NEIS: Code Question of the Day

NEIS: Code Question for Tue, 10 Nov 09

Tue, 10 Nov 09 00:00:00

Subject: Ring cutting Conductors I am a Building Inspector and I have an electrician doing a CIP job for our city who insists that it is ok to ring or cut wires in an oversized conductor to be able to make the connection to the breaker. I say no and that he should use the tap rule to get to right size. I have never seen anything in the NEC that allows for cutting the wire and I would appreciate your input, Keith Weiner Supervising Building Inspector City of San Leandro

NEIS: Code Question for Mon, 9 Nov 09

Subject: Cord and Plug Connection One of our customers has a projector installed below a suspended ceiling; permanent install with mounting hardware above. It is supported by 1 1/2 inch pipe sleeve. It is powered by a ceiling mounted flush outlet above the projector. The customer wants to relocate the outlet to above the ceiling, run the projector cord through the mounting sleeve and plug it in above the ceiling so the cord will not be showing. Article 400.8 indicates this cannot be done. I have checked with two local city inspectors; one says it cannot be relocated to above the ceiling as it would be a Code violation; one says any appliance can be run into the ceiling area and plugged into an outlet above as long as it has a bushing or sleeve to run through because appliance cords are not permanently installed wiring methods. Which way to go?

Answer:

Let the Code decide. NEC 400.8- Uses not permitted: (1) As a substitute for the fixed wiring of a building (2) Where run through holes in suspended ceilings (5) Where located above suspended ceilings (6) Where installed in raceways Suggestion – Hardwire the projector to the outlet box.

Section: 400.8
Source: Charlie Trout

NECA is in the process of creating and revising several NEIS (ANSI approved standards), and would like you to participate in this process! Below is a listing of all standards in the process of being published or revised, if you feel that you would like to be involved in the review process, please contact Aidan McCallion at 301-215-4549 or by email at Aidan.McCallion@necanet.org . NEIS Revision Comment period ending on, Monday, November 9, 2009: NECA 200-200x, Standard for Installing and Maintaining Temporary Power at Construction Sites Comment period ending on, Monday, November 23, 2009: NECA 408-201x, Standard for Installing and Maintaining Busways NECA 409-201x, Standard for Installing and Maintaining Dry-Type Transformers Comment period ending on, Monday, November 16, 2009: NECA/FOA 301-200x, Standard for Installing and Testing Fiber Optic Cables Comment period ending on, Monday, November 30, 2009: NECA 331-200x, Standard for Building and Service Entrance Grounding and Bonding NECA 90-200x, Recommended Practice for Commissioning Building Electrical Systems Comment period ending on, Monday, December 7, 2009: NECA 407-201x, Standard for Installing and Maintaining Panelboards New NEIS in development: Comment period ending on, Monday, November 16, 2009: NECA NECA/BICSI 607-20xx, Standard for Telecommunications Bonding and Grounding Planning and Installation Methods for Commercial Buildings Comment period ending on, Monday, November 23, 2009: NECA 700-20xx, Standard for Installing Overcurrent Protection to Achieve Selective Coordination Comment period ending on, Monday, December 7, 2009: NECA 169-20xx, Standard for Installing and Maintaining Arc-Fault Circuit Interrupters (AFCIs) and Ground-Fault Circuit Interrupters (GFCIs) Comment period ending on, Monday, December 21, 2009: NECA 130-20xx, Standard for Installing and Maintaining Wiring Devices

ANSWERS: Answers are the author's opinions and do not represent formal interpretations of the National Electrical Code.

All answers are based on the latest edition of the NEC, unless the question requests a response based on a specific edition.

CONTACT US: To submit a question, subscribe to Code Question of the Day, or remove yourself from this list, please send an e-mail to codequestion@necanet.org.

ABOUT THE AUTHOR: Charlie Trout is a nationally-known NEC expert and author. He served on three different National Electrical Code-Making Panels and is past chairman of CMP-12. He is also a member of the NECA Codes & Standards Committee. In 2006 Charlie Trout won the prestigious Coggeshall Award, given to recognize outstanding contributions to the electrical contracting industry in the technical and training area.

NECA STANDARDS & SAFETY PRODUCTS: NECA publishes the National Electrical Installation Standards (NEIS), a series of ANSI-approved performance and quality standards for electrical construction. Visit www.neca-neis.org for more information. NEIS can be purchased in three formats: as paper books, on CD, or as .PDF downloads.

NECA also publishes safety books and CDs for the electrical industry. Visit www.necanet.org/store to purchase NECA safety products.

NEIS: Code Question for Mon, 9 Nov 09

Mon, 9 Nov 09 00:00:00

NEIS: Code Question for Fri, 6 Nov 09

Subject: 230.6 Clarification Hello Charlie When is concrete encasement of service laterals required when inside a building? This code seems a bit confusing as 230.6 says it needs to be encased if not under 2 inches of concrete or covered with 18 inches of earth, then it says if it is in a raceway per 230.43 it does not need encasement. We find this problem when entering a building from beneath into a crawlspace, underground parking garages, etc. It seems like a lot of the inspectors we ask don't fully have the answer. Please, offer your insight? Thanks Lance

Answer:

Hey Lance, The service disconnecting means must be located at a readily available point nearest the point of entrance of the service conductors (230.70(A)(1). The reasoning for this requirement is to limit the length of unprotected service-entrance conductors within the building. By unprotected I mean no overcurrent protection from short circuit or ground-fault. Service-entrance conductors, which are the conductors from the point of attachment to the building to the line side of the service disconnecting means are protected only by the utility transformer overcurrent protection. This protection is usually quite high and does not provide proper protection for the service-entrance conductors The service-entrance conductors are required to have protection from overload (230.90) which is provided by the overcurrent device in the main service disconnect. Your question relates to when the conductors are considered as being within a building. This can be better answered by determining when conductors are considered as being outside the building in accordance with (230.6). Conductors beneath a building are considered outside of a building where installed under not less than 2 in. of concrete or where installed in conduit and under not less than 18 in. of earth. Where installed within a building in a raceway that is encased in concrete or brick not less than 2 in. thick. Conductors that are considered as being outside a building (230.6): Beneath a building under not less than 2 in. of concrete or Beneath a building where installed in conduit and under not less than 18 in. of earth Within a building in a raceway encased in concrete or brick not less than 2 in. thick

Section: 230.6
Source: Charlie Trout

NEIS: Code Question for Fri, 6 Nov 09

Fri, 6 Nov 09 00:00:00

NEIS: Code Question for Thu, 5 Nov 09

This came up for conversation today: Can one conduit have both the 480 volt wires (primary wiring to transformer )and the 208 volt wires (secondary wiring from transformer )?The situation is this: there is a junction box around 20' away from the transformer. The customer wants to ‘save on using more conduits and junction boxes'. So, he wants to use one conduit from this j-box to the transformer (carrying both primary and secondary wires). The primary wires do have over current protection. Peter Klein- Service Manager Borrell Electric Co. Inc.

Answer:

Hey Peter, Thanks for your interesting question. Yes, In general both sets of conductors are permitted to be contained in one properly sized conduit. However, if I am reading this question correctly you have a 3-wire, 480-volt primary and a 4-wire, 208-volt secondary which is seven conductors to be installed in one conduit. This brings in Table 310.15(B)(2)(a) which requires derating of conductors and in your installation the conductors must be derated to 70%.

Section: Table 310.145(B)(2)(a)
Source: Charlie Trout

NEIS: Code Question for Thu, 5 Nov 09

Thu, 5 Nov 09 00:00:00

NEIS: Code Question for Wed, 4 Nov 09

Subject: Sharing Neutral Hello Charlie, I am a new reader, thanks for the great job that you do. I was talking to a fellow electrical contractor and he was saying that there is no more sharing of neutral in the 2008 edition of the NEC based on his conversation with a electrical inspector that he spoke with. Neither he nor myself can find it in the code. Can you direct us to where it might be? Thanks again. Rohan in NJ

Answer:

Hey Rohan in NJ, Welcome to CQD and thanks for contributing. There is nothing in the Code that prohibits sharing a neutral. There are however new requirements in 210.4(B) & (D) that require simultaneous disconnection of all ungrounded conductors of a multi-wire circuit and grouping of conductors in panelboards that may tend to discourage the use of multi-wire circuits where the neutral is shared.

Section: 210.4
Source: Charlie Trout

NEIS: Code Question for Wed, 4 Nov 09

Wed, 4 Nov 09 00:00:00

NEIS: Code Question for Tue, 3 Nov 09

Subject: CQD - October 21, 2009 Charlie, Please read the language in 406.11 and then 210.52. It says tamper resistant receptacles are required in all areas specified in 210.52. What area of a dwelling is not specified in 210.52? If a receptacle is installed in a dwelling tamper resistant construction is required. Your answer implies that if I install switched receptacles tamper resistance is not required? All the introduction to 210.52 says is these receptacles (if installed) are not counted for the required receptacles in the following paragraphs. It does not say tamper resistance is not required. Joe

Answer:

Hi Joe, Thanks for commenting. NEC 210.52 says that the receptacles required by 210.52 shall be in addition to any receptacle or area that is shown in 210.52 (1), (2), (3) and (4). This means that any receptacles installed in areas shown in 210.52(1), (2), (3), and (4) are in addition to the areas specified in 210.52 and are not counted as required receptacles. The areas designated in 210.52(1),(2), (3), and (4) are not specified as areas in 210.52 requiring receptacles and the language in 406.11 does not require tamper-resistant receptacles to be installed in these non-specified areas. Yes, as the Code is written, a receptacle controlled by a wall switch in accordance with 210.70(A)(1) Exception No. 1 does not require a tamper-resistant receptacle. There is a big difference between satisfying 210.70(A)(1) for a required lighting outlet and switching a convenience outlet for convenience. This whole thing could have been satisfied by saying, “all of the areas specified in 210.52 as requiring the installation of a receptacle outlet shall have tamper-resistant receptacles installed.”

Section: 210.52, 406.11
Source: Charlie Trout

NEIS: Code Question for Tue, 3 Nov 09

Tue, 3 Nov 09 00:00:00

NEIS: Code Question for Mon, 2 Nov 09

Subject: Response to CQD 13 October Good Day Charlie, I was just reading today's CQD and I must admit I really don't understand the writer's rational. He's seems to imply that the code should incorporate all the various “street” names and definitions used by electricians throughout the country when referring to devices, wire, cable, clamps etc… As an electrician with 37 years of experience it is the writer who should be assisting the younger electricians in the use of the correct terms and definitions as defined by the code. The code should take precedent after all it has been in existence longer than any current practicing electrician, including the writer. Our industry requires standards for a number of reasons, primarily SAFETY. He lists his title as Project Manager; as a Project Manager he should be well aware that specifications and other project documentation can be use in court as legal documents. This is another reason why there is a need for standards and not for slang or street terms. How many volumes of the NEC would need to be printed just to include slang and street terms? Would the NEC be required to print different term and definition books for all the various parts of the country and then more for other countries that have adopted the NEC? Regards, Jim Jackson, MIET, MIEEE Consulting Engineer

Answer:

Hey Jim, Thanks for commenting. I took the liberty of substituting some material in your comment. Yes, I really feel that we should all be on the same page. I have received numerous comments on this and they all appear to agree on proper referencing to all materials and equipment designated by the Code.

Source: Charlie Trout

NECA is in the process of revising an ANSI approved Standards (NECA 200-20xx, Standard for Installing and Maintaining Temporary Power at Construction Sites ). If you would like to comment and review the aforementioned standard, please e-mail Aidan and ask to be involved with this part of the process. The comment period closes on Monday, November 9, 2009 . NECA is in the process of creating a new standard (NECA/BICSI 607-20xx, Standard for Telecommunications Bonding and Grounding Planning and Installation Methods for Commercial Buildings ). If you would like to comment on this standard, please e-mail Aidan and ask to be involved with this part of the process. The comment period closes on Monday, November 16, 2009 . NECA is in the process of creating a new standard (NECA 700-20xx, Standard for Installing Overcurrent Protection to Achieve Selective Coordination ). If you would like to comment on this standard, please e-mail Aidan and ask to be involved with this part of the process. The comment period closes on Monday, November 23, 2009 NECA is in the process of revising an ANSI approved Standard (NECA 301-200x ,Standard for Installing and Testing Fiber Optic Cables ). If you would like to comment and review the aforementioned standard, please e-mail Aidan and ask to be involved with this part of the process. The comment period closes on Monday, November 16, 2009 . NECA is in the process of revising an ANSI approved Standard (NECA 331-200x, Standard for Building and Service Entrance Grounding and Bonding ). If you would like to comment and review the aforementioned standard, please e-mail Aidan and ask to be involved with this part of the process. The comment period closes on Monday, November 30, 2009 .