Question 1. Is there NEC code that prohibits shared neutrals in lighting and duplex branch circuits? This is one of the most dangerous things for electricians working on 277-volt lighting circuits. "No shared neutrals" was a standard in the facility I was working in. Please let me know if this is covered somewhere the NEC code. — T.V. a Answer 1. The Code defines a Multiwire Branch Circuit as follows: "A branch circuit that consists of two or more ungrounded conductors that have a voltage between them, and a grounded conductor that has equal voltage between it and each ungrounded conductor of the circuit and that is connected to the neutral or grounded conductor of the system." This appears to be what you have described as branch circuits with a shared neutral. Multiwire branch circuits are permitted by Section 210.4 and can be used in dwelling units and other than dwelling occupancies. There are conditions that have to be followed when using multiwire branch circuits. Section 210.4(C) permits only line-to-neutral loads to be supplied. Exceptions permit multiwire branch circuits to supply only one utilization equipment and when the ungrounded conductors are opened simultaneously by the branch-circuit overcurrent device. Section 210.4(B) requires that the ungrounded conductors of a multiwire branch circuit in dwelling units be simultaneously disconnected when the multiwire branch circuit supplies more than one device on the same yoke. Section 210.7(C) requires simultaneous disconnection of the ungrounded circuit conductors of branch circuits when "more than one branch circuit supplies more than one receptacle on the same yoke." These branch circuits may or may not be multiwire branch circuits. Also Section 300.13(B) does not permit a device connection, such as lampholders or receptacles to provide continuity when the grounded conductor would be interrupted upon removal of the device. In other words, the neutral has to be "pigtailed" when multiwire branch circuits are used. There may be instances where multiwire branch circuits should not be used. The Fine Print Note (FPN) of 210.4 warns that a "shared neutral" or multiwire branch circuit may not be advisable when nonlinear loads such as computer loads are encountered. Two-wire branch circuits would be better than multiwire branch circuits where harmonic currents are present. Electricity is dangerous whether you use a two-wire or multiwire branch circuit, 120-volt or 277-volt and the electrical wiring should only be serviced by a qualified person. — James W. Carpenter, CMP-2 | Return to top | Question 2. I am an electrical contractor, and one of my incorporated areas has an inspector who says the laundry room must have a separate circuit for just the washer, and that if we install another outlet in the room for a convenience outlet, it must be on another circuit. My interpretation of 210.11 (C)(2) [NEC 2002] is that all the outlets in the laundry room should be on the same circuit. If I am not correct, would the second (and any additional outlets) have to be on a 20- or 15-amp circuit, and would the washer outlet have to be a single outlet? If I am correct, what can I use to convince the inspector? B.T. Answer 2. Section 210.52(F) refers to laundry areas rather than a laundry room. Section 210.11(C)(2) states that the laundry branch circuit is allowed to supply outlet(s). “At least one additional 20-ampere branch circuit shall be provided to supply the laundry receptacle outlet(s) required by 210.52(F)...” This section allows an additional outlet to be installed for laundry equipment in the laundry area (for example, a plug receptacle to be used for an iron or additional laundry equipment located within the laundry area). The inspector’s interpretation that another outlet installed in the laundry area for a convenience outlet would be correct if the use is not for associated laundry equipment. The interpretation by the authority having jurisdiction (inspector) would determine the use of additional outlet(s) from the laundry branch circuit. The laundry area/laundry room can be supplied by additional branch circuits/outlets of either 15- or 20-ampere circuits for general use. However, the laundry receptacle outlet(s) is required by 210.11(C)(2) to be a 20-ampere branch circuit. —Ernie Broome, CMP-2   | Return to top | Answer 3. At least one light outlet containing a switch, or controlled by a wall switch, shall be installed where these spaces are used for storage or contain equipment which requires servicing. Your first question was “Is a pull-chain light fixture (luminaire) allowed?”  The answer is yes, at least one lighting outlet containing a switch or controlled by a wall switch shall be installed at the usual point of entry to these spaces. Your second question refers to the pull-chain light fixture (luminaire) and where it can be located. It must be located at the point of entry. The location must be immediately located (occurring at once) as soon as you enter the space. The distance of six or eight feet that you refer to would not be immediately located (occurring at once) as soon as you enter the space and would not be acceptable according to 210.70(A)(3) of the NEC 2002. Note that the switch is on the pull-chain light fixture. The string is not the switch. —Ernest S. Broome, CMP-2. | Return to top | Question 4. Retired as an electrician from Canada, I am looking for some information on the use of split-circuit duplex receptacles in U.S. kitchens over the last three decades. These multiple-circuit receptacles have been mandatory in our Canadian kitchens (countertops) since 1966 and I was wondering just how extensively they have been used in the U.S., and whether they have ever been part of the National Electrical Code. I do know that the U.S. now uses 20-amp receptacles in their kitchens, but I am wondering if in the past the split receptacles were used extensively. I would appreciate any help you can give me in this area or steer me to someone or some organization that might be able to help. — B. F. Answer 4. I will try to give you the information I have in regards to split-wired receptacles. In the National Electrical Code 2002, Section 210.4 for Multiwire Branch Circuits permits these to be used in dwelling units with certain restrictions for safety measures. These restrictions are as follows: you must use a means of disconnecting simultaneously all ungrounded conductors; you must make sure that each circuit is being fed from the same panelboard where the branch circuits originated; and you must use a suitable handle tie across the two breakers or a double pole breaker to disconnect the two circuits that feeds the split-wired receptacle or equipment. These rules must be followed anytime two ungrounded conductors of a multiwire branch circuit are terminated on a receptacle of the same yoke. I can only speak in our jurisdiction that this practice of split -wiring receptacles is hardly ever used in kitchens or for equipment.This is a design issue that is totally up to the electrical contractor or builder. I can tell you that over the last 30 years of wiring and inspecting dwellings, I may have seen it used only a few times.The requirement of split-wired receptacles has never been a mandatory rule in the NEC. — Ernie Broome, CMP-2 | Return to top | Question 5. Is an  area that has a 24" x 80" doorway and is L-shaped with approximately 33 square foot and a height of 4', under a stairway landing, considered to be a storage area that would require a switch and a light? — B.B. Answer 5. Review 210.70(A)(3) [NEC 2002], Storage or Equipment Spaces. For attics, underfloor spaces, utility rooms, and basements, at least one lighting outlet containing a switch or controlled by a wall switch shall be installed where these spaces are used for storage or contain equipment requiring servicing. At least one point of control shall be at the usual point of entry to these spaces. The lighting outlet shall be provided at or near the equipment requiring servicing. As you have indicated in your question, the space is used for storage and is an underfloor space and thus should have a lighting outlet installed. — Raymond W. Weber, CMP-2 | Return to top | Question 6. Do a dishwasher and a garbage disposal have to be on separate circuits? Can you have any lighting outlets on with these? — E.F. Answer 6. Reference 110.3(b) [NEC 2002], Installation and Use. "Listed or labeled equipment shall be installed and used in accordance with any instructions included in the listing or labeling." Thus, if the manufacturer specifies a separate dedicated circuit for a dishwasher or garbage disposal, then the response is yes.If a separate circuit is not indicated, then we must review Section 210.19(A)(1), General. "Branch-circuit conductors shall have an ampacity not less than the maximum load to be served. Where a branch circuit supplies continuous loads or any combination of continuous and noncontinuous loads, the minimum branch-circuit conductor size, before the application of any adjustment or correction factors, shall have an allowable ampacity" equal to or greater "than the noncontinuous load plus 125 percent of the continuous load." I would not consider a dishwasher or garbage disposal to be a continuous load. Next, we need to consider Section 210.23(A) 15- and 20-Ampere Branch Circuits. "A 15- or 20-ampere branch circuit shall be permitted to supply lighting units or other utilization equipment, or a combination of both, and shall comply with 210.23(A)(1) and (A)(2)." Subsection (A)(1) states, "The rating of any one cord-and- plug-connected utilization equipment shall not exceed 80 percent of the branch-circuit ampere rating." Subsection (A)(2) states, "The total rating of utilization equipment fastened in place, other than luminaires (lighting fixtures), shall not exceed 50 percent of the branch-circuit ampere rating where lighting units, cord-and-plug-connected utilization equipment not fastened in place, or both, are also supplied." The final answer is that it can be done if proper circuit ampacity is provided for and the system branch circuit is designed as indicated. — Raymond W. Weber, CMP-2 | Return to top | Question 7. Is a 28-amp electric clothes dryer plugged in to a 30-amp individual branch circuit in compliance with the permissible loads of NEC 210.23, or does the 80 percent rule apply? — E.K. Answer 7. Section 210.23 [NEC 2002] states, "In no case shall the load exceed the branch-circuit ampere rating. An individual branch circuit shall be permitted to supply any load for which it is rated. A branch circuit supplying two or more outlets or receptacles shall supply only the loads specified according to its size as specified in 210.23(A) through (D) and as summarized in 210.24 and Table 210.24." Section 210.23(B) states, "30-Ampere Branch Circuits. A 30-ampere branch circuit shall be permitted to supply fixed lighting units with heavy-duty lampholders in other than a dwelling unit(s) or utilization equipment in any occupancy. A rating of any one cord-and-plug-connected utilization equipment shall not exceed 80 percent of the branch-circuit ampere rating." Thus, the question asks if a 28-ampere load is acceptable on a 30-amp individual branch circuit, and the answer is yes, as long as that is the only utilization equipment on that circuit with one outlet or receptacle. The 80 percent rule applies when two or more outlets or receptacles are installed per 210.23(A) through (D). — Raymond W. Weber | Return to top | Question 8. I've recently had an experience with the local inspector regarding arc-fault circuit-interrupter (AFCI) breakers. He tells me that I cannot put a ground-fault circuit-interrupter receptacle on a circuit protected by an AFCI breaker, unless it happens to be on the end of the branch circuit. He quotes Section 210.12(B). My code makes no mention of this, by any stretch. I dealt with this issue years ago when arc faults were referenced in the last Code. This raised a question in my mind back then so I contacted the manufacturer. They said there were no problems with such an application. Can anybody give me any guidance or offer any advice. — J.R. Answer 8. As much as I hate to say it, the inspector is wrong (hurts me deeply). There is nothing in Section 210.12(B) [NEC 2002] that makes a GFCI receptacle installed at any point on that AFCI-protected branch circuit for outlets installed in dwelling unit bedrooms a code violation. As fast as the electrical industry and products are changing, we all need to attend update training and seminars to stay current with the Code requirements. — Raymond W. Weber | Return to top | Question 9. I am in the process of preparing to adopt the 2002 NEC. I have run across one Code change that appears to be causing other jurisdictions some concern that I will outline below. Section 210.12 now requires all branch circuits that supply 125-volt, single-phase, 15- and 20-ampere outlets to be arc-fault protected. Typically, the smoke detectors are served by a branch circuit installed solely for that purpose. Although they serve an outlet in the bedroom, was the change intended to require smoke detectors to be arc-fault protected? — B.C. Answer 9. As stated in Section 210.12(B), "all branch circuits that supply 125-volt, single- phase, 15- and 20-ampere outlets installed in dwelling unit bedrooms shall be protected by an arc-fault circuit interrupter listed to provide protection of the entire branch circuit." First, we must go to the definition of outlet in Article 100, which is: "A point on the wiring system at which current is taken to supply utilization equipment." The smoke detector is an outlet by definition and is installed in the bedroom. Panel 2 in its deliberations of the 2005 NEC ROP and ROC had a number of code change proposals and subsequent comments to exempt the smoke detectors from the requirement. As was discussed at the code panel meetings, even though that smoke detector has a battery back-up system and may not be easily accessible, it would still need AFCI protection. Comments about nuisance tripping of the breaker have not been widely experienced in the field. The panel even had a proposal to exempt an outlet in the bedroom area that was for the use of health care related diagnostic equipment, that was supported in the ROP phase and then deleted in the ROC phase because of the standard for the equipment manufacturers to have a leakage current level well below the plateau of the AFCI functioning. This is a safety feature that is, in my opinion, by far the best deterrent next to GFCI for protecting homes and families from potential fire-related losses.—Raymond W. Weber, CMP-2 Technical Editor’s Note: The mention of smoke detectors in this reply is intended to reference single station smoke alarms connected to the branch circuit. Smoke detectors that are part of a fire alarm system are covered by rules in Article 760. Revisions in 760.21 and 760.41 exempt power sources for fire alarm circuits from being supplied through AFCIs. The circuits addressed in the question are branch circuits as defined in Article 100 not fire alarm circuits or power source circuits for fire alarm circuits. See the scope of Article 760 and the definition of fire alarm circuit for additional information. | Return to top | Question 10. I would like to know what the intent of the Code was concerning outdoor receptacle location. Is an outlet required to be accessible to a person that is standing on the ground? Does a receptacle on the deck or porch that can’t be reached from the ground/grade fulfill the Code requirements? — G. D. Answer 10. The answer to the first question the answer is yes, and the answer to the second question the answer is no. The Code reference is 210.52(E), Outdoor Outlets [2002 NEC]. For a one-family dwelling, and each unit of a two-family dwelling that is at grade level, at least one receptacle outlet accessible at grade level and not more the 2.0 m (6 1/2 ft.) abovegrade shall be installed at the front and back of the dwelling. See 210.8(A)(3) which addresses the GFCI protection requirement. The term accessible is used and by definition when applied to equipment and not wiring methods states, "Admitting close approach; not guarded by locked doors, elevation, or other effective means." Notice the term elevation is used and in the Code the panel has indicated at grade level and not more than 2.0 m (6 1/2 ft) abovegrade. No minimum dimension was set or given, but it should be reachable by standing on or at grade and not exceeding the designated height. Oftentimes railings are treated as if they were solid walls, and cannot be reached through to get at a required receptacle location and therefore do not meet the Code intent. Remember the requirement in Section 406.8(B)(1) for outdoor receptacles to have the (bubble) or in use cover and not just a standard weatherproof cover that does not enclose the attachment plug when it is inserted. It should be noted that this is my opinion and not an official position of NFPA or CMP-2. — Raymond W. Weber, CMP-2 | Return to top | Question 11. Would it meet the intent of Section 210.12 to exclude AFCI protection for a 120-volt circuit feeding the smoke detector outlets in dwelling unit bedrooms? — E. D. Answer 11. According to both the 2002 and the 2005 NEC directives, the answer would be no, it would not. All outlets in the bedroom are to have AFCI protection; the smoke alarm in the bedroom area meets the definition of an outlet and therefore requires the AFCI protection. At the code panel meeting, this issue was debated and proposals and comments were submitted to CMP-2 for exempting the smoke alarm outlet in the bedroom, but none received the majority vote by the panel to make an exemption to the AFCI requirement. — Raymond W. Weber, CMP-2 | Return to top | Question 12. In the 1999 NEC, under the section for the requirements for kitchen island outlets, the Code says that only one outlet is needed for a space 12" x 24". It then goes on to say that island counter space divided by a sink, stove or refrigerator is considered separate counter spaces. Assuming that the outlet is allowed to be mounted below the counter, on a 4' x 6' island with a small vegetable sink 24" in from the end, does the Code allow only one outlet to be installed 4' away and on the opposite corner where it would have been allowed if there were no sink? What if there was also a stove, does this now create three 12" x 24" spaces, or does the stove/sink have to divide the island counter top completely? — K. K. Answer 12. Sections 210-52(C)(2) and (4) [1999 NEC] address your question. The answer would be that yes, two would be required; with one being installed on either side of the sink/stove top unit. You may wish to refer to the 2005 NEC, 210.52(C)(2) and (4) and Figure 210.52 for information that may apply in your jurisdiction in the future. Under that concept and given certain dimensions, you may have a requirement for receptacles behind sinks/stove units located adjacent to wall areas but not on the island areas. — Raymond W. Weber, CMP-2 | Return to top | Question 13. How are cord-and-plug connected window air conditioner loads handled in sizing services? Should they be considered as fixed in place equipment (like a central air conditioner)? Are they part of the 3-watt-per-square-foot lighting load (like any other cord-and-plug-connected appliance)? I’m upgrading an existing multi-tenant apartment house to provide additional circuits and 120-volt receptacles for the ten-ant’s window air conditioners and I am unclear how to approach the load calculations for the building. — G. O. Answer 13. The load is definitely not part of the 3-watt-per-square-foot lighting load, even though it is cord-and- plug-connected. Under certain conditions, it may even be a continuous load for long durations of time. I would identify the units to be utilized with its load requirements and consider them as fixed equipment. Thus ensuring that a worst-case scenario can be handled via sufficient electrical system capacity. I would use 220.4(A) [NEC-2002] as a guide. — Raymond Weber, CMP-2 | Return to top | — See more CMP-2 questions — 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.

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