far – so good, as these NBCC provisions advise the code users of all possible locations where exit signs would be required.
Now, let’s take a look at what NBCC tells the Code users regarding performance of the required exit signs.
Sentence (2) of Article 22.214.171.124. mandates the following performance requirements for exit signs:
"(2) Every exit sign shall
(a) be visible on approach to the exit,
(b) except as permitted in Sentence (3), consist of a green pictogram and a white or lightly tinted graphical symbol meeting the colour specifications referred to in ISO 3864-1, "Graphical symbols – Safety colours and safety signs – Part 1: Design principles for safety signs in workplaces and public areas,” and
(c) conform to the dimensions indicated in ISO 7010, "Graphical symbols –Safety colours and safety signs – Safety signs used in workplaces and public areas,” for the following symbols (see Appendix A):
i) E001 emergency exit left,
ii) E002 emergency exit right,
iii) E005 90-degree directional arrow, and
iv) E006 45-degree directional arrow.”
Sentence (3) of Article 126.96.36.199. now mandates that internally illuminated exit signs must be illuminated continuously (and that such continuous illumination is required not only when a building is occupied, but at all times). This Sentence appears to allow two options for the internally illuminated exit signs: to be illuminated by being connected to an electrical circuit or by being able to provide "self-illuminating” capabilities, as follows:
"(3) Internally illuminated exit signs shall be continuously illuminated and
(a) where illumination of the sign is powered by an electrical circuit, be constructed in conformance with CSA C22.2 No. 141, "Emergency Lighting Equipment,” or
(b) where illumination of the sign is not powered by an electrical circuit, be constructed in conformance with CAN/ULC-S572, "Photoluminescent and Self-Luminous Signs and Path Marking Systems.”
It is also interesting to note that Sentence 188.8.131.52.(4) now recognizes externally illuminated exit signs that are illuminated not by being connected to an electrical circuit but by displaying self-illuminating properties as follows:
"(4) Externally illuminated exit signs shall be continuously illuminated and be constructed in conformance with CAN/ULC-S572, "Photoluminescent and Self-Luminous Signs and Path Marking Systems.”
Finally, the NBCC appears to confuse the users by the following statement in Sentence 184.108.40.206.(5):
"(5) The circuitry serving lighting for externally and internally illuminated exit signs shall
(a) serve no equipment other than emergency equipment, and
(b) be connected to an emergency power supply as described in Article 220.127.116.11.”
This apparent confusion is manifested by the fact that Sentence (4) does not appear to mandate illumination of externally illuminated exit signs by external lighting being connected to an electrical circuit (it appears to rely on self-illuminating properties of such externally illuminated exit sign); however, Sentence (5) references the "circuitry serving lighting for externally and internally illuminated exit signs.” To add to this confusion, Sentence (5) mandates that this circuitry must serve "no equipment other than emergency equipment.” Does it mean that this exit sign circuitry must serve such emergency equipment as a fire pump or firefighters’ elevator? This NBCC statement appears to be inconsistent with provisions of Rule 46-400 of the CEC quoted above as follows:
"46-400 Exit signs
(1) Where exit signs are connected to an electrical circuit, that circuit shall be used for no other purpose.
(2) Notwithstanding Subrule (1), exit signs shall be permitted to be connected to a circuit supplying Emergency lighting in the area where these exit signs are installed.”
So, let’s summarize the information presented above:
Exit signs are part of electrically connected systems mandated by the NBCC.
Article 18.104.22.168. of the 2010 edition of the NBCC has been clarified by removing wording "while building is occupied” from the requirements for the internally and externally illuminated exit signs to be continuously illuminated. Such clarification removed ambiguity on this essential safety requirement and allowed the users of the NBCC to appreciate significance of continuous illumination of exit signs in accomplishing fundamental safety objective in fire protection. NBCC introduced new signage on exit signs, by replacing the word "EXIT” by the green pictogram of a running man, as such pictogram meets provisions of the ISO standard.
However, Article 22.214.171.124. of the NBCC has also been revised – to recognize "Photoluminescent and Self-Luminous Signs” that are designed and constructed in conformance with the ULC standard S572 as the exit signs that meet the performance requirements of Sentence 126.96.36.199.(2); Sentence 188.8.131.52.(1) and Sentence 184.108.40.206.(1)(b) of the NBCC.
These NBCC Articles mandate the following performance requirements:
"220.127.116.11. Minimum Lighting Requirements
(1) An exit, a public corridor, or a corridor providing access to exit for the public or serving patients’ sleeping rooms or classrooms shall be equipped to provide illumination to an average level not less than 50 lx at floor or tread level and at angles and intersections at changes of level where there are stairs or ramps.
(2) The minimum value of the illumination required by Sentence (1) shall be not less than 10 lx.
18.104.22.168. Emergency Lighting
(1) Emergency lighting shall be provided to an average level of illumination not less than 10 lx at floor or tread level”
"22.214.171.124. Emergency Power for Lighting
(1) An emergency power supply shall be
(a) provided to maintain the emergency lighting required by this Subsection from a power source such as batteries or generators that will continue to supply power in the event that the regular power supply to the building is interrupted, and
(b) so designed and installed that upon failure of the regular power it will assume the electrical load automatically for a period of
(i) 2 h for a building within the scope of Subsection 3.2.6.,
(ii) 1 h for a buildingof Group B major occupancy classification that is not within the scope of Subsection 3.2.6., and
(iii) 30 min for a buildingof any other occupancy.”
Thus, such recognition of self-illuminated exit signs is articulated in Sentences 126.96.36.199.(3)(b) and (4)(b) of the NBCC, and as the result of this recognition the NBCC no longer mandates that the self-illuminated exist signs conforming to ULC S572 have to be illuminated from lighting connected to the electrical circuit.
When the internally illuminated exit signsconstructed to the CSA safety standard C22.2 No.141 are connected to an electrical circuit in accordance with Sentence 188.8.131.52.(3)(a) and in conformance with Rule 46-400 of the CE Code, the above referenced NBCC illumination performance requirements will be met. It means that under a normal power supply condition electrically connected exit signs will be continuously illuminated, and in the event of a normal power failure, the emergency power supply source will be provided to these electrically connected signs in accordance with the requirement of Sentence 184.108.40.206.(1)(a) of the NBCC. Such emergency power supply source will be able to provide continuous illumination of these electrically connected exit signs for a period mandated by the NBCC in accordance with the type of a building.
In addition, electrical connection of the internally illuminated exist signs will allow to conform with all applicable provisions of Sentence 220.127.116.11.(2)(b) of the NBCC (i.e. to comply with the ISO 3864-1 for a green pictogram and a graphical symbol), as each electrically connected internally illuminated exit sign complies with the CSA standard C860, "Performance of internally lighted exit signs.”
However, when "Photoluminescent and Self-Luminous Signs” (that are designed and constructed in conformance with the ULC standard S572), are installed in a building under provisions of Sentence 18.104.22.168.(3)(b), ability of each such "internally illuminated” exit sign to comply with provisions of the ISO 3864-1 for a green pictogram and a graphical symbol, and with provisions of the NBCC for a minimum of 10 lx of illumination under a power failure condition for a period up to 2 hours, is highly questionable, as the ULC S572 has no reference to the above stated NBCC performance requirements.
In addition, there is no requirement in the ULC S572 to mark these "Photoluminescent and Self-Luminous Signs” with the ULC certification monogram indicating that these self-illuminated exit signs conform to this ULC standard.
Thus, the users of the NBCC (designers, installers and regulators) would not have objective, consistent, transparent and measurable criteria for understanding whether such signs, in fact, meet the safety objectives of the NBCC for the illumination level and for the time period required for illumination at the NBCC prescribed level under power failure condition.
As was indicated above, Sentence 22.214.171.124.(4) of the NBCC creates confusion to the Code users, as this Sentence recognizes the signs constructed to the ULC S572 as also being "externally illuminated.”
This NBCC Sentence does not mandate an electric power supply source – to externally illuminate such signs in order to allow these signs to rely on their self-illuminating properties after the source of external illumination disappears.
It should be noted that the scope of the ULC S572 considers these signs to be furnished with "photoluminescent and self-luminous” properties (i.e., signs that are being illuminated by means of the internal self-illuminating attributes, but only after a source of ambient lighting to which these signs are exposed under normal conditions, disappears).
In fact, the following definition is provided in the ULC S572 "SELF-LUMINOUS — Illuminated by a self-contained energy source other than a battery, such as radioactive tritium gas. Operation is independent of external power supplies or other external forms of energy.”
Sentence 126.96.36.199.(4) simply outlines the requirements for circuitry serving lighting for externally and internally illuminated exit signs, but there is no requirement in Article 188.8.131.52. for the externally illuminated exit signs – to be illuminated by the lighting in the area where such signs are installed. And it was already noted that the wording of paragraph 184.108.40.206.(5)(a) is questionable, as it mandates "circuitry serving lighting for externally and internally illuminated exit signs serve no equipment other than emergency equipment.”
In light of the fact that the emergency equipment is not defined by the NBCC but is described in Article 220.127.116.11., the Code users might be under impression that the circuitry serving lighting for externally and internally illuminated exit signs could also serve such emergency equipment as fire pumps, fire fighters’ elevators, smoke control and smoke venting fans.
The writer of this article has advised the NRC staff that confusion related to this wording must be expediently removed from the Code, as this wording conflicts with 32-206 and Rule 46-400 of the CEC and with requirements of NFPA 20.
Electrically connected exit signs must be supplied only from a dedicated circuit or from a circuit that supplies emergency power to the lighting in the area where such exit signs are installed. Failure to recognize this fact in the NBCC will compromise the fire safety objective of the Code.
The writer of this article has recommended to the NRC staff the following:
1. Until ULC S572 is revised so, as to recognize performance requirements of the NBCC for illumination levels and the time period to provide such illumination levels by self-illuminating properties of the sign, to demonstrate compliance with the referenced NBCC performance requirements in specific tests reflected in the standard and to mandate marking by applying a certification monogram stating that each such sign is designed, constructed, tested and certified to the ULC S572 – to remove any references to self-illuminated exist signs and to the ULC S572 from the NBCC ASAP. Failure to do so will compromise fire safety.
2. To revise Sentences (3); (4) and (5) of Article 18.104.22.168. to read as follows:
"(3) Internally illuminated exit signs shall:
(a) be continuously illuminated;
(b) be connected to an electrical circuit; and
(c) conform to the CSA standard C22.2 No. 141.
(4) Externally illuminated exit signs shall be continuously illuminated by electrical circuits supplying lighting in the area where these exit signs are installed.
(5) Electrical circuits illuminating of exit signs described in Sentence (3) or (4) shall be:
(a)used for no other purpose; and
(b)connected to an emergency power supply as described in Article 22.214.171.124.”
Read more by Ark Tsisserev
Meanwhile, designers and installers of exit signs (if non-electrically connected exit signs are chosen for installation) should contact the relevant AHJ’s – to discuss all potential concerns.
Posted By Donald E. Bowen, Jr.,
Friday, March 01, 2013
Updated: Wednesday, February 13, 2013
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As the popularity of electric vehicles (EVs) continues to expand, the demand for charging station availability is also increasing at a rapid rate. EV infrastructure has quickly and quietly sprouted in many urban areas throughout the U.S. and along many interstate highways.
The advanced investment of this pathway infrastructure will continue to play a vital role in the adoption of EVs into our transportation system. However, continued integration of electric vehicles by consumers is dependent on the availability and ease of use of charging facilities.
Although the location and status of each unit may be identified through websites as well as applications on mobile devices, significant inconsistencies remain in the physical appearance, location, and access to this equipment. Electrical codes dictate the standards for materials, installation procedures, and connection to the electrical grid, but the user interface including physical access, signage, use limitations, area demarcations and cost are largely unregulated or standardized and are subject to the discretion of the facility owner. However, a few states have already devised guidelines to combat this problem. A wide range of regulations and policies in the states of California, Washington, Hawaii, Minnesota, Virginia, and Oregon stipulate everything from vehicle charging rates to the exact placement of EV charging systems, parking space dimensions, and signage.
Photo 1. Convenience is important.
For over a year I have been utilizing a wide variety of charging station facilities and have experienced a number of impediments which hinder the convenience of recharging my Chevy Volt. Many hotels, restaurants, supermarkets, and parking facilities have installed EV equipment, an amenity which is rapidly becoming a business imperative in the corporate world. Nonetheless, charging stations have not yet reached widespread prevalence in the most convenient locations. Areas where people are engaged in commerce for a period of hours, such as malls, golf courses, theaters, or transportation facilities, represent significant new opportunities for EV charger installation.
Photo 2. Signage is extremely important.
The vast majority of the charging units that I’ve used were identified through a mobile device prior to departing for unfamiliar destinations. Mobile applications such as PlugShare provide the locations of both private charge stations (which require advanced permission) and publicly available options. Vender specific mobile apps alert you to the location and availability of charging stations equipped solely by their company. Mobile apps usually provide the specific address of the host facility, conditions for use, user comments, level of charge capacity (120v or 240v), directions, and photographs to aid with navigation to the charging facility.
Photo 3. Accessibility is important.
Based on my use and observations of dozens of charging stations, I have compiled a list of Best Practices for facility owners and real estate managers to consider.
Signage is extremely important to locate and then operate the charging equipment. It should be large and well lit at night to avoid the need to search for EV charging stations, especially when entering a parking lot or garage. The vast majority of facilities that offer this amenity have limited instructional signage to direct vehicle operators to designated spaces.
Optimum content for signage:
•reservation of parking spot for electric vehicles only
•name and phone number of
organization responsible for operation and upkeep
•level of amperage
•user fee or rates
•consequences of violation of either time limit or type of vehicle:
"Violators will be towed at owners expense” towing company and telephone number days and hours of operation
An effective method of identifying a charging facility and its designated equipment is the demarcation of individual spaces using easily identifiable EV symbols with bright green paint either on the entire parking space or within one of several plug-in EV logos. Similar to the blue demarcations of handicap parking spaces, green designation of EV parking spaces assists with identification by EV operators and serves as a deterrent or vibrant reminder to conventional vehicle operators. The Seaport Hotel in Boston provides a fantastic example of a clean, well lit, properly designated charging facility.
Convenience will also play a significant roleas the purchase of EVs becomes more widely accepted. Unobstructed access to EV charging stations may seem logical, but I have found that a number of parking facilities have limited or prohibited access. Some restrict access by means of "residents only” or "Do Not Enter” signage, as seen at the Handover Parking Garage in Portsmouth, NH. I had a particularly difficult time tracking down one charging station noted on a mobile app when, after an extensive investigation effort, I was informed that the charging station was located in an underground parking garage referred to as Harbour Front Centre in Toronto, Canada. No trace of evidence on the ground would lead one to conclude that this charging facility even existed. A construction fence prohibited access and only through the kind-hearted assistance of facility staff did it become known that the garage was not even scheduled to open for another two weeks!
Photo 3. Lenox Hotel is the first privately owned, privately funded, company in the city of Boston to install a visible-to-the-public, electric vehicle curb-side charging station. Hotel and restaurant guests can receive complimentary valet parking along with free charging for their electric vehicle.
Accessibility measures may allow disabled persons a greater chance to operate an electric vehicle in a safer and more convenient environment. The first of every 25 EV charging spots, or any available and convenient space should be reserved exclusively for the use of disabled persons. This requires a parking space at a diagonal or perpendicular to the curb with ample space around the charging equipment as well as a barrier-free route of travel. Close proximity to the entrance of the building will allow equal opportunities to all electric vehicle drivers. Accessibility should also include sidewalk clearance for pedestrian passage if in a public area.
Charging station maintenance and protection should be put in place. Charging equipment may either have a retractable cord or a clear place to hang the cord at an appropriate height above the ground. Curbs, wheel stops, or steel bollards prove useful in protecting EV charging stations, especially those placed near an angled or perpendicular parking spot.
EV charging spots must clearly mark their policies and procedures in regards to payment or fees. If requiring a card reader, this device should be clear of obstruction, visible, and at easy level for reach. Free EV charging spots may promote energy efficiency or entice new customers or clients to the business providing the service. These free spots should be well promoted and clear for the driver to understand.
Public education is highly recommended to inform occupants, tenants and visitors of the availability and location of charging stations. This information should be available through websites for individual companies and facility owners. The public is far more likely to consider EVs if awareness of EV infrastructure and equipment is increased. In my opinion, the public charging stations available at City Hall in Boston have increased public awareness more than any other charging stations in New England due to their high profile location and near-constant use.
Use enforcement of EV parking spaces is necessaryto prevent conventional gas powered vehicle operators from occupying EV charging stations. Enforcement may pose challenges, given that the spaces are often in preferred areas, and are desirable due to proximity to elevators and stairwells, building access and pedestrian walkways.
As electric vehicle popularity soars, charging station availability through policing of time limitations will be critical to continued expansion. In addition to education of policies through proper signage, communication of charge completion is one method of insuring that idle equipment does not go to waste. The On-Star app for my Chevy Volt emails me upon complete charge or any premature disruption.
Illumination of parking space(s) is extremely helpful for the payment and use of charging stations. Despite vehicle safety considerations such as the illumination of the J1772 EV plug connection, dimly lit surroundings can make it difficult to identify charging equipment and designated spaces.
Read more by Donald E. Bowen, Jr.
As our transportation system evolves, these recommendations will maximize the potential use and benefit of EV charging stations. The adoption of such amenities serves as a strategic differentiator between forward thinking businesses and those who choose to fall behind in a competitive environment. Minimizing the time and effort necessary to utilize charging stations will improve integration of EVs into our transportation system, reducing both our reliance on foreign oil and our carbon emissions. Widespread and well-executed EV infrastructure will provide the groundwork for a stronger economy and healthier environment for our country now and for future generations.
Posted By Leslie Stoch,
Friday, March 01, 2013
Updated: Wednesday, February 13, 2013
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High ampacity services and feeders are often installed with conductors in parallel to reduce pulling tensions and for easier handling. I’m sure you are already aware that a long list of conditions comes with permission to parallel conductors. This article reviews the requirements of Rule 12-108 Conductors in Parallel along with some significant changes for such installations now provided in the 2012 Canadian Electrical Code.
Rule 12-108 specifies that, except for neutrals, control and instrumentation circuits, parallel conductors must not be smaller than 1/0 AWG copper or aluminum. No doubt this requirement is designed to limit use of parallel conductors to such circumstances where this wiring method is truly needed. We already know, the rule contains numerous precautions to ensure conductors in parallel are loaded as equally as possible, to prevent unbalanced loading, overheating and subsequent failures.
To ensure that conductors are loaded evenly, Rule 12-108requires that parallel conductors must have the same characteristics including identical sizes, types of insulation, methods of termination, wiring materials, lengths, orientation and without any in-line splices. Appendix B shows us the required conductor configurations. These special arrangements are designed to minimize differences in inductive reactance and sharing of load currents. The wire and cable manufacturer should be consulted if it becomes necessary to employ conductor arrangements different from those given in Appendix B.
Furthermore, Rule 12-904 requires that when parallel conductors are in cables or raceways, each cable or raceway must contain an equal number of conductors from each phase and the neutral. Each cable or raceway must also be of the same material and physical characteristics to ensure that conductor impedance differences are minimized. There are some very good reasons for this requirement. Should we for example, attempt to install parallel conductors in different conduit types (say PVC and steel), we would find unequal loading in the paralleled conductors for the reasons discussed above.
But now new challenges await us with changes to this rule. As you are by now aware, some of our earlier expectations are now being tested as the 2012 Canadian Electrical Code has made two important modifications to the above requirements:
Sub-rule (2) specifies that a single splice in each parallel conductor is permitted to meet the requirements of Rule 4-006 Temperature Limitation. You will recall that this rule requires that: "where equipment is marked with a maximum termination temperature, the maximum allowable ampacity of the conductor shall be based on the corresponding temperature column from Tables 1, 2, 3 and 4.” You will also recall that this rule applies to both ends of the conductor. If for example we are using 90° C rated wiring to connect to circuit-breakers marked with a maximum 75° C temperature rating, we would normally base our conductor ampacities on the 75° C columns of Tables 1 to 4. However, this newly minted change also allows us to splice on a larger wire size to meet the maximum wiring connection temperatures specified by Rule 4-006, thereby permitting use of the 90° C temperature rating. Although permissible, it’s still not a great idea, as each splice is a potentially weak link.
Sub-rule (3) specifies that: "in parallel sets, conductors of one phase, polarity or grounded circuit conductor shall not be required to have the same characteristics as those of another phase, polarity or grounded circuit conductor.” This opens the door for parallel conductors of one phase to be of a different wire size, material (copper or aluminum), length, insulation type and termination method as long as the parallel conductors of each phase have the same characteristics. I suspect that this change was designed to make things easier for repairs rather than for the initial installations.
Read more by Leslie Stoch
As with past articles, you should always consult with the electrical inspection authority in each province or territory for a more precise interpretation of any of the above.
Posted By Underwriters Laboratories,
Friday, March 01, 2013
Updated: Wednesday, February 13, 2013
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Does UL certify paint spray booths? Does UL provide a field evaluation service for paint spray booths?
UL certifies (Lists) paint spray booths under one of two categories, depending on whether fire protection systems are provided as part of the paint spray booth. The two categories are Paint Spray Booths without Fire Protection Systems for Use in Hazardous Locations (QEFA) and Paint Spray Booths with Fire Protection Systems for Use in Hazardous Locations (QEFY), both are located on page 317 in the 2012 UL White Book or online at www.ul.com/database (enter either QEFA or QEFY in the category code search field).
These categories cover paint spray booths for liquid and powder coating finishing processes as defined in Article 516 of NFPA 70, National Electrical Code (NEC) and in NFPA 33, Spray Application Using Flammable or Combustible Materials. Some booths may utilize electric heating, gas, gas-oil or an oil-fired heating system for drying. The type of heating employed is indicated in the individual certifications.
These paint spray booths are intended for field assembly indoors in accordance with instructions furnished by the manufacturer and the information marked on the equipment. They are intended to be installed and used in accordance with applicable requirements in NFPA 33 and Article 516 of the NEC. Paint spray booths located within a commercial garage are to be installed as defined in Article 511 of the NEC.
UL can only perform a field evaluation on a UL certified paint spray that has been modified after installation. Even these evaluations can be very challenging, depending on the nature of the modifications that were made.
Performing field evaluations on a paint spray booth that will be installed in a Classified hazardous location is very difficult because subassemblies or components have not undergone full certification testing prior to a field evaluation. There are many aspects of the installation such as ventilation, filters, dead air space validation, and potential destructive testing that would be required for assemblies to properly determine compliance with the applicable standard. Therefore, UL does not provide a field evaluation service for paint spray booths that have not been previously UL certified as a paint spray booths.
For information on initiating a Field Evaluation, please go to www.ul.com/field or contact UL Customer Service at 877-ULHELPS (877-854-3577) and select prompt number 2.
I have seen Listed (certified) roof top HVAC units that incorporate a receptacle for maintenance personnel to use while servicing the unit that are not ground-fault circuit interrupter (GFCI) protected. Are these receptacles required to be GFCI-protected in the UL Standard? Are they required to be covered by a wet location "while in use cover,” e.g., a "bubble cover”?
Roof top HVAC units are certified (Listed) under the product category Heating and Cooling Equipment (LZFE) located on page 239 in the 2012 UL White Book and online at www.ul.com/database and entering LZFE in the category code search field. These products are evaluated for compliance with UL 1995, the Standard for Safety of Heating and Cooling Equipment. Effective October 2014, UL 1995 will require a ground-fault circuit interrupter (GFCI) on all 125 or 250V, single phase, 15 or 20A receptacles intended for general use installed on heating and cooling equipment for outdoor use.
The receptacles will also be required to be of the weather-resistant type, and receptacles installed in wet locations shall be subjected to the rain test or have an enclosure that is weatherproof, whether or not the attachment plug is inserted (bubble cover).
In addition, receptacles connected to the line side of a unit disconnect will be required to have a separate disconnect.
Read more by UL
UL Question Corner
Posted By Steve Foran,
Friday, March 01, 2013
Updated: Wednesday, February 13, 2013
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The first time I came eye to eye with a 600-volt system was during the commissioning of a new amusement park. To me, the utility engineer, it was a low voltage system but not so to the customer and indeed 600 volts is a high voltage.
It was unusual for our utility to get involved in the commissioning of commercial businesses but the amusement park had some very large motors, in particular the flume ride motor. Although I can’t remember its horsepower, a full voltage start would almost look like a dead short circuit to the power system. Even with the starter controls on the motor, the amusement park ended up having restrictions on the number of times they could start the motor to eliminate the impact of voltage flicker on nearby customers.
Who is not familiar with the convenience of modern electricity — flick the switch and "on” goes the power? Yet there are relatively few people who understand the complex interconnectedness of a power system that enables us to turn on the switch, whether to a bathroom light or a flume ride. It’s true, isn’t it?
As an electrical inspection professional, you are part of this system.
Inspectors operate within an equally complex interconnected sub-system of people and processes that extend beyond the inspector’s workplace. This network includes colleagues from around the country or the globe, local and federal regulations, utilities, municipalities, businesses, electricians, and property owners in the communities you serve.
And the ultimate purpose of the electrical inspector is two-fold: first, to ensure electrical systems are safe; second, to facilitate the connection of end-use devices and systems that serve humanity.
Melodramatic? Maybe. True? Absolutely!
The impact of this perspective is significant. It elevates the work of electrical inspection to a calling. You may already see your work as a calling because of your responsibility to protect the safety and security of people and property. But I see your calling as something much larger.
Homes and schools are heated or cooled, factories are powered, food is prepared, hospitals are lit, technology is enabled and so much more all because of the safe reliable delivery of electrical energy.
Your calling as an electrical inspector is central to the well-being of humanity. Although it is seldom top of mind, but everything you do as an inspector on a daily basis, either directly or indirectly makes a difference in our world — all in support of this calling. Everything.
Seeing electrical inspection work as a calling is challenging. The complexity of the electrical system makes it hard to see the difference our actions make. And as is frequently the case, self-limiting beliefs about the nature of our work diminish our awareness to the point where the impacts of our actions are invisible to us. For those who do not overcome these challenges, the meaning of electrical inspection work is easily reduced to a mundane series of pass-fail transactions.
Like the flume motor that has the potential to trip upstream protection on the power system or to annoy nearby customers if started too frequently, your actions, in some way impact everyone with whom you are connected. This is true whether you see the impact or not. But unlike the flume motor, you can know you make an impact even without seeing the impact.
Read more by Steve Foran
It is absolutely critical to have a healthy, realistic pride both in one’s work and in the impact of one’s work. And it is up to electrical inspection professionals like you to spread the word about the Calling of being an Electrical Inspector.
Posted By Dan Neeser,
Friday, March 01, 2013
Updated: Wednesday, February 13, 2013
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Some of the most commonly used, but often misunderstood and misapplied devices in industrial control panels are manual motor controllers and self-protected combination motor controllers. The advantage of these devices is the reduced cost and size when compared to traditional motor controllers and combination motor starters.
The confusion with these devices results from the fact that the same device can be dual-listed as both a manual motor controller and a self-protected combination motor controller. On one side of the device, the listing and ratings are shown when applied as a manual motor controller. On the other side of the device, the listing and ratings are shown when applied as a self-protected combination motor controller. However, if applied as a self-protected combination motor controller, typically the ratings are reduced and additional accessories and marking requirements are needed. Hence, the question that results: is the device being applied as a manual motor controller or a self-protected combination motor controller? The answer is often unclear, which can complicate proper device application and equipment marking requirements for industrial control panel builders.
This article covers important safety criteria based on Code and Standard requirements for the proper application of manual motor controllers and self-protected combination motor controllers. As a field application engineer, the author finds these devices often misunderstood and misapplied. The objective of this article is to provide guidance to the reader to use the device’s instructions and markings to ensure proper application and marking when used in industrial control panels.
Figure 1: Traditional NEMA (left) and IEC (right) Motor Starters. Combination motor starters would incorporate a circuit breaker or fused switch ahead of the motor starter to provide motor branch circuit short-circuit and ground fault protection.
Manual Motor Controllers
Manual motor controllers, sometimes called manual motor protectors (MMP), are permitted to provide motor overload protection as required per NEC 430.32. MMPs may be also be used as a motor controller (ON-OFF Function) to meet NEC Article 430 Part VII. If marked "Suitable as Motor Disconnect” MMPs are permitted to serve as an "at the motor” disconnect per NEC 430.109, provided they are located between the final motor branch-circuit short-circuit and ground-fault protective device per 430.52 and the motor.
However, MMPs are not listed nor permitted to provide motor branch-circuit short-circuit and ground fault protection per NEC430.52. This is because their creepage and clearance distances are typically not sufficient as required by branch-circuit overcurrent devices such as UL 489 circuit breakers. Similarly, these devices do not have the creepage and clearance distances to be used as a motor branch-circuit disconnect. Thus, per NEC430.109 and UL 508A 30.3.3 , a motor branch-circuit short-circuit and ground-fault protective overcurrent device and branch-circuit disconnect are required on the line side of the MMP.
Figure 2: Examples of manual motor controllers (MMPs)
Figure 3: Possible applications of MMPs
Some MMPs have been tested and listed for group motor applications so that several of them may be able to be protected by a single motor branch-circuit short-circuit and ground-fault protective device, such as an upstream fuse or circuit breaker sized not to exceed the maximum ampere rating allowed per the device listing. In group motor applications, other limitations such as horsepower ratings and tap rule restrictions (per NEC 430.53 or UL 508A 31.4 for Industrial Control Panels) must also be investigated. Devices listed for use in group motor installations will be marked for such use to indicate that the device has undergone the appropriate testing to deem it suitable for such use. If investigated for tap conductor protection in group motor installations, they can additionally be marked "Suitable for Tap Conductor Protection in Group Installations.” The advantage of this marking is that the 1/10th rule for tap conductor protection per NEC430.53 and UL 508A 31.4 then applies versus the 1/3rd rule. This means the tap conductor to each manual motor protector must be sized suitable for the motor load but can be as small as 1/10th of the motor branch circuit short-circuit and ground-fault protective deviceversus 1/3rd of the branch-circuit conductors.
Figure 4: Example of MMP label
MMPs as listed to UL 508 will contain a marking near the agency symbol. This marking should read "Listed Manual Motor Controller” or an abbreviation such as "Man. Mtr. Cntlr.” MMPs listed for use within group motor applications, as the downstream, protected overload/controller device, will be marked for such use along with the required maximum ampere rating for the upstream fuses. MMPs, additionally listed for use as an "at the motor” disconnect, will be marked "Suitable as Motor Disconnect.” MMPs, additionally listed for use as protection of tap conductors in group installations, will be marked "Suitable for Tap Conductor Protection in Group Installations.”
Self-Protected Combination Motor Controllers
Self-protected combination motor controllers are often called self-protected combination controllers, Type E starters, Type E combination starters, or self-protected starters (SPS). SPSs are intended to provide motor overload per 430.32 and motor branch-circuit short-circuit and ground fault protection per 430.52 by combining a magnetic short-circuit trip and adjustable motor overload in one package. SPSs are a listed combination starter suitable for use without additional motor branch-circuit short-circuit and ground fault protection but limited to only single motor circuits.
SPSs have additional test requirements for low level short-circuit interrupting tests followed by endurance tests that are not required for other combination motor controllers. SPSs can be either manual (Type E) or electro-mechanical (Type F – include a load side contactor for electrical operation). SPSs are often marked with a slash voltage rating that indicates the device is limited to use only on solidly grounded wye type systems. When marked with such a slash rating, they cannot be used on ungrounded, corner-grounded or impedance-grounded systems. Creepage and clearance on the line terminals has to be the same as UL 489 and UL 98 devices. Because of this, SPSs are often listed and marked for use with a terminal kit which is required to be installed to ensure line-side terminal spacings are adequate for the application. Additional accessory parts, such as lockable handles, may need to be used as an SPS. SPSs are suitable for use as a motor branch-circuit disconnect or "at the motor” disconnect per NEC 430.109, as a motor controller (On-Off Function) per NECArticle 430, Part VII, and as both a motor branch-circuit disconnect or "at the motor” disconnect and motor controller per NEC 430.111.
Figure 5: Example of SPS with required spacing adapter accessory.
SPSs, as listed to UL 508, will contain a marking near the agency symbol. This marking should read "Listed Self-Protected Combination Motor Controller” for factory assembled units. If separate components (accessories) are required, the manual self-protected combination motor controller must be marked "Self-Protected Combination Motor Controller when used with (manufacturer and part number of load side component)” or "Motor Controllers Marked For Use With This Component”. If not marked with manufacturer and part number, the other components of the assembly must be marked, "Suitable For Use On The Load Side Of __(B)__Manual Self-Protected Combination Motor Controller, or the equivalent, where (B) is replaced with the manufacturers name and part number of the manual self-protected combination motor controller.” In addition, SPS which are limited in application to only solidly grounded wye type systems will be marked with a slash voltage rating such as 480Y/277 or 600Y/347.
Figure 6: Example of SPS motor controller label
Use of busbar systems
Busbar systems are very commonly used with both MMPs and SPSs. The challenge with using busbar systems with devices applied as SPSs is that only the incoming terminals of the first device use feeder terminals that comply with the feeder circuit spacing required by UL 508A and the listing requirements of the device. The adjoining SPSs are not able to use the standard spacing adapters as marked and required to achieve adequate feeder circuit spacing in order to be applied as SPSs and at the same time allow installation of the busbar as shown in Figure 7.
Because of this issue, the author recommends only using the busbar accessories in group motor installations (where the devices are being applied as MMPs). A group motor application is considered a branch circuit application and feeder circuit spacing is only required on the line side of the branch circuit overcurrent device, not the MMPs. However, when applied in this manner, the additional requirements perNEC 430.53 or UL 508A 31.4 must be met.
Figure 7: Example of use of busbar systems
Protection of non-motor circuits
SPSs are only permitted to be used in single motor applications. They cannot be used as the branch-circuit protective device for a group motor application or branch circuit protection of other loads, such as lighting, heating, transformers, etc., unless they are listed to UL 489. Some manufacturers do provide products called motor protection circuit breakers which are evaluated per UL 489 (which look like a typical molded-case circuit breaker with an adjustable overload setting) and are suitable for branch circuit protection of all types of loads.
How are MMPs and SPSs applied?
As mentioned previously, the biggest challenge for these devices is to open an industrial control panel and answer the question: is a device being applied as an MMP or SPS? The author recommends analyzing the application of the device as an MMP first.
For a single motor, this is a simple question: is there a suitable motor branch-circuit short-circuit and ground-fault protective devices upstream (fuse or circuit breaker)?
For a group motor application, it becomes more complicated. In this case the user must verify the MMP is suitable for group motor applications: (1) is it protected by a motor branch circuit short-circuit and ground fault device (fuse or circuit breaker) that does not exceed the rating marked on the MMP for group applications, and (2) the tap rules are met per the NEC 430.53 or UL 508A (1/3rd or 1/10th rule discussed previously).
If the device cannot meet these requirements for group motor applications, then the user must look at adding needed accessories to apply the device as an SPS. Because of this, the user is likely recommended to avoid using busbar systems. Finally, the user must revise the ratings (typically go from 480V to 480Y/277V) for the device and assembly. Additional marking requirements are required per UL 508A when used as an SPS.
Assembly Marking Requirements
When a device is used with a slash rating, such as 480Y/277V, NEC 430.83(E) must be considered. Basically this section of the NEC allows the device to be applied only on a solidly grounded wye system. Therefore, it can only be installed on a solidly grounded 480Y/277V system. It cannot be applied on a 480V ungrounded or corner-grounded system or a 480Y/277V resistance grounded system. Section 49.6 of UL 508A would additionally require the industrial control panel to be marked 480Y/277V, as opposed to 480V. In addition, section 54.12 would require an additional marking on the input terminals of "For use on a solidly grounded wye source only.”
Additionally, if a device is being applied as an SPS, section 55.7 of UL 508A requires cautionary markings to the assembly. An industrial control panel provided with an SPS shall be marked:
With the word "WARNING” and the following or the equivalent: "To maintain overcurrent, short-circuit, and ground-fault protection, the manufacturer’s instructions for selection of overload and short circuit protection must be followed to reduce the risk of fire or electric shock.”
With the word "WARNING” and the following or the equivalent: "If an overload or a fault current interruption occurs, circuits must be checked to determine the cause of the interruption. If a fault condition exists, the current-carrying components should be examined and replaced if damaged, and the integral current sensors must be replaced to reduce the risk of fire or electric shock.”
Read more by Daniel R. Nesser
MMPs and SPSs can be cost-effective and space saving devices for use in industrial control panels. However, when using these devices, care must be taken to assure these devices are being applied properly per their listings. Often these devices are best applied as MMPs to take advantage of the use of accessories, such as busbar systems, higher voltage ratings, and reduced marking requirements. When used in a group motor installation, the group motor installation requirements must be followed. If used as an SPS, additional accessories, inability to use busbar systems, voltage limitations and special marking requirements are important application considerations.