Question 1. Which authority rules in the situation where a UL-approved equipment skid and local codes clearances appear to be in conflict? In this case, a pump skid has a disconnect over the pump discharge outlets. Once the pipes have been installed, you have to stand over the pipes to access the disconnect. The skid is approved as an assembly of pumps, tank, and disconnect. — C.G. Answer 1. First, let me say that I am not totally clear as to what is meant by “which authority rules?” Generally, if the local jurisdiction or area has legally adopted the National Electrical Code, then Section 90.4 prevails. Section 90.4 states that “The authority having jurisdiction for enforcement of the Code has the responsibility for making interpretations of the rules, for deciding on the approval of equipment and materials, and for granting the special permission contemplated in a number of the rules.” Typically, a jurisdiction or area has only one authority having jurisdiction (AHJ), so that person legally rules.  Second, we should note that Underwriters Laboratories does not approve equipment. UL is a product testing lab (i.e., nationally recognized testing laboratory) — they test products and equipment for safety. If the product or equipment complies with the appropriate safety standard, it is acceptable for listing and labeling by the testing lab. Listing and labeling is one of several methods for the AHJ to determine the acceptability of products or equipment for installation and use. Now, regarding the skid — NEC 110.26 requires that sufficient access and working space be provided and maintained about all electric equipment. This is a general rule. The access and working space are to allow for the safe operation and maintenance of the equipment. In addition, NEC subsection 110.26(A) has requirements where the equipment is “likely to require examination, adjustment, servicing, or maintenance while energized.” For the given skid, the AHJ would need to make a determination if the equipment is likely to be serviced while energized. Since the skid most likely contains a motor, there is a good chance the equipment will be serviced while energized. Therefore, the requirements in 110.26(A) come into play. I hope this helps in providing clarification. — Lanny McMahill, CMP-1 (September/October 2006) | Return to top | Question 2. Does Section 110.26 of the NEC-2002 apply to disconnect in regards to working clearance? I have a 30-A, 480-V, 3-phase, non-fused disconnect mounted on a wall behind a row of pump motors. You can walk between the motors to access the disconnect but it does not have 30" wide or 42" to grounded parts in front. — C.B. Answer 2. First, the scenario presented has a minimum amount of information; therefore, to provide a reasonable response to the question, clarification of the code requirements and an assumption are in order. Generally, Article 110 contains requirements applicable to all electrical installations. Spaces about electrical equipment are an example of one such requirement. Section 110.26 requires that “sufficient access and working space shall be provided and maintained about all electric equipment . . . .” To clarify the objective of this requirement, the term to focus on is sufficient. According to the NEC Style Manual, the term sufficient is possibly unenforceable and vague. Consequently, interpretation of the term sufficient requires judgment by the authority having jurisdiction (AHJ). From a practical standpoint, sufficient generally implies enough to perform a task, such as operation and maintenance, without being excessive. Subsection 110.26(A) further requires that where such electrical equipment is “likely to require examination, adjustment, servicing, or maintenance while energized,” the working space must have a minimum depth, width and height. The term to focus on here is likely as it too is possibly unenforceable and vague. From a practical standpoint, the word “likely” generally implies having a high probability of occurring. Therefore, if a high probability exists that the electrical equipment requires examination, adjustment, servicing, or maintenance while energized, then the working space must have a minimum depth, width and height. For motor installations, the NEC requires one or more disconnecting means to disconnect the controller and motor. At least one disconnecting means must be located in sight from the controller location, the motor location, and the driven machinery location. Assuming the “30-A, 480-V, 3-phase, non-fused disconnect” is for the motor, is this disconnect likely to require examination, adjustment, servicing, or maintenance while energized? The answer is, yes. A high probability exists that over time the disconnecting means will need to be checked, inspected, or opened and closed while energized. Keep in mind, however, that this is a judgment call for the AHJ, and it may be determined that a high probability does not exist. If so, the minimum depth, width and height requirements do not apply. Regardless of such determination, keep in mind that sufficient working space must still be provided and maintained about the electrical equipment. Again, sufficient implies enough to perform a task without being excessive. — Lanny McMahill, CMP-1 (November/December 2006) | Return to top | Question 3. Is it correct for the electrical inspector to turn down a request to make a tap to the buss of existing switchgear? The AHJ has ruled that tapping onto an existing switchgear violates the original listing of the equipment and therefore will need to be re-listed or field certified by a NRTL. The expense of having to replace the equipment is way too expensive and also the other avenues have all been exhausted. The equipment has available buss bars that have holes in it already and the manufacturer of the equipment has indicated they are alright with this proposed method. The AHJ has indicated that although holes are available in the buss it was not designed or listed for conductors to be tapped here. His thought is that the location of the tap is not approved or allowed by the NEC and secondly that the testing criteria of the original listing is now jeopardized. Could you give some insight on this to see if the manufacturer of this 20-year-old equipment should or should not be able to allowed this scenario or if this should be tested and listed by a NRTL? — R.M. Answer 3. Thank you for your question; for clarification, the response is split in to five parts. First, the AHJ has responsibility for code enforcement, consistency, and for approving an installation or procedure. The electrical safety of any installation is of paramount importance. An AHJ does not want to be over or under restrictive when it comes to minimum Code requirements. Deciding on the acceptability of an installation or procedure must be thoroughly considered, and most AHJ prefer to error on the side of safety when enforcement of an installation practice or procedure is not clearly defined in the code. Generally, the definition of AHJ, Sections 90.4 and 110.2 provide the answer to the question. These sections address enforcement requirements and note that the AHJ is responsible for making interpretations of the code and for accepting equipment and materials. Although this may not be the response desired, the AHJ can turn down the request to make a tap. Second, let’s look at the switchgear tap. Switchgear generally implies metal-enclosed power equipment for over 600 volt installations, so for discussion purposes here the term switchboard is appropriate. In addition, the question does not indicate if the tap connection is on the line or load side of the switchboard, or if the switchboard is used as service equipment. Section 230.82 requires that tap connections on the supply side of a service disconnecting means must be provided with the service equipment. The conductors connected to such terminals are service-entrance conductors. The conductors on the load side are feeder conductors. Such conductors must be protected in accordance with 240.4. Section 240.4(E)(3) allows for tap conductors – see definition of tap. For load side connections, the code is not so clear, so the AHJ must make a determination on the suitability of the tap connection. Third, examine the tap conductors. Section 240.21(B) addresses several applications of feeder tap conductors. Assuming the application for the switchboard is a tap not over 3 m (10 ft) long, and the tap conductors leave the enclosure, the tap conductors must have an ampacity of at least 1/10 the rating of the overcurrent device protecting the switchboard. For example, a 3000 A switchboard would require the tap conductors to have an ampacity of at least 300 A. So, keep this in mind when sizing tap conductors. Fourth, the switchboard tap connection. This appears to be a minor task; however, it requires serious consideration by the installer and the AHJ! Generally, the holes in a switchboard’s load side busbars are not intended for tap connections. These holes are typically standardized in size and location and are likely intended for the manufacturer’s use in building the equipment. The holes allow for ease in mounting busbars to insulators, securing field connection terminals and making splice connections. If the holes are intended for tap connections, then the switchboard manufacturer should specify this in the installation instructions. Other considerations for a switchboard tap connection include: wire bending space, bracing and securing conductors, temperature rating, spacing from adjacent energized parts, and busbar loads. It should be noted that the switchboard busbar size and ampacity rating may not be per code. Switchboard manufacturers are permitted to perform equipment temperature testing which generally allows for the use of smaller busbars. Finally, the difficult decision! Although the manufacture may be all right with the proposed method, the tap connection as proposed likely violates the listing and labeling of the equipment. Such connection could easily jeopardize the entire installation too. Generally, the AHJ does not have the necessary tools, time, resources, information, and engineering data to evaluate a field modification to a switchboard. Therefore, a judgment call is necessary. In lieu of replacing the equipment, and to error on the side of safety, a field evaluation is a reasonable alternative; however, one may not be pleased with the outcome. As a note, perhaps the manufacturer can provide the AHJ with the instructions on how to do a tap connection without violating the listing and labeling of the equipment. Again, thank you for the question! — Lanny McMahill, CMP-1 (January/February 2007) | Return to top | Question 4. I am trying to determine whether the NEC or other supporting standards specifically require an uninterruptible power supply (UPS) that is to be used as a source of power for emergency systems, including both emergency lighting and power loads, to be listed to UL 924, Standard for Emergency Lighting and Power Equipment or to some other UL standard. Section 700.12(C) states that uninterruptible power supplies used to provide power for emergency systems shall comply with the applicable provisions of 700.12(A) and (B). The applicable provisions of 700.12(A) and (B) do not include any listing requirements. NFPA 101, Life Safety Code, 7.9.2.5 clearly covers unit equipment and battery systems for emergency luminaires. However, it does not address equipment used to power other than exit and entrance lighting. UL 1778 specifically excludes UPS units for use as emergency systems or legally required standby systems as described in the NEC. It would seem that due to this deliberate exclusion in UL 1778, that there would be a standard for UPS units for use as emergency systems or legally required standby systems. I am not able to find such a standard. I have checked UL’s online Certifications Directory and found numerous manufacturers that have UL 924 listed UPS offerings. I have not found anyone working with those manufacturers who can answer questions pertaining to the listing applicability for these units. The only listing requirements I have found pertain to the transfer switch as an integral part of an ECE as defined in NFPA 111, Stored Electrical Energy Emergency and Standby Power Systems. Chapter 6.2.3.1 states: “Each transfer switch shall be listed for emergency service as a completely factory-assembled and factory-tested apparatus unless under the conditions of 6.2.3.2.” Chapter 6.2.3.2 states, “Electronic or electromechanical switches that constitute an integral part of the ECE shall be permitted, provided they form part of a listed equipment.” This requirement does not specifically state to which standard the ECE is to comply. — M. D. Answer 4. The National Electrical Code, Article 700, Emergency Systems, does not specifically require that the emergency source of power, such as generator sets, uninterruptible power supplies, fuel cells, and so forth, must be listed to UL Standard 924, Emergency Lighting and Power Equipment. Section 700.3, however, requires that “All equipment shall be approved for use on emergency systems.” Approved is defined as “Acceptable to the authority having jurisdiction.” Therefore, the AHJ is responsible for approval of emergency systems equipment. Most AHJs do not have the time, tools, or expertise to evaluate electrical equipment for safety. Typically, the AHJ will rely on equipment listing and labeling. Listing and labeling provides reasonable assurance that the equipment complies with the appropriate product standard and is safe for installation and use. Uninterruptible power supplies are covered under UL Standard 1778, Uninterruptible Power Systems (UPS). As noted, UL Standard 1778 does not cover UPS units for use as emergency systems. Most likely, this is because UL Standard 1778 lacks the more restrictive requirements noted in UL Standard 924. Some UPS manufacturers may be submitting their equipment for a special listing and labeling to UL Standard 924. This may be the reason online certification directories indicate “numerous manufacturers that have UL 924 listed UPS offerings.” It should be noted too that UL Standard 924 does not include requirements for UPS equipment. Obviously, the performance of an emergency source of power is of critical importance for any emergency system. Keep in mind that in addition to equipment approvals, there are standards, such as NFPA 110, Standard for Emergency and Standby Power Systems, and NFPA 111, Standard for Stored Electrical Energy Emergency and Standby Power Systems that address installation issues, performance criteria and system requirements, too. These standards may provide the AHJ with the necessary information to determine the suitability of a UPS as an emergency source of power. Such standards can be used to supplement NEC requirements. To summarize, the NEC does not specifically require that a UPS used as an emergency source of power be listed to UL Standard 924. However, NEC 700.3 allows the AHJ to require such listing. Technically, the AHJ could require that all emergency systems equipment be listed to UL Standard 924; yet, that is likely not the intent of the NEC. — Lanny McMahill, CMP-1 (March/April 2007) | Return to top | Question 5. The city of Las Vegas inspectors are requiring the water district to have sprinkling systems installed in our electrical rooms (up to 5 kV gear, not outdoor rated) and above our cable trays (THHN). Is this OK per the NEC? — J. S. Answer 5. The National Electrical Code does not require sprinkler systems in buildings or structures. The sprinkler system is likely a requirement of the jurisdiction’s building and fire codes. The building and fire codes generally require sprinkler systems for specific building type occupancies, uses and locations. The NEC does not prohibit the installation of sprinkler systems in electrical rooms and above cable trays—this is regardless of voltage. General use electrical equipment (“not outdoor rated”) can be installed in these locations. Therefore, unless there is something specific in the local jurisdiction’s code requirements to prohibit the installation of sprinkler systems in the 5 kV electrical equipment rooms, then yes, this is “OK per the NEC.” As an aside, the use of sprinkler systems around electrical equipment is a frequent cause of debate. The potential for accidental operation, equipment damage due to water release, and the simple fact that electricity and water are not a good mix are a few concerns. Those concerns, however, are generally outweighed by the fact that automatic sprinkler systems have proven to be a primary component in the overall life and building safety system. Statistical fire data indicates that where sprinkler systems are installed in buildings and structures, the loss of life and property is substantially reduced. — Lanny McMahill, CMP-1 (March/April 2007) | Return to top | Question 6. What is the difference between the term listed and identified? — M. P. Answer 6. The terms Identified and Listed are defined in NEC-2005 NEC, Article 100 as: “Identified (as applied to equipment). Recognizable as suitable for the specific purpose, function, use, environment, application, and so forth, where described in a particular Code requirement.” “Listed. Equipment, materials, or services included in a list published by an organization that is acceptable to the authority having jurisdiction and concerned with evaluation of products or services, that maintains periodic inspection of production of listed equipment or materials or periodic evaluation of services, and whose listing states that either the equipment, material, or service meets appropriate designated standards or has been tested and found suitable for a specified purpose.” A fine print note (FPN) follows each definition to provide examples and clarification of the terms. For the term “identified,” the FPN mentions “investigation by a qualified testing laboratory (listing and labeling)” as an example of determining suitability of equipment for installation and use.  For example, equipment that is “identified for direct burial” or “identified as sunlight resistant” likely requires an evaluation by a qualified testing laboratory.  The listing and labeling provides reasonable assurance that the equipment is suitable for the intended application.  Such evaluation would be difficult or impossible to do in the field.  Typically where the term “Identified” is used in the NEC, listing and labeling comes into play.    For the term “listed,” the FPN clarifies that the method for “identifying listed equipment may vary for each organization concerned with product evaluation”.  This allows for some discretionary judgment by the authority having jurisdiction (AHJ) to determine what organizations are acceptable.  The FPN further clarifies that in addition to the equipment being included in a list published by a qualified testing laboratory, many AHJ require that the equipment must also be labeled (see NEC definition of “Labeled”). To summarize, the term “Identified” denotes that the equipment must be suitable for the installation or use as required by the code; the term “Listed” indicates that the equipment has been evaluated by a qualified testing laboratory and consequently published in a directory identifying such equipment.  For NEC purposes, “Identified” and “Listed” are separate and distinct terms.  However, so as not to be remiss, it is also fair to say that the terms have a commonality via labeling! — Lanny McMahill, CMP-1 (November/December 2007) | Return to top | Question 7. I’m a member and I have a question; will it be a code violation according to Article 80 to allow power on new construction that is in the rough in stage? I am not sure if I’m wording this right, but my AHJ wants to the allow power on buildings under construction without inspection, after the rough electrical has been approved, the only other inspection that will be made is the final inspection on these new constructed residential buildings. I think this is unsafe and should not be the full responsibly of the electrical contractor or JC. There is also the concern of GFCI requirements in chapter 5. — J.D. Answer 7. First, for clarification purposes, Article 80, Administration and Enforcement, was new to the 2002 National Electrical Code (NEC).  It was intended for informational purposes only and did not apply for code enforcement purposes unless specifically adopted by the local jurisdiction. Article 80 provides the authority having jurisdiction (AHJ) with the appropriate language and a means and method to administer and enforce the NEC where such provisions are not available.  Article 80 in the 2005 NEC was relocated as new Annex G, Administration (note: the requirements did not change).  Since Article 80 is informative unless specially adopted, it was appropriate to relocate it to the Annex in accordance with Section 90.3, Code Arrangement. Second, it may be impracticable for the NEC to address the “allow power” concern, as many variables come into play.  Obviously, where a building or structure is in the rough in stage, and energizing the electrical system and equipment could possibly create an unsafe condition (incipient or imminent), it would not be wise to allow power.  Yet, where the installation is code compliant and safe, and a general need exists to energize various parts of the building or structure, allowing power may be feasible.  For example, there may be a need to allow power and operation of the fire and security systems; elevators and fire pumps; heating, ventilating, and air conditioning equipment while the building or structure is in the rough in stage. The operation of these systems could be for building and life safety or construction purposes. Although the building or structure may be incomplete, key considerations to allow power is if the system or equipment to be energized is safe and code compliant — generally, such determination requires serious consideration via human intervention! Third, the NEC provides minimum installation requirements for “the practical safeguarding of persons and property from the hazards arising from the use of electricity.”  The NEC does not mandate how these minimum requirements are to be enforced.  The governing body, organization, individual, agency or AHJ responsible for enforcement makes such determination, so how the NEC is enforced is an administrative decision.  Nevertheless, all users of the NEC should have a responsibility and obligation to meet minimum code requirements! Lastly, NEC-2002 Article 527 (NEC-2005 Article 590) covers temporary electrical power and lighting installations. Permanent building or structure wiring methods, materials, and equipment necessary for the function or operation of the building or structure are not temporary power and lighting installations. Temporary power and lighting installations must be removed upon completion of its purpose, use, or allotted time.  Keep in mind that due to the nature of installation and use, ground-fault circuit interrupter (GFCI) protection requirements are generally more restrictive for temporary installations.  For permanent installations, the GFCI requirements must comply with other provisions in the NEC.  I hope that this provides some clarification to the concerns. — Lanny McMahill, CMP-1 (November/December 2007) | Return to top | The views of the authors of Focus on the Code and the editor are provided solely as a public service.  The views expressed are not the official position of NFPA, the NEC Correlating Committee or any of its panels, IAEI, IAEI News, or the author's employers. Nor are they intended to represent a formal or informal interpretation of the NEC.

Home  | Join | Advertising | Seminars | Contact Us | Privacy Statement | Legal Notices
Copyright © 1997-2008 IAEI. All Rights Reserved.