Posted By David Young,
Thursday, March 01, 2007
Updated: Sunday, February 10, 2013
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Electric utility rates vary greatly from utility to utility and from state to state. To protect your and your company’s wallets, it is very important to understand the rates by which you are being charged for electricity. The cost of electricity is so high that some commercial and industrial companies have entire departments whose sole responsibility is to study the utility rates and make load management recommendations for saving money. The work of these departments pays for itself many times over.
Load management is changing the way a company or household operates electrical devices to save money. I am not talking about just turning off lights when not needed. Yes, that does save money. What I am talking about is operating electrical equipment during off-peak hours when the cost of electricity is cheaper. I will explain off-peak and on-peak when I get into the actual rates in part two of this series. Unlike most consumables, the cost of electricity varies with the time of day, day of the week and month of the year.
Most companies just have someone pay the bill and do not realize for what they are paying. To give you an idea of what I am talking about, I want to share a true story with you. While working in the engineering department of a large electric utility, I was often asked by the marketing department to talk to customers with technical questions. In one such occasion, I was asked to talk to a commercial customer about the company’s electric bills. The customer was questioning why the electric bills at their 20,000 square foot warehouse suddenly had doubled. At the request of the customer, the utility had already checked the accuracy of the metering.
I asked the customer if there had been any recent changes to the facility. They said they had added a mezzanine, a partial second floor, within the warehouse so they could store more material. They expected some increase in their electric bill since additional lighting was installed under the mezzanine, but they did not expect their bills to double. They had a twenty-four-hour, seven-day- per-week operation. The building was not heated or air-conditioned. They said their only electrical load was the lighting.
We walked around the facility and stepped into the elevator to go up to the mezzanine— yes, a large elevator capable of lifting a fully loaded fork truck. They had forgotten about the elevator in our discussion of new loads. Though there was a staircase to the mezzanine level, they used the elevator even for pedestrian use. I asked them about the capacity of the elevator and the frequency of use. They said they only used it about a dozen times per day. Since the elevator was only on for a few minutes each time they operated it, they could not imagine how it would increase their electric bill significantly.
I sat down with them and explained the electric rate by which they were being billed. They were being billed an energy charge for the number of kilowatt hours (kWh) of energy they consumed and a demand charge for the maximum amount of power in kilowatts (kW) they used. Demand is how much power is being used by the electrical loads at any instant in time. If you were trying to decide what size generator to purchase to supply all the power for a facility, you would have to know the maximum demand of the facility. Fortunately for the customers of most utilities, utilities do not charge for the maximum demand. They usually charge for the maximum one-hour or fifteen-minute demand. For some utilities, the maximum one-hour demand is the maximum average demand for any rolling one-hour period. Some utilities use a clock hour. In this case, a commercial company can save a lot of money, for example, if they have a compressor that has to be on half the time, they operate it from half past the hour to half past the next hour. The resulting one-hour demand for the compressor is then half of what it would be if operated randomly.
Maximum fifteen-minute demand is the maximum average demand usually for any rolling fifteen-minute period. The maximum fifteen-minute demand is usually less than the peak demand and the maximum one-hour demand is usually less than the fifteen-minute demand. If the load is constant, all three demands are the same.
In the case of the 20,000 square foot warehouse, the demand was constant prior to the addition of the elevator. With the addition of the elevator, the demand charge had gone through the roof. I found out that though the elevator was used only a few times each day, they usually operated it several times in a fifteen-minute period. The demand charge was based upon the maximum fifteen-minute demand and, therefore, it went up.
They asked what they could do to reduce the cost. Since the lifting height limit of their fork trucks would permit lifting pallets to the mezzanine level, one of my suggestions was to remove a ten-foot-wide opening in the mezzanine wall and use the fork trucks to lift pallets directly to the mezzanine level. They could use a small walk-behind fork truck to move the pallets around on the mezzanine level. If they had to stack pallets on the mezzanine, they would have to keep a regular fork truck on the mezzanine.
With this scenario, I suggested they lock the elevator controls in the off position. I received a call from the president of the company about six months later. He was very happy with the lower electric bills and he thanked me for my assistance. At that point, he felt the cost of the elevator had been a waste. He was not happy with the elevator company and the electrical contractor for not warning him of the effect the elevator would have on the electric bills.
Next time, in Part 2, I will get into the details of typical electrical rates and how you can save money with load management both at home and on the job.
Read more by David Young
Posted By James W. Carpenter,
Thursday, March 01, 2007
Updated: Sunday, February 10, 2013
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The holidays are over and the stress of getting just the right gift for that special someone, of fighting the crowds at the stores, and wondering if the money will last is finally over. Now just the stress of paying the bills as they come in is on us. But was it not worth it to see the happy faces of the children and/or the grandchildren? Now it’s back to the regular grind. But it doesn’t have to be a regular grind. This year, 2007, should be an exciting year for us all. A new National Electrical Code will be published. New learning opportunities will abound— new challenges to meet and conquer, and a whole year to do those things that we have been putting off.
IAEI and its members will have many opportunities to get involved in many wide-ranging activities from educational opportunities at seminars, chapter, division, and the annual section meetings, to supporting the association by getting new members and encouraging present members to get in and stay active. Your International Office has already been hard at work in many different areas. Preparing for the 2008 Analysis of Changes is well underway. We have several updating projects under way. Study guides have been updated to the 2005 edition of the NEC and should be available in the first quarter of 2007. The One- and Two-Family Dwelling Electrical Systems book based on the 2005 NEC and the 2006 IRC will be available in March 2007. Seminars are being planned and scheduled for 2007 on various timely subjects. New ways of presenting subject material are being planned to compliment our standby classroom style of presentation. Distance learning, taking continuing education courses on the internet, will be expanded through IAEI’s and UL’s joint program on UL University. Our new codes and standards specialist, Mike Weitzel, has added to the productivity of the Education Department. As a result, the Publication Department’s staff has been under increased pressure to turn around the material for publication. They continue to do their high quality work.
The International Office finished 2006 under an existing membership software system that was being phased out, and started 2007 with a new system from another supplier. The changeover went smoothly, which is surprising since our online membership, ordering, and event registering were off-line for several weeks. The staff had to be trained, so during the first week of January 2007 you may have had difficulty getting to a staff member. We apologize for the difficulty but, hopefully, now things are even better than before. The services provided for you by the International Office are growing and more exciting things are being planned.
As IAEI and you continue into 2007, I would like to expand on my editorial in the January/February issue of the IAEI News. Last issue I asked for you to reflect on why you were in the electrical industry. This time let’s explore why you are a member of the International Association of Electrical Inspectors. In a survey that we did last year several comments from people were noted. They were comments such as:
- IAEI does an outstanding job of educating the electrical industry, particularly the electrical inspector. if you think education is expensive, try ignorance.
- I have been a member since 1956, and IAEI has been an important part of my career.
- The organization has helped me in my career.
- Good association for promoting the field
- Information from articles in the IAEI News.
- Of course, not all comments were complimentary to IAEI but that gives us areas to improve.
I asked last time for you to tell us your story about the reasons you are in the electrical trade. Now you should add to that story why you are a member of IAEI and what it means to you.
Each time the International Board of Directors, the Executive Committee, or the International Membership Committee meet, a discussion always takes place on how to present the benefits of membership to the public. More difficult for them is to identify those benefits. Everyone has different benefits that he or she considers most important. So how about at the next chapter or division meeting that you ask your fellow members what they consider as benefits of membership. Then let the International Office know. We can then better serve all the electrical industry.
Maybe most will cite IAEI’s participation in the development of codes and standards, representing the association among the electrical industry and the public, or collecting, interpreting, and disseminating information on subjects related to the profession. One caller recently told me that he wanted to join IAEI because his insurance agent told him that he could get better rates if he belonged to associations like IAEI. That, in itself, may not be an accurate reason to join IAEI, but if the member takes advantage of the benefits and opportunities to better himself, then certainly he or she would be a lesser risk for the insurance company. Whatever your reasons are, write them up and let us all know.
Read more by James W. Carpenter
Posted By Leslie Stoch,
Thursday, March 01, 2007
Updated: Sunday, February 10, 2013
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The Canadian Electrical Code defines a grounding electrode as: "a buried metal water-piping system or metal object or device buried in, or driven into, the ground to which a grounding conductor is electrically and mechanically connected.” In other words, it’s whatever metal objects the code allows you to drive into or bury in the earth and use for grounding electrical systems. The requirements for grounding electrodes up to 750 volts are found in Rule 10-700. This rule has been substantially rewritten in the 2006 Canadian Electrical Code.
Rule 10-700 of the 2006 CE Code opens by listing three different types of grounding electrodes, manufactured, field-assembled and in situ grounding electrodes that form a part of an existing infrastructure (for example a building). The rule provides several new definitions and an expansion in the number of permissible options for establishing a grounding electrode. Unfortunately, the new rule also may produce some new areas of possible confusion, since some parts of the rule are less prescriptive than in the past.
Manufactured grounding electrode, Rule 10-700(2)
Subrule 2(a) —A manufactured grounding electrode may consist of two ground rods, spaced no closer that 2 m apart, bonded together and driven full length into the earth. Except for some new verbiage, nothing much has changed here.
Subrule 2(b) —As before, it may also consist of an approved plate electrode buried in the earth, at least 600 mm below finished grade or encased in the bottom 50 mm of a concrete slab that is in direct contact with the earth, and not less than 600 mm below finished grade. A plate electrode must provide at least .2 square m surface area in contact with the earth. Once again, nothing has changed.
Field assembled grounding electrode Rule 10-700(3)
Subrule 2(a) —A field-assembled grounding electrode may consist of a bare copper conductor at least 6 m long, sized in accordance with Table 43 and installed in the bottom 50 mm of a concrete footing or foundation and not less than 600 mm below finished grade. This has sometimes been referred to as a "ufer ground,” named for the person who dreamed up the idea. Once again nothing has changed.
Subrule 2(b) —A bare copper conductor at least 6 m long, sized in accordance with Table 43 and buried in the earth at least 600 mm below finished grade is a brand-new alternative now permissible in the 2006 CE Code. The American National Electrical Code provides a similar option, but in the form of a "ground ring” surrounding a building and installed underground.
In situ grounding electrode
Rule 10-700(4) just specifies that an in situ grounding electrode is not considered electrical equipment, must be located at least 600 mm below finished grade and have a surface exposure to earth equivalent to a manufactured grounding electrode. The rule doesn’t say it must be metallic (but of course we knew this from the original definition in Section 0). This grounding selection is new and not specifically spelled out.
When we turn to Appendix B, we find that an in situ grounding electrode must have a surface area in contact with the earth at least as great as that of a manufactured grounding electrode. A helpful hint in Appendix B tells us that the necessary specifications for manufactured grounding electrodes may be found in the CSA Standard C22.2 No. 41 – OK if we all have access to this document.
Appendix B also provides a number of examples for in situ grounding electrodes including:
- An underground metal water system at least 600 mm below finished grade and extending at least 3 m beyond the building foundation, which has traditionally been recognized as a suitable grounding electrode; or
- And this is brand-new — the reinforcing steel of concrete slabs, foundations and pilings or metal pilings in contact with the earth and at least 600 mm below finished grade. Obviously, building reinforcing steel and steel pilings treated against corrosion would be unsuitable for use as grounding electrodes.
How does one determine that the requirements of the rule are met for the examples provided in Appendix B? No doubt the CSA standard does provide some data in the form of minimum metal surfaces required to be in contact with the earth. But how easily can we relate this data to the surface areas of different diameters and lengths of piping and building reinforcing steel? It seems to me that the electrical inspection authorities should work out the equivalencies and provide some guidelines to help reduce the inevitable number of uncertainties.
As with previous articles, you should always refer to the electrical inspection authority in each province or territory for a more precise interpretation of any of the above.
Read more by Leslie Stoch
Posted By Underwriters Laboratories,
Thursday, March 01, 2007
Updated: Sunday, February 10, 2013
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Question: UL code correlation database
I see that the 2006 White Book now includes an index that correlates the 2005 NEC to UL product categories, is there a UL code correlation database online that I can access?
The answer is yes; there is a UL code correlation database on UL.com. In the past several issues of the UL Question Corner, we discussed all the new features in the 2006 UL White Book that make it the companion tool to the NEC. One of those features is the Index of Product Categories Correlated to the 2005 NEC, the index is a code correlation index. UL took that data and incorporated that into an online version in a database form that correlates the 2005 NEC to UL product categories and also includes various building, mechanical and gas codes. If you are an electrical or a multi-discipline inspector, this database will be a onestop shop for determining which UL Listed products you should be looking for to determine compliance with the Code.
The UL Code Correlation Database is located on the Regulators page of UL.com by clicking on the UL Code Correlation Database button on the right hand side of the screen. The database can also be directly accessed atwww.ul.com/regulators/codelink.
The Code Correlation Database covers the following model codes: 2005 National Electrical Code (NEC), 2000, 2003 and 2006 International Building Code (IBC), UL Online Model Code Correlation Database 2003 and 2006 International Mechanical Code (IMC) and the 2003 and 2006 International Fuel Gas Code (IFGC). In the near future, the 2006 International Fire Code will also be added.
The database is simple to use:
1. Select the Model Code you would like to search from the drop down menu.
2. Enter the Code Section you are searching for or the UL Category Code. By entering the code section, you will see the UL product categories that apply to the specific code section. If you enter a UL category code instead of a code section, all the code sections will be shown that have been identified as pertaining to that category code.
In addition to the identification of the proper UL Product Category and Category Code, you will also be provided with the additional details, such as the identification of the standard that is used for certification and a link to the scope of the UL standard if applicable.
This database will be a big help to AHJs, plan reviewers, specifiers and designers by bringing a direct link between the Code and code-compliant product installations.
Let’s take an example of how it works. Suppose we are trying to locate transfer equipment for use in optional standby systems for NEC 702.6. First, locate the Model Code Correlation Database atwww.ul.com/regulators/codelink, then select the 2005 NEC from the Model Code pull down menu, then enter the Code Section 702.6 in the Code Section Number field and click submit.
The results show there are five UL product categories that may satisfy this Code requirement. Those are: Panelboards (QEUY), Enclosed Switches (WIAX), Automatic Transfer Switches for use in Optional Standby Systems (WPXT), Non Automatic Transfer Switches (WPYV), and Transfer Switches (WPTZ).
While the transfer switch categories may be obvious for compliance with Article 702, Panelboards (QEUY) and Enclosed Switches (WIAX) may not be so obvious. By clicking on the details link and then the Guide Information link for Panelboards (QEUY), we see that the Guide Information includes information regarding Article 702. This information states, "Some panelboards, constructed with interlocked main switching and overcurrent protective devices, have been investigated for use in optional standby systems in accordance with Article 702 of the NEC and are marked ‘Suitable for use in accordance with Article 702 of the National Electrical Code ANSI/NFPA 70,’ or, if provided within kit form, ‘Suitable for use in accordance with Article 702 of the National Electrical Code ANSI/NFPA 70 when provided with interlock kit Cat No. ____.’”
If we click on the details link for Enclosed Switches (WIAX) and then the Guide Information link we see the (WIAX) Guide Information also includes information regarding Article 702 suitability. The Guide Information states, "Some panelboards, constructed with interlocked main switching and overcurrent protective devices, have been investigated for use in optional standby systems in accordance with Article 702 of the NEC and are marked ‘Suitable for use in accordance with Article 702 of the National Electrical Code ANSI/NFPA 70,’ or, if provided within kit form, ‘Suitable for use in accordance with Article 702 of the National Electrical Code ANSI/NFPA 70 when provided with interlock kit Cat No. ____.”
The UL Model Code Correlation Database is just another tool UL provides to AHJs and installers to assist in determining code-compliant installations. If you have any questions on the UL Model Code Correlation Database, please contact Bob Eugene at Robert.Eugene@us.ul.com.
UL Question Corner
Posted By Michael Weitzel,
Thursday, March 01, 2007
Updated: Sunday, February 10, 2013
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Typically, when length is a factor in the installation, so is voltage drop. A variety of installations may involve feeders or branch circuits of considerable length. These include such installations as industrial plants; airports; tollway, highway, turnpike or street lighting; electrically controlled irrigation machines (also known as center pivot irrigation machines); installations on docks, marinas, or boatyards; farms or ranches; and commercial, residential, or governmental structures. Electrical designers and installers as a whole are generally aware of the requirements in 210.19(A)(1), and fine print note (FPN) No. 4 that provides explanatory material relating to voltage drop for feeders and branch circuits and suggests the maximum percentage of voltage drop which will provide "reasonable efficiency of operation,” should not exceed 5% at the farthest outlet where power is required. Some regard and apply the information as a requirement of the Code, and others may ignore it because they figure, Hey, it’s not mandatory text, so it’s no big deal if I do it or not.
Generally, switchboards and panelboards will function with voltages that are slightly lower than standard nominal ratings with no ill effects to them. Utilization equipment, however, such as lighting, computer-data processing equipment, electronic equipment, and motors may malfunction or be severely damaged by under-voltage conditions. One important thing to consider is the manufacturer’s instructions that are included with the listing and labeling of the product. Even though both 210.19(A)(1) FPN No. 4 and 215.2(3) FPN No. 2 suggest percentages for maximum allowable voltage drop which will provide reasonable efficiency of operation for utilization equipment, Section 110.3(B) requires all listed and labeled electrical equipment to be installed and used in accordance with the manufacturer’s instructions included with the product’s listing and labeling. Nearly all electrical equipment and materials that are installed and used today are listed, labeled, and include installation instructions.
For example, in an outdoor area lighting installation such as those at sports complexes and so forth, luminaires (lighting fixtures) rated for operation at 240 volts ac, nominal, may have manufacturer’s instructions included with the product that permit an operating voltage of no less than 228 volts for proper operation. A 5% voltage drop from 240 volts nominal is 228 volts (240 V x .95 = 228 V), and meets the minimum voltage allowed per the manufacturer. A drop in voltage of more than 5% will cause the luminaires to malfunction. Utility system distribution voltages typically are regulated to be kept within a certain bandwidth, normally plus or minus 2% of nominal system voltage for the end user. In some parts of the country, utilities may generate and distribute voltages that may be as much as 4% higher than the nominal system voltage (240 V x 1.04 = 249.6 V). This slight variation of higher voltage is favorable to the designer/installer of electrical systems, helps with voltage-drop concerns, and will generally not harm utilization equipment, but cannot be counted on. It is wise to install electrical systems to a worst-case scenario and account for some slight drop in voltage, as distribution system loads may increase and power source feed locations may change in time. The point to remember is that electrical installations must meet at least the minimum requirements of the Code, and 110.3(B) is definitely one of the requirements that cannot be ignored.
Enter Article 250
Sizing electrical ungrounded (hot) and grounded (neutral) conductors for voltage drop is a necessity for the proper functioning of electrical equipment and as a requirement of the Code. However, equipment grounding conductors must also be considered for a properly functioning and code-compliant feeder or branch-circuit installation. These conductors are an essential part of a safe electrical installation, as they protect people and property from injury or damage.
Proper Sizing of Equipment Grounding Conductors for Voltage-Drop Situations
Of course, equipment grounding conductors (EGCs) may be installed in the form of busbars, metal raceways, or be considered as the outer metal sheath of cables of one type or another in accordance with 250.118, Types of Equipment Grounding Conductors, and other applicable Code rules. EGCs also may be in the form of solid or stranded, insulated, covered or bare wire type conductors. For simplicity and illustration, wire type conductors will be addressed in this article.
Generally, with few exceptions, all feeders and branch circuits require some sort of EGC. Feeders and branch circuits of extended length are required to have an EGC that will perform per 250.4(A)(5), and qualify as a "permanent, low-impedance circuit facilitating the operation of the overcurrent protective device or ground detector for high-impedance grounded systems.” Safety hazards to life and property are created when feeders or branch circuits are run a long distance and the EGCs are undersized when a ground fault occurs a long distance from the source of power. The overcurrent protective device may not see nor clear the fault, and the ground-fault current may endanger persons or damage property.
When ungrounded and grounded (neutral) conductors are run a long distance and are required to be increased a percentage above the standard size conductor in order to function properly, per Section 110.3(B), manufacturers’ or listing agencies’ instructions, EGCs must be increased in size also as they may be needed and must be ready to carry fault current to open an overcurrent device [also see 250.122(B)].
The minimum sizes for EGCs are found in NEC Table 250.122. The note at the bottom of the table requires that "where necessary to comply with 250.4(A)(5) or (B)(4), the equipment grounding conductor shall be sized larger than given in this table.” Section 250.122(F) applies where conductors are run in parallel. Individual EGCs and those installed in parallel must comply with the note at the bottom of Table 250.122.
Sample Voltage-Drop Calculation
This example is given as an illustration to resemble a real-world voltage drop scenario, and emphasize some items to consider when long runs of electrical feeders or branch circuits may be necessary or cannot be avoided. Installations including all conductors within the same cable(s) are commonly used; however, raceways are discussed here; though for simplicity, raceway sizes are not mentioned.
Obviously, as conductor sizes are increased, raceway sizes may need to be increased. Voltage drop for branch circuits and cable installations is reserved for another article, though most information here would apply. The load for the feeder has already been calculated per Article 220. Other real-world concerns such as customer preference, the cost and availability of conductors and electrical equipment such as large transformers, or installing a high-voltage feeder using overhead spans of smaller conductors are all factors that designers and installers must consider when designing any installation.
Figure 1. 2000-amp, 208Y/120V-feeder, distance = 1500 feet long
Example: A proposed 2000-amp 208Y/120 V feeder will be 750 feet long (for a total length of 1500 feet to the load and back) in its maximum length (including all branch circuits); have 5) 600 kcmil copper conductors per phase installed in non-metallic conduit (5 x 420 amperes = 2100 amperes), include a 1/0 grounded (neutral) conductor in each raceway (the neutral load has been sized per 220.61 at 620 amperes), (5 x 150 amperes = 750 amperes), and a required minimum equipment grounding conductor size of 250 kcmil to be installed in each raceway per Table 250.122 and Section 250.122(F). For our example, all conductors are copper, and their ampacities are taken from the 75°C column of Table 310.16 for THWN conductors (see figure 1).
The questions are, Are all conductors properly sized to account for voltage drop? and Are the proposed equipment grounding conductors adequate to facilitate the operation of the overcurrent device per the requirements in 250.4(A)(5)?
Utilizing the voltage drop/circular mil formula found on page 136 of volume 2 of Ferm’s Fast Finder, 2005 edition, for three-phase circuits for the ungrounded conductors:
(18.7 is known as the "K” factor, a value assigned for the resistance of a conductor at a certain temperature per foot rated to the circular mil size. Other examples of the use and calculation of the K factor are given in Ferm’s Fast Finder).
If the wire size of the ungrounded conductors is increased to 700 kcmil each:
If the wire size of the ungrounded conductors is increased to 750 kcmil each:
If the wire size of the ungrounded conductors is increased to 800 kcmil each:
If the wire size of the ungrounded conductors is increased to 900 kcmil each:
If the wire size of the ungrounded conductors is increased to 1,000 kcmil each:
If the wire size of the ungrounded conductors is increased to 1,250 kcmil each:
The grounded (neutral) 1/0 copper THWN conductors are rated at 150 amperes, and are 105,600 cm in size per chapter 9, Table 8, Conductor Properties. 105,600 cm x 2.08 (208%) = 219,648 cm, which is not a standard size conductor. The closest size above that value is 250 kcmil copper, (250,000 cm). One 250 kcmil grounded (neutral) conductor must be installed in each of the paralleled raceways.
Table 250.122 specifies the minimum size EGC for a 2000-amp feeder or branch circuit as 250 kcmil. 250,000 cm x 2.08 (208 %) = 520,000 cm. Again, chapter 9 Table 8, Conductor Properties, is consulted, and the closest size is 600 kcmil copper, which is required to be installed in each of the paralleled raceways.
Note: The original minimal size required by Code was 250 kcmil, but because of the long distance (1500 ft) of the feeder, a much larger EGC is required; in this case, over twice the original size, as a minimum.
Remember, the EGCs must be increased in size by the same proportion as the ungrounded conductors, per 250.122(B).
At this point, it is important to mention that provisions must be made for terminating these larger conductors in switchboards, panelboards, disconnect switches, or other electrical equipment. Manufacturers’ instructions, per 110.3(B), must be consulted, as well as the requirements in 110.14 for terminations, 312.6 for wire bending space, and space for installing, bending, and termination of all conductors. Large junction or splice boxes, indoor or outdoor termination enclosures, or wireways—any of which may contain power distribution blocks or similar devices—may be required at each end of the system in order to transition from a larger conductor size to account for voltage drop to/from a size that will terminate in the equipment and meet all Code requirements. Buss gutters may also be considered for use. Raceway, wireway, or auxiliary gutter fill, junction or pull box sizes, and all other applicable Code rules must be considered as part of the design work and prior to installation.
Sometimes transformers are used to step up the voltage in long feeders in order to reduce the size of the feeder conductors in the long run. In this case, a transformer would be necessary at both ends of the feeder as shown in figure 2.
The same feeder installed at 480Y/ 277 volts would be sized this way:
The load on the grounded (neutral) conductor for the feeder now rated at 480Y / 277 volts is:
In accordance with Table 310.16, 700 kcmil copper conductors paralleled twice (460 amperes x 2 = 920 amperes) are the minimum size required to serve the load. However, per 240.6, the next standard size overcurrent protective device size above 868 amperes is 1000 amperes, and the conductors are required to be sized per the overcurrent device size at a minimum. Table 310.16 indicates that 900 kcmil THWN copper conductors paralleled two times = 1,040 amps, and would be code-compliant for the installation; but with the long distance of the feeder, we must verify that all conductors are sized large enough to be code-compliant and properly sized to serve the load, including the grounded (neutral) conductor. The minimum size grounded (neutral) conductors sized per 310.4 as a minimum 1/0 copper (installed in parallel in each non-metallic raceway) = (150 amperes x 2 = 300 amperes), which under normal conditions would meet the requirements for the 269 amperes capacity for the conductors. The minimum size EGC—again required to be installed in each paralleled non-metallic raceway—per 250.122(F) must be verified for proper sizing. Generally, the minimum size EGC for a 1000 ampere feeder per Table 250.122 is 2/0 copper.
The calculation for the ungrounded conductors is as follows:
Because of the requirements of 240.6, the ungrounded conductors were increased in size from 700 kcmil to 900 kcmil copper. This is a 29% increase in size, and the grounded (neutral) conductors and equipment grounding conductors must be increased by the same proportion, per 250.122(B). For the 1500-foot distance of the feeder, because the voltage is higher at 480 volts (as opposed to 208 volts), the amperage of the load is less.
The minimum size grounded (neutral) conductor permitted to be installed in parallel is 1/0, in accordance with NEC 310.4. Each grounded conductor must be increased 29% to account for voltage drop, the same as all other conductors of this feeder. A 1/0 copper conductor = 105,600 cm x 1.29 (129%) = 136,224 cm. Based on chapter 9, Table 8, Conductor Properties, 136,224 cm is not a standard size conductor. From this table, you will find that the next larger size found is 3/0, which is 167,800 cm in size. A 3/0 copper grounded (neutral) conductor is then required to be installed in each of the two paralleled non-metallic raceways for this feeder.
The calculation for the grounded conductor is:
The minimum size EGC for a 1000-amp feeder is 2/0 copper, which must be increased in size by a minimum of 29%. The question is, How many circular mils (cm) in size is a 2/0 copper conductor? The answer is found in chapter 9, Table 8, Conductor Properties. From this table, find that a 2/0 conductor is 133,100 cm in size. 133,100 cm x 1.29 (129%) = 171,699 circular mils. This is not a standard size conductor. Note that the next higher and closest size is a 4/0 conductor, sized at 211,600 cm (circular mils). A 4/0 copper EGC is required to be installed in each of the two paralleled non-metallic raceways for this feeder.
Figure 2. The same feeder as figure 1, except now at 480Y/277V with step up and step down transformers to account for voltage drop
Once again, it is important to remember that the Code is not a design or specification manual, but it is a minimum standard for electrical installations.
In this article, we have discussed the voltage-drop requirements found in the NEC, illustrated the use of a formula for determining the amount of voltage drop on a long feeder or branch circuit, some items to consider when designing electrical installations that include the termination of long runs of conductors, and the proper sizing of equipment grounding conductors for installations where voltage drop is a factor.
Electrical installations must meet at least the minimum requirements of the Code. While the FPN following Section 210.19(B) and FPN No. 2 to 215.2(3) are explanatory material and not mandatory, 110.3(B) is definitely one of the requirements which cannot be ignored, and does apply relating to the voltage drop of conductors that supply utilization equipment.
Read more by Michael Weitzel
Posted By Michael Johnston,
Monday, January 01, 2007
Updated: Sunday, February 10, 2013
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Equipment installed in electrical systems generally is required to be grounded. There are some specific exceptions that relax this general requirement of the NEC; but, for the most part, electrical equipment and the normally non-current-carrying metal (conductive) parts of equipment are to be grounded.
Photo 1. Large electrical feeder circuits are often installed using the provisions for parallel conductor installations contained in 310.4 of the Code.
The performance requirements for equipment grounding are provided in Section 250.4(A)(2) for grounded systems, and 250.4(B)(1) for ungrounded systems. This article focuses primarily on the equipment grounding conductor requirements for grounded systems, although they are essentially the same for both grounded and ungrounded systems. Part VI of Article 250 provides the prescriptive rules relating to equipment grounding conductor installations. The requirements in this part of Article 250 provide information about the requirements for equipment to be grounded, types of equipment grounding conductors, sizes of equipment grounding conductors, identification of equipment grounding conductors and connection methods.
The Need for Parallel Conductors
Photo 2. Electrical feeder conductors installed in parallel, supplying a large panelboard
Often in electrical design and installations, there is a need to install feeder conductors in parallel. Where feeders are large in size and ampacity, they quickly reach a point where it becomes impractical to install them using only one conductor per phase and one for the grounded (neutral) conductors. This is where the provisions for feeder conductors installed in parallel come into play. The Code requirements for parallel conductors are provided in 310.4 and the requirements for equipment grounding conductors for parallel conductors are covered by 300.3(B)(1), 310.4, and 250.122(F) [see photo 2]. This article provides a closer look at the requirements for equipment grounding conductors in general, but specifically those equipment grounding conductors for larger feeders installed using parallel conductors.
Rules for Conductors Installed in Parallel
The rules pertaining to electrical conductors installed in parallel are provided in 310.4 of the NEC. Before reviewing the general requirements for conductors installed in parallel, let’s look at what constitutes conductors installed in parallel.
Copper, copper-clad, or aluminum conductors in size 1/0 or larger are permitted to be installed in parallel. This includes the ungrounded phase conductors, conductors of different polarity, grounded neutral conductors and grounded phase conductors. The provision recognizes that multiple conductors can be installed in parallel with one another not to create one conductor, but to create one electrically conductive path (see figure 1). In other words, conductors installed in parallel are electrically connected at both ends creating an electrically conductive path capable of carrying a desired ampacity based on the needs of the design (see photos 1 and 2). Paralleled conductors of each phase, polarity, neutral, or other grounded circuit conductors must meet all the following requirements:
- They must be the same length
- They must be terminated in the same manner
- They must have the same conductor material
- They must be the same size in circular mil area
- They must have the same insulation type
Figure 1. Conductors are installed in parallel to create one larger electrically conductive path, not one conductor.
Where conductors are installed in separate cables or raceways, the raceways or cables are required to have the same physical characteristics, and the same number of conductors in the parallel set must be installed in each raceway. The equipment grounding conductors installed with parallel conductor installations must also meet all requirements above, except for the sizing requirement of 1/0 minimum. The sizing requirements are based on the rules in 250.122(F). These sizing rules are reviewed in detail later in the article.
General Circuit Conductor Installation Requirements
Where equipment grounding conductors are installed with paralleled feeder conductors, the requirements in 310.4 have mandatory application. To develop an understanding of the requirements in 310.4 and 250.122(F), a brief review of the rules in 300.3(B) and 250.134(B) is in order. The requirements in these sections call for all conductors of the circuit, including any grounded conductors and all equipment grounding conductors, to be installed together, typically contained in the same raceway, cable bus assembly, cable tray, trench, cable, or cord. This requirement serves to maintain low impedance levels during normal conditions and abnormal (ground-fault) conditions. To separate the equipment grounding conductors results in increases in inductive reactance, which raises impedance levels. This is one of the primary reasons for installing equipment grounding conductors in each raceway when they are installed in multiple raceways. Under ground-fault conditions, the equipment grounding conductor carries the heavier level of fault current until the overcurrent device opens and clears this event from the system. If there is only one equipment grounding conductor in one of the raceways of the parallel set, the impedance is raised significantly due to inductive reactance. Not installing equipment grounding conductors in each raceway or cable not only violates 250.122(F), but also 300.3(B) and 250.134(B). Of course, any of the equipment grounding conductor types identified in 250.118 can be used for parallel conductor installations. The sizing requirement pertains only to installations where wire-type equipment grounding conductors are installed.
Equipment Grounding Conductor Types
Photo 3. Electrical metallic tubing used as an equipment grounding conductor for a feeder made up of conductors installed in parallel
Section 250.118 provides a long list of acceptable equipment grounding conductors that qualify as an effective ground-fault current path where installed in accordance with all other applicable requirements of the NEC. This section recognizes wire-type equipment grounding conductors as either copper or some other corrosion resistant conductor. It also lists conduit, metallic tubing, metallic cable assemblies, and other acceptable equipment grounding conductors. Where metal conduit is used as the equipment grounding conductor, it must meet the requirements in 110.12 for workmanship, supporting and securing requirements in chapter 3 for the particular wiring method used, and they are required to be of the same physical characteristics as provided in 310.4 (see photo 3).
Sizing Parallel Equipment Grounding Conductors
Figure 2. All conductors of the circuit including any grounded conductors and equipment grounding conductors are required to be grouped together in accordance with 300.3(B).
Where electrical conductors are installed in parallel and are all contained in the same raceway or other enclosure such as a wireway or auxiliary gutter, the sizing rules for equipment grounding conductors of the wire-type are quite simple. Just use the rating of the overcurrent device protecting the parallel set and reference Table 250.122 for the minimum size single equipment grounding conductor of the wire-type. Where equipment grounding conductors are installed with conductors in parallel, and they are in separate multiple raceways or cable assemblies, the wire-type equipment grounding conductors are required to run in parallel in each raceway and must meet all the requirements in 310.4 with the exception of the sizing rules (see figure 2).
Photo 4. Paralleled equipment grounding conductor connections at equipment
The equipment grounding conductors for parallel runs do not have to meet the requirement of 310.4 that calls for a minimum 1/0 conductor size, because the equipment grounding conductors in each raceway are full size as required by 250.122. The equipment grounding conductors in a parallel installation are not being installed in parallel to create one larger conductive path , as is the case for the ungrounded phase conductors of the circuit and grounded (neutral) conductor if present. See 250.122(F) and 310.4 for the exact Code language that provides this requirement.
Sizing Equipment Grounding Conductors
Figure 3. Sizing requirements for equipment grounding conductors installed with feeder conductors in parallel
Sizing rules for equipment grounding conductors installed with parallel runs of conductors are provided in 250.122(F). The equipment grounding conductors installed in separate multiple raceways or cables must be sized based on the rating of the overcurrent device protecting the parallel set of conductors in accordance with Table 250.122 (see figure 3). This means if the overcurrent protective device for a feeder is rated at 800 amperes, the size of equipment grounding conductor (wire-type) cannot be less than 1/0 copper or 3/0 kcmil aluminum or copper-clad aluminum.
Question No. 1: If the size of the overcurrent device protecting a feeder is rated at 1600 amperes, what is the minimum size aluminum equipment grounding conductor (wire-type) required in each raceway of the parallel set?*
Section 250.122(B) also includes a requirement that addresses conductors that are increased in size, such as for voltage drop. Where equipment grounding conductors (wire-type) are installed with conductors in parallel that are installed in separate raceways and increased in size for voltage drop reasons, the equipment grounding conductors must all be increased in size proportionately (see example 1).
Equipment Grounding Conductor Connections
Figure 4. Equipment grounding conductor connections for a grounded system
Equipment grounding conductors are an important component in the effective ground fault current path. One of the most critical points in any electrical circuit is the terminals or connections. This is typically the point at which a circuit failure would occur. The Code requirements for equipment grounding conductor connections are covered in 250.130. This rule addresses the required connections at a separately derived system or service. For a grounded system, the equipment grounding conductor is required to be connected to the grounded conductor and the grounding electrode conductor at the service or at the source of a separately derived system as provided in 250.30(A)(1) (see figure 4). The same rules apply for an ungrounded system, except that there is no grounded conductor in an ungrounded system. In this case, the equipment grounding conductor is connected to the grounding electrode conductor and the enclosure (see figure 5).
Figure 5. Equipment grounding conductor connections for an ungrounded system
Section 250.8 provides more specific requirements for grounding and bonding conductor connections. This section requires that these connections be made using listed lugs, listed pressure connectors, listed clamps, or other listed means (see photos 4, 5, and 6). This is one of those NEC rules that specifically requires the use of listed equipment.
There is additional information about listed grounding and bonding equipment in the Guide Information for Electrical Equipment (UL White Book) under category (KDER). Another key requirement is found in Section 250.12. Where painted or coated enclosures are installed to which equipment grounding conductors must be connected, the coating is required to be removed to ensure electrical continuity and conductivity, unless the connections are made by using fittings designed to make coating removal unnecessary.
Photo 5. Equipment grounding conductor connections made by listed lugs
The equipment grounding conductor of the grounding and bonding scheme in any electrical system has two primary functions. First, it serves to establish an earth (ground) connection for the equipment. This maintains the equipment at or as close as possible to earth potential. The second function of the equipment grounding conductor is to provide an effective ground-fault current path to facilitate overcurrent device operation during ground-fault events. Where equipment grounding conductors are installed in parallel, the requirements in 250.122(F), 310.4, 300.3(B) and 250.134(B) all apply.
Photo 6. Equipment grounding conductor connections made at a panelboard supplied by a feeder installed with conductors in parallel
Equipment grounding conductors of the wire-type installed in parallel conductor runs must be sized based on the rating of the overcurrent device protecting the parallel set in accordance with Table 250.122. The minimum 1/0 sizing requirement for conductors installed in parallel does not apply to equipment grounding conductors, but all other installation requirements contained in 310.4 apply to those wire-type equipment grounding conductors. The information provided in this article is based on the minimum requirements contained in NEC-2005. As always, be sure to verify with the local authority having jurisdiction for any local rules that may also apply to parallel conductor installations.
* Answer: 350 kcmil aluminum or copper clad aluminum
Read more by Michael Johnston
Posted By Tim Owens,
Monday, January 01, 2007
Updated: Sunday, February 10, 2013
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In September 2001, New York was horrified by the destruction of the World Trade Center due to terrorist activities. In July 2005, New Orleans was heavily damaged by flooding from broken dikes resulting from Hurricane Katrina. In October 2006, Hawaii was rocked by numerous earthquakes. In November 2006, the Pacific Northwest was inundated by flooding from massive rains. In November 2006, North Carolina was damaged by tornadoes. All of these disasters had one thing in common—Expectations!
The people affected by these disasters expected immediate response by appropriate personnel and restoration of normal activities within a reasonable time. They expected police and fire operations to protect them and their property, that their electricity, gas, water, and sewer would operate for their survivability, and that their banks would provide money for food and other essentials.
These expectations of a quick response require continuity of operations by the police, fire, and emergency medical personnel. In addition, the second layer of disaster response also requires a continuity of operations for hospitals, electrical power, communications, and other essential services. This need for continuity of operations has long been part of planning by federal, state, and municipal governments as well as the business community. However, especially after the terrorist attacks on the World Trade Center, concerns arose over the ability of certain infrastructure facilities to survive man-made disasters or even natural disasters. The first attempt to address these concerns in the building code arena is the proposed new Article 585, Critical Operations Power Systems, for the 2008 National Electrical Code (NEC).
How Did Article 585 Come About?
The Department of Homeland Security (DHS) has spent considerable time and effort in assessing the needs of the United States for protection against terrorist’s attacks. DHS is also accountable for the response to natural disasters through the Federal Emergency Management Agency (FEMA). One of the concerns raised during these assessments was the ability of a community’s emergency response system and related infrastructure to withstand natural and manmade disasters. These concerns were relayed to the National Fire Protection Association (NFPA) which created a Task Group on Emergency and Standby Power Systems for Homeland Security.
This Task Group met in August of 2005 with the mission of reviewing the NEC-2005 and other NFPA documents to identify where the current minimum requirements do not adequately address the level of integrity to withstand disasters. In addition to the NEC-2005, the Task Group also reviewed the provisions of NFPA 1600–2004 edition, Standard on Disaster/Emergency Management and Business Continuity Programs; NFPA 110–2005 edition, Standard for Emergency and Standby Power Systems; and NFPA 111–2005 edition, Standard on Stored Electrical Energy Emergency and Standby Power Systems.
The first question the Task Group tried to answer was exactly what constitutes a critical operations facility. It is important to remember that this task group met in August 2005 during the Hurricane Katrina disaster in Louisiana which provided stark examples of failures in communications and public infrastructure. Another point to remember is that there is currently no comprehensive definition or listing of those facilities that could be considered as critical operations occupancies. The Task Group created a listing of possible critical operations facilities that included uses such as air traffic control centers, hazardous material handling operations, emergency communication needs, medical operations, and police, fire, and other critical public works operations. It was also discussed that many business continuity operations are considered critical to the public’s ability to withstand disasters including financial institutions, radio and television stations, and data storage operations. This list became the proposed fine print note (FPN) Number 2 to Article 585.1 Scope.
The Task Group’s next question to answer was exactly what electrical systems were required for these critical operations facilities and how to provide sufficient reliability for continuity of operations in these facilities. This question consumed the most time spent in the actual Task Group meeting as well as the follow-up emails and telephone conference calls. The discussion about this question covered the types of hazards that could arise from the naturally occurring events—such as earthquakes, hurricanes, floods, fires, and blizzards—to human caused events—such as bombings, chemical attacks, biological agents, or nuclear devices. The results of this discussion became the proposed FPN No. 6 to 585.1, Scope. Additional discussions covered the required installations of the electrical system and how best to provide survivability of the system during or immediately after disasters. This discussion eventually resulted in the language of the proposed new article for the NEC-2008.
The Task Group’s submittal, authored by Alan Manche with the Square D Company, to the NEC Technical Correlating Committee (TCC) became Proposal 20-1 Log Number 3497 for inclusion of a new article and annex within the NEC-2008. In the Task Group’s substantiation for this new article it was noted that these are "minimum requirements for those electrical systems where continuity of power and operation of systems is paramount.” The NEC TCC created a new code-making panel (CMP) 20 to handle the proposal for Article 585, Critical Operations Power Systems, and Annex H, Availability and Reliability for Critical Operations Power Systems; and Development and Implementation of Functional Performance Tests (FPTs) for Critical Operations Power Systems. The members of the NFPA Task Group were included in the membership of CMP-20 as well as other technical individuals to insure a broad-based review of the proposal.
CMP-20 met for three days in January of 2006 to discuss Proposal 20-1. Discussion covered the original work of the NFPA Task Group on critical operations facilities and their required electrical system requirements. The result of these discussions was an Accept in Principle in Part action on Proposal 20-1. The NFPA Regulations Governing Committee Projects defines Accept in Principle in Part as accepting the proposal with a change in wording in parts of the proposal. CMP 20’s action is explained in the following excerpt of the panel statement to its action on Proposal 20-1:
"In addition to editorial changes, for clarity and style manual compliance, the panel has made technical revisions to the recommended text for the purposes of providing enforceable (sic), prescriptive requirements for the installation and operation of a highly reliable power system for the operation of a mission critical facility. Additionally, there are two proposed annexes intended to provide useful design information.”
With this action by the panel and pending any additional action during the NEC-2008 Report on Comments meeting held in December 2006, a new Article 585, Critical Operations Power Systems, a new Annex F, Availability and Reliability for Critical Operations Power Systems; and Development and Implementation of Functional Performance Tests (FPT’s) for Critical Operations Power Systems, and a new Annex G, 585.60 Supervisory Control and Data Acquisition (SCADA) will be included in the NEC-2008.
What is Article 585?
The layout of Article 585, Critical Operations Power Systems (COPS), is listed below.
585.3 Application of Other Articles
585.4 Risk Assessment
585.5 Physical Security
585.6 Testing and Maintenance
II. Circuit Wiring and Equipment
585.10 Feeder and Circuit Wiring
585.11 Branch Circuit and Feeder Distribution Equipment
585.12 Feeders and Branch Circuits Supplied by COPS
585.14 Wiring of HVAC, Fire Alarm, Security, Emergency Communications, and Signaling Systems
III. Power Sources and Connection
585.20 Sources of Power
585.22 Capacity of Power Systems
585.24 Transfer Equipment
585.30 Branch Circuits Supplied by COPS
IV. Overcurrent Protection
585.52 Ground-Fault Protection of Equipment
V. System Performance and Analysis
585.64 Emergency Operation Plan
General Information about COPS
As with any other article contained within theNEC, the Scope and Definition Sections provide invaluable information. For Article 585, 585.1, Scope, provides the basis for the application of this new article. There are two paragraphs both of which are important reading. The first paragraph states:
The provisions of this article apply to the electrical installation, operation, monitoring, control, and maintenance of critical operations power systems consisting of circuits and equipment intended to supply, distribute and control electricity to designated vital operations in the event of disruption to elements of the normal system.
CMP-20 placed language in the scope section that expands upon any previous language used in the NEC. Not only does the Scope cover installation, operation, and control of systems but it also requires monitoring and maintenance of these systems. CMP-20 understood that the systems being proposed within this Article 585 are a step above any other system in the NEC due to the increased need for reliability and survivability. CMP-20 acknowledged that current NEC language, most notably in Articles 700, 701, and 517, has provisions for continued operations in non-normal situations, however, Article 585 situations must provide for continued operations under much more severe conditions and for a longer period of duration than those other articles envisioned. Thus, CMP-20 conceded that in addition to installation, operation and control requirements there must be some monitoring and maintenance requirements implemented to insure that the critical operations facilities continue to operate in periods of extreme crisis.
The second paragraph of the scope section follows: "Critical operations power systems are those systems so classed by municipal, state, federal, or other codes, by any governmental agency having jurisdiction or by facility engineering documentation establishing the necessity for such a system.”
This paragraph clearly indicates that Article 585 will not delve into the designation of critical operations facilities but relegates that designation to entities. CMP-20 accepted that the authority or need for designation of critical operations facilities is outside of the scope of the NEC as this designation is more appropriately performed in the building code arena. In order for Article 585 to perform as intended, there must be facilities built stronger than normally required by current building codes to protect the actual physical critical operations function.
In addition to governmental needs, CMP-20 granted that the requirements of Article 585 lend themselves to the needs of the business community for continuity of operations. Disasters not only affect individuals but also businesses. For many businesses, it is vital that their operations continue under any circumstances. Thus, the last part of the second paragraph gives business entities the ability to document the need for classification of there facilities as requiring a COPS installation.
There are two definitions contained in Section 585.2 that need mentioning in understanding the requirements of Article 585. The first is critical operations power systems (COPS). Power systems for facilities or parts of facilities that require continuous operation for the reasons of public safety, emergency management, national security, or business continuity.” This language clearly indicates that Article 585 is intended for continuity of operations beyond the requirements in Articles 700, 701, and 517 for life safety. The definition also indicates that COPS is for a whole facility or a part of the facility. This part of a facility could be as large as the entire building or as small as a single room. The NEC will not limit the area of a site that can be designated as requiring COPS.
The second definition is designated critical operations areas (DCOA). Areas within a facility or site designated as requiring critical operations power.” This definition indicates that COPS is intended to supply a designated area and not just a single function. Article 585 is closer in concept to Article 517, Health Care Facilities, a designated area, rather than Article 700, Emergency Systems, wiring for a function. Again, CMP-20 relegated the designation of DCOA to governmental agencies or business entities and not the NEC.
One other section of Article 585 that bears mentioning is 585.4, Risk Assessment. This is a vital requirement within Article 585 as it communicates the necessity for examining the types of hazards or conditions that COPS must meet. This takes into consideration that the NEC cannot provide requirements to meet all climatic, geological, topographical, or human-caused events. This section is an expansion of Section 90.5(B), Adequacy, which states that the NEC "contains provisions that are considered necessary for safety … but not necessarily efficient, convenient, or adequate for good service.” As stated in 585.4(C), a strategy must be created for mitigation of the hazards not addressed by the NEC. This takes into account that hazards present in Florida may not be present in California or in Maine. Thus, Article 585 gives minimum requirements but does not cover all possibilities.
COPS Wiring and Equipment
Part II of Article 585 provides requirements for the installation and protection of the actual COPS wiring. The underlying theme here is that COPS wiring requires a higher level of physical protection than current language for emergency systems wiring. Specifically, COPS wiring must remain completely isolated from all non-COPS wiring and may not serve any loads not associated with the DCOA. All COPS feeder wiring must be physically protected by installation in rigid metal conduit, intermediate conduit, Type MI cable, schedule 80 rigid non-metallic conduit, or concrete encasement of schedule 40 rigid nonmetallic conduit, flexible nonmetallic or jacketed metallic raceways, or jacketed metallic cable assemblies listed for installation in concrete. In addition, COPS feeders must be listed electrical circuit protective system with a minimum 1-hour fire rating, be protected by a fire-rated assembly listed to achieve a minimum fire rating of 1 hour, be embedded in not less than 50 mm (2 in.) of concrete, or be a cable listed to maintain circuit integrity for not less than 1 hour when installed in accordance with the listing requirement. Wiring below the 100-year floodplain level must be suitable for wet locations.
COPS branch circuit wiring installed outside of the DCOA must be installed to the same requirements as feeder wiring. This provision does not apply to branch circuit wiring inside the DCOA which suggests that the wiring methods in NEC chapters 1 through 4 is permissible.
Finally, the COPS feeder distribution equipment must be located in spaces with a 2-hour fire rating and above the 100-year floodplain level. COPS branch circuit distribution equipment must be located with the DCOA that those branch circuits supply.
COPS Power Sources
Power sources for COPS are covered in Part III of Article 585. A power source in addition to the normal power source must be supplied for COPS. This additional power source must be installed in spaces fully protected by approved automatic fire suppression systems or in spaces with a 1-hour fire rating. The power source shall be installed as a separately derived system and grounded as required in NEC 250.30. This additional power source may be storage batteries, a generator set, an uninterruptible power supply, or a fuel cell system. Whatever the power source, it shall have the ability to carry the required loads, may supply other loads if selective load pickup, load shedding, and peak load sharing are present, and shall be capable of continuous operation for a minimum of 72 hours.
The concept expressed in this part of Article 585 is that an on-site second source of power be provided for continuity of operations in the DCOA. Also expressed is the idea that this second power source must last for a minimum of three days. The understanding by CMP-20 is that fuel resupply may not be readily available.
COPS Overcurrent Protection
There are three requirements of Article 585, Part IV, COPS overcurrent devices. The first restricts access of overcurrent devices to authorized personnel only. This requirement pertains to the physical security necessary for DCOA access. The second requirement addresses ground-fault protection for personnel by requiring an additional level of protection beyond that required in Section 230.95 or Section 215.10. This requirement attempts to prevent a ground-fault in a non-COPS feeder from causing a loss of power to COPS. The final requirement is for coordination of overcurrent devices. This should result in a fault being cleared at the lowest level overcurrent device possible.
System Performance and Analysis
Part V of Article 585 addresses the need for a documented emergency operations plan. This requirement goes towards the reliability and maintainability of COPS and the DCOA. This plan must address the actual operations during an emergency and the recovery of normal operations. This requirement will ensure that a comprehensive operational plan is in place to provide the continuity of operations expected for the critical operations function.
Benefits of Article 585
Article 585 is the first attempt to answer the response problems resulting from naturally occurring and human-caused events. DHS realized that the level of reliability of the emergency response infrastructure within the United States did not meet expectations. Additionally, concerns were raised over the ability to continue vital operations during and after these events. NFPA replied to these concerns by creating the Task Group on Emergency and Standby Power Systems for Homeland Security. This Task Group created a proposal for inclusion of a new article within the NEC-2008. The NEC TCC created CMP-20 to review the submitted proposal. CMP-20 worked during January 2006 and December 2006 to refine the proposal into a working part of the NEC-2008. Upon a vote by the membership at the upcoming 2007 NFPA Annual Meeting in Boston, Article 585 will become an official part of the NEC-2008.
Article 585 addresses the reliability and continuity of operations for those facilities, or parts thereof, that have been designated as critical to the operations of municipal, state, federal governments as wells as certain business operations. The article performs this function by requiring a document risk analysis of the particular event the facility may experience. An emergency operations plan is also created to insure continuity during and after the event. The wiring of this facility is then installed to preclude failures resulting from these events.
The benefit that will be realized from the application of the requirements contained in Article 585, Critical Operations Power Systems, is that naturally occurring or human-caused events should not cause a total collapse in the public infrastructure or a cessation of business activities. The goal of Article 585 is to save lives and protect property.
Read more by Tim Owens
Posted By Philip Cox,
Monday, January 01, 2007
Updated: Sunday, February 10, 2013
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A combination of traits and associated technical training and experience should help produce an individual highly qualified in the profession of electrical inspection. When one is truly professional as an electrical inspector in both conduct and performance, he or she not only brings greater respect to the industry but also makes it easier for other members of the electrical community to do their jobs.
What are the guidelines for determining whether a person is a good electrical inspector? Qualifications for becoming an electrical inspector vary greatly. Some jurisdictions may not require an individual to have any electrical training or experience before being hired as an inspector. Others require a minimum of journeyman or master electrician license, formal degrees in electrical engineering, or years of field experience. While there may not be an established list of qualifications one can use to determine if a person is qualified to be an electrical inspector, there are some characteristics which are very important for doing the job.
The level of commitment of an inspector becomes evident within a short period. When a person neither believes in the job nor is committed to its objectives, it can usually be recognized. The job of an electrical inspector is too important to be left in the hands of one who is interested only in putting in forty hours a week. The responsibility of helping provide for safe electrical installations for those living within the inspection jurisdiction is too serious to ignore. Fortunately, many dedicated electrical inspectors go beyond the required job responsibilities and give much needed service both to the public and to the industry. The demand upon an electrical inspector’s time is generally not limited to a 40-hour week. Most successful electrical inspectors spend a lot of time after normal work hours teaching classes, giving presentations to groups, answering electrical code questions and doing other things to help improve his or her community.
Thirst for Knowledge
The higher one climbs on the ladder of knowledge, the better one can see. The horizon is broadened and many things can be seen more clearly. It is refreshing to see inspectors who love to talk code at every opportunity, read extensively, attend educational forums and participate in other related electrical inspector activities. The training and skills necessary to be a good electrical inspector do not come quickly or easily. One must work hard to gain an acceptable level of expertise and be very diligent about staying proficient. The thirst for knowledge is a motivating force that drives many individuals to go beyond what is required and to do what is necessary in order to become the best they can be.
Approaching the responsibility of enforcing electrical safety rules with a positive attitude is beneficial for all affected parties. This is often reflected by the inspector projecting an image of working to verify compliance with established safety rules rather than having a negative attitude of trying to find something wrong with a job. Listening to an inspector talk with a contractor or engineer provides good insight into the attitude the person has in relation to the job. An important point that needs to be kept in mind is that to see a job done correctly, the electrical inspector should work with installers, designers and manufacturers’ representatives, etc., but for the consumer or general public. While the responsibility for the tone of a discussion often rests on the shoulders of the inspector, the other person must bear responsibility as well. Where the other individual’s opinion is so firmly established that no amount of persuasion can change it and where emotion overrides logic, the inspector’s efforts to explain a rule or its application are not likely to succeed. The ability to maintain a positive level of communication is very difficult in these circumstances. Often the use of an established appeal process is necessary to resolve the issue in these circumstances.
Fairness in Applying the Code
Rules should be interpreted and applied uniformly to all involved. The inspector is a type of law enforcement official and, as such, has the responsibility of enforcing both the letter and intent of the adopted law. Those who make up their own rules, or enforce provisions for which there is no established law, or make decisions in direct conflict with adopted rules should seriously reconsider potential repercussions of those actions. There have been occasions where people have complained of unfair and unequal enforcement when, in fact, the work was not in conformance with the electrical code and the inspector was simply doing a good job. In order to guard against problems in this area, inspectors should work very hard to ensure there is not even a hint of uneven enforcement.
Designers and installers have a greater level of confidence in the electrical inspector when they know he or she is very capable of inspecting a job, evaluating its compliance with safety code rules, and making sound judgments on field conditions. The decisions inspectors often must make can dramatically impact the affected parties, and the responsibility for making those decisions is a heavy load to bear. For this reason, an inspector must not only have an excellent knowledge of applicable code rules but also must understand the electrical system. Some people discount the importance of requiring inspectors to have a good working knowledge of the fundamental principles of electricity, but that knowledge is necessary for understanding how a system operates and how it will be affected by specific conditions. Understanding installation methods is also important. Unless one has worked in the trade, it is more difficult to comprehend field situations fully and to evaluate them according to written rules. Without field experience, it is more difficult to see the whole picture.
Consistency in interpreting and applying electrical code rules is very significant to users of the code. Whenever an installer does electrical work within an inspection jurisdiction, rules should be applied the same to all jobs regardless of which inspector looks at the installation. This is a serious challenge for chief electrical inspectors and supervisors. When an inspection department consists of a large number of inspectors, establishing and maintaining a common level of understanding of code rules and enforcement procedures is difficult. Inconsistencies in situations sometimes occur because of rules in the National Electrical Code that are not precise in nature. An example of this is 230.2(B)(2). This provision permits more than one service to a single building or other structure that is sufficiently large to make two or more services necessary and where special permission is given. For consistency, both the guidelines on how to determine what constitutes a "sufficiently large” building or other structure that justifies the use of 230.2(B)(2) and where the use of "special permission” is necessary should be clearly understood and applied by the authority having jurisdiction. If it is left up to individual inspectors to interpret this rule without any established policy or guidance, undesirable inconsistencies could easily occur. Without basic guidelines to determine what constitutes a large building or other structure covered by 230.2(B)(2), individual inspectors may have widely different opinions on the matter. It should be clear to both inspectors and installers as to how a rule is applied.
Every inspector has to make judgments in the field because of conditions or situations that do not clearly fall under a code rule. The inspector should consider all aspects of the situation before making any decision on this type of matter. Consideration should be given to how the decision impacts the job being inspected as well as other jobs. In addition, how it will affect all parties involved and how it relates to the purpose of the NEC in "… the practical safeguarding of persons and property from hazards arising from the use of electricity” is important [90.1(A)]. There is no substitute for an inspector’s good judgment in evaluating electrical installations and applying code rules. Section 90.4 provides needed flexibility for inspectors. This provision assigns the responsibility of interpreting the code, approving materials and equipment, granting special permission and allowing alternate methods to the authority having jurisdiction. Every job does not neatly fit into conditions described by the Code. Neither is it practical to write code that will cover every variation that could possibly occur. When the flexibility covered in 90.4 is used, it should be done with proper regard for the gravity of the responsibility.
Common Sense Approach
There are those who apply electrical code rules strictly by the letter and there are those who enforce both by the letter and by intent. This may appear confusing to some, but inspectors need to understand the reasons behind safety rules and to enforce them in a logical manner. Rules properly interpreted and applied in a logical manner will provide a good level of safety. An example is the application of the term wrenchtight where following rules for bonding. The rule does not specify the type of wrench, the amount of pressure to be applied, or any specific details or conditions. To skilled installers and inspectors, this term is readily understood as to its intent. Qualified inspectors who understand both the letter and intent of the code are familiar with electrical products and installation methods, know the difference between wrenchtight as applied to a run of 3/4-inch conduit from that for a run of 6-inch conduit. If one interpreted wrenchtight to allow the use of any type of wrench, the selected tool may very well be inadequate to do the job. A wrench used to tighten a threaded coupling on a small diameter raceway may not be appropriate to tighten a coupling on a 4-inch conduit, even though the wrench may be adjustable to grip the larger conduit. The purpose and intent of the code are very much a part of the enforcement of electrical safety rules.
One characteristic that most inspectors demonstrate is dependability. This involves keeping one’s word and being reliable. In turn, because inspectors traditionally feel strongly in this area, they expect those they associate with to live by the same standards. During visits to some inspection jurisdictions, it became readily evident in many cases that not only contractors but also the inspector’s superiors had a high level of trust in the electrical inspector’s ability and conduct. They apparently were very confident that the inspector would do what was needed, and they could depend upon it being done in an acceptable fashion.
The Ability to Listen
Listening properly can solve many problems and help eliminate misunderstandings. Being able to communicate effectively is a skill vital to a professional electrical inspector. When people enter into conversations with their minds made up, or do not want to hear what is being said, there is little chance of solving problems. The inspector is frequently involved in discussions with manufacturers, designers, installers and property owners. In order to understand specific needs or positions taken by others, one should listen to what is said, have an open mind on the matter, digest that information and evaluate the situation without bias. The term listen cannot be over emphasized. It is a learned skill in most cases and takes a disciplined level of concentration. A significant problem in oral communications is the failure to listen closely to what is said and to hear the entire point being made before making a decision or reaching a conclusion. One has only to listen to discussions between people to learn that some individuals prematurely and incorrectly form an opinion in response to what another person says. It is best to wait until the entire statement or point is made before trying to interpret what is being said.
The Ability to Work With People
One can be the best technically qualified person available and still be a relative failure as an electrical inspector. Whether one realizes it or not, the inspector must be able to communicate effectively with people in order to succeed. In reality, it is one of the most important skills for an inspector. It is difficult to deal with an individual during a hostile confrontation. It takes a lot of patience and understanding to work out this type of situation effectively. One can expect these situations to arise from time to time because of the very nature of law enforcement. Misunderstandings, differences of opinions and many other factors result in conflicts with inspectors. The effectiveness of the inspector can depend a great deal upon his or her ability to solve these problems. Unfortunately, if these confrontations cannot be resolved, the inspector may end up with an adversarial form of enforcement. In some cases, the situation is not realistically within the inspector’s ability to control and that the level of antagonism is established by the other party. Where the inspector does all he or she can to approach a difficult situation in a professional manner and the other party continues to be confrontational, that individual must be held responsible for his or her conduct. Fortunately, where inspectors use the professional approach, the latter situation is less likely to occur.
Responsible Use of Authority
Inspectors must have the proper tools to do their job. A necessary part of that set of tools is the authority to act and enforce rules and regulations adopted by the inspection jurisdiction. The type and extent of authority granted to an electrical inspector is dependant upon a number of factors and may vary from that in other jurisdictions. Some inspectors may have the authority to take actions such as having violators arrested or stopping work at a job site while others may be far more limited in what they can do. It depends upon the enforcement policy adopted by a jurisdiction. Regardless of the type of authority an inspector has, he or she is expected to perform with a high level of integrity. How an inspector applies that power tells a lot about how that person views his or her role and what standard of ethics that is practiced. In many cases it also reveals a lot about those who are responsible for the conduct of inspectors. Most people within the industry have probably heard of an inspector being accused of abusing authority. Unfortunately, those rare few are the ones who get the headlines while the overwhelming majority of honorable ones who uphold the law go unrecognized. In every profession there are those who enjoy using their authority to cause others to do their bidding. Possibly this is an ego boost and it causes them to have an inflated view of themselves that others do not share. There is no room in the inspection profession for this type of person. There is too much at stake. Unethical inspectors hurt the inspection industry but they also affect the general public.
Read more by Philip Cox
Posted By Wayne Lilly,
Monday, January 01, 2007
Updated: Sunday, February 10, 2013
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By the time this article is printed, my year as international president will have ended. Brenda and I thank each of you for your kindnesses during the section meetings. My time working through the chairs at the chapter, section and international levels has given me friends that I will cherish all my life and has afforded me countless learning opportunities. It has provided me with an appreciation of the hard work done by the leadership throughout IAEI and taught me what it means to be part of an organization dedicated to high standards and goals that are meant to serve the best interest of our fellowmen. I want especially to thank those three people who first introduced me to IAEI and mentored me: Byron Powell, David Miller and Melvin Young.
I spoke to some 1200 people at the section meetings, but know that many members were not able to attend. For those, here is a summary of my speech:
I want thank each member of the IAEI for your membership.
Because you are a member, IAEI will be able to participate in the present and future safe use of electricity.
Because you are a member, we will be able to continue to develop, offer and monitor exceptional programs for certification so that the best-qualified people can demonstrate their abilities.
Because you are a member, we will be able to participate directly in the writing of numerous electrical safety documents that make our homes and businesses safe places to live, work and play.
Because you are a member, you have a voice that represents you. Every time IAEI meets with organizations such as ICC, NFPA, CSA, NECA, IBEW, UL and IEC your interests are voiced.
Because you are a member, we are able to participate in online training sites such as ULUniversity.com.
Because you are a member, we will be able to continue to have representation on numerous committees, to present training and information that is as good as any in the industry, to offer the best in technical publications and articles and to expand our role for your benefit.
Because you are a member, our children and grandchildren will enjoy the safe use of electricity.
The future of electrical safety depends on people being involved. Every day there are people and organizations, even governments, who are attempting to make the electrical business less safe. They tell us such things as self-certification of equipment is safe or that spot inspections are just as good as complete and full inspections and that certification of contractors and inspectors is not necessary.
IAEI is dedicated to and is actively supporting electrical safety. It supports good codes and good laws that promote that safety. Perhaps you want to become involved with IAEI. If you think that one voice is just a small noise that is unheard in the wilderness, join IAEI and let that voice be added to many so that it can be heard above the noise. If you think that working for the safety of our families, our loved ones and our children and grandchildren is important, then work together with IAEI to make it happen. If you want to make a difference, then join IAEI.
If you look at IAEI and are not interested in joining, then for goodness sake get involved with some other organization that actively supports and fosters safe electrical systems. Electrical safety is far too important to ignore. At some point in life we find ourselves reminiscing about the past. I would like to walk down memory lane with you, going all the way back to 1960. I was 13 years old. There was a presidential election in full swing in the United States, the first election I remember much about. One of the reasons it remains in my memory was the black and white television set in my parent’s living room. It brought the election right into my home. I was impressed with the grandeur of the conventions. Even the debates were exciting.
I cannot recall many of the specifics of the election, but the inaugural address by the newly elected president still stands brightly in my memory. I can still see him, in my mind, standing at the microphone, dressed in a business suit. When he spoke, it was cold enough that you could see his breath. He was very young, but also very old as there were age lines beneath his eyes. What he had to say was not the standard political line of the day. He called upon each of us to stand up, take hold of life and give it a shake.
If you do not recognize who that president was, you will probably recognize the most remembered sentence from that address. "Ask not what your country can do for you, but what you can do for your country.” John F. Kennedy spoke those words with conviction.
Those words are still true today. They are a constant reminder of how we should live our lives. We should be dedicated to the concept of what we can do for others rather than what others can do for us. I know that is not what we are bombarded with day after day. It seems that everything from jean advertisements to health care insurance is aimed at self. They tout what we can get. They promise instant gratification.
Now we know that which has true worth and meaning does not come easily or instantly. It takes hard work and dedication, and it takes commitment.
I am going to ask you a question, and I hope it will make you think: "Why are you here?” Not in some vast cosmic sense; but rather, Why are you at this IAEI meeting?
I have asked myself that question many times, and the answer varies. Maybe the answer is to further my knowledge, or to meet old friends. Sometimes it is to get a couple of days away from work and the boss. Maybe, just maybe, it is to help others. Whatever your answer is, give some thought to the challenge from John F. Kennedy as it relates to your attendance at an IAEI meeting.
People often ask what IAEI can do for them. The answer is, quite a lot. IAEI offers many advantages to membership, such as a truly outstanding magazine, educational programs, unique certification programs, quality publications, direct input into the writing of safety documents, an opportunity for each member to have direct input into electrical safety documents, an opportunity to express your views to others and networking with others.
Those are excellent reasons for joining IAEI. However, there is a reason that far outweighs them, and that is reflected in John F. Kennedy’s challenge. That reason is service to your fellowmen. Service by participating in and supporting an organization dedicated to helping others stay safe and stay alive.
Within IAEI, you can find plenty of opportunities to serve. There are lots of committees, programs to produce, seminars to sponsor, training to give and educational programs for the general public. Be a participant. Be a provider. Be a helper. If you are unsure what you can do, ask someone. Make a commitment to IAEI. Be more than a semi-warm body sitting in the room. Give up that "I’m only one small person and I can’t change anything” attitude. Take a chance! Make something happen! IAEI has true worth and meaning. Its goals are worthy of pursuit. It does deserve commitment. I hope, in some small way, that I have challenged you to be a part of something bigger than you are. If I might be so bold as to steal some language from John F. Kennedy, "Ask not what IAEI can do for you, but what you can do for IAEI.”
Read more by Wayne Lilly
Posted By Jesse Abercrombie,
Monday, January 01, 2007
Updated: Sunday, February 10, 2013
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Last year, more than 670,000 businesses opened their doors, according to the U.S. Small Business Administration. In fact, hundreds of thousands of people set up their own shops every single year. If you’re considering startling your own electrical contracting or inspection firm, you’ve got a lot to be excited about, and you may be prepared to make large sacrifices to help your business succeed. But there’s one sacrifice you don’t have to make: your financial security.
Unfortunately, many business owners pour their entire lives’ savings into making their new ventures succeed — and that’s probably a big mistake. If you were a senior project manager for a great company and had a six figure retirement, don’t use those assets to start a new business. When you start up a business, you are already taking on a degree of risk, but you don’t need to jeopardize all your plans for the future.
So, before you launch your business, try to follow these basic guidelines:
- Build an emergency fund. Make sure you keep at least six months worth of living expenses available in some type of liquid account, one that is completely separate from your business accounts. If you need to pay for a major fleet repair, deal with rising copper prices or cover a major medical bill, you’ll want to be prepared. And if you can’t pay for these items, your business will likely suffer, too.
- Review your insurance coverage. Do you have enough life insurance to pay off your home and educate your children if anything happens to you? If not, you’ll want to upgrade your coverage. You also might want to add a mortgage protection benefit to your life insurance policy, so that you can keep up your house payments if you become disabled and can’t run your construction business for a while. Disability insurance may also be valuable, though you’ll need to shop around for a reasonably priced policy, as this coverage can be expensive.
- Set up a retirement plan. If you worked at a large electrical company before striking out on your own, you might have contributed to a 401(k) or other employer-sponsored retirement plan. But now that you’re the business owner yourself, you’ll have to set up your own retirement plan. Fortunately, many good plans are available. For example, if your business has no employees except you and your spouse, you can choose a SEP IRA, an owner-only 401(k) or an "”owner-only”" defined benefit plan. If you’e going to have employees, you might want to explore a SIMPLE IRA or a Safe Harbor 401(k). All these plans have both advantages and limitations; to find the one that’s right for you, meet with a financial professional who is experienced in helping small-business owners.
- Choose the correct ownership structure. As a small-business person, you could be a sole proprietor, you could form a partnership or you might set up what’s known as an S corporation. The ownership structure you choose can have a big effect on some important issues, such as whether your health insurance premiums are tax deductible. Consequently, you may want to consult with your tax advisor before making a decision as to which route you will follow.
By following the above suggestions, you should be able to focus more intently on those tasks that can help you grow your electrical business. So, before you make the "jump,” plan ahead. You’ll be glad you did.
Read more by Jesse Abercrombie