Questions tagged [nec]

For questions about the National Electrical Code, NFPA 70. Just about all US jurisdictions that have adopted an electrical code use the NEC, often with a handful of local or state level amendments.

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1k views

OK to bundle wires together with colored electrical tape?

I have 3 bundles of 3 12AWG THHN wires each, black-white-green (red tape) black-white-green (blue tape) black-white-green (black tape) these 3 bundles come out of the load center and into 1/2 EMT. ...
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1answer
3k views

What is a 'Yoke' in NEC / electrician parlance?

NEC rules sometimes refer to "the yoke". For example: 1999 NEC § 210-4(b): Dwelling Units. In dwelling units, a multiwire branch circuit supplying more than one device or equipment on the same ...
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1answer
54 views

What NEC code limits circuit breaker selection?

I'm looking for a citation of the section of code that states more or less "You may only use breakers in a breaker panel that said panel lists as approved for use therein.". What is the section ...
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1answer
1k views

does the NEC allow conduit attached to my house to an outbuilding or does it have to be buried?

I have a shed im running electrical to, which is detached. the subpanel in the shed is being powered by a 40amp double pole from the main service with THHN/THWN 8 gauge wire. I am going to attach ...
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3answers
5k views

Is it OK to create a third prong ground from a cold water pipe, for a 2-wire circuit?

When or is it NEC code compliant to upgrade a 2-wire circuit, by adding a third prong equipment ground from a nearby cold water pipe? A different case of borrowing a ground from a nearby circuit is ...
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1answer
637 views

Splitting off one leg of a 20A 220v circuit for a plug - Is this to code?

I want to avoid buying another breaker and using a slot up in my sub panel just for one plug. I bought a plug\box kit which contains a 15A receptacle. I assume this wouldn't be to code since the ...
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4answers
124 views

Several Electrical Mains into a Single Panel [closed]

For an existing building, seven single-phase mains supplies with meter devices installed by the electrical company are supplying electricity into a same tenant installation. The tenant receives a ...
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2answers
2k views

Would it be reasonable and legal to use AFCI receptacles next to a panel instead of AFCI breakers?

I've been googling, searching this community and looking over the 2017 NEC codebook (which can be very confusing) and I've come to the conclusion that a crystal clear, no nonsense, straight forward ...
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1answer
67 views

How do I qualify for the 75C table in the ampacity chart?

Suppose we direct-buried some 8 AWG cable. It's now under a parking lot, and retrenching it is out of the question. Now, needs have changed and we need to get 50A out of the circuit, which is ...
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1answer
62 views

FMC run for GFCI receptacle?

I have a water heater room 5x8 that needs a GFCI receptacle added to the ceiling for a hot water recirculating pump. The heater is large and obviously hard plumbed in so cannot be moved and rigid ...
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2answers
103 views

Switchable 50A outlets for arc welder

I'm hoping to run two 240 V 50 A outlets for an ARC welder. One will be outside and the other inside the shop. If I install a double pole double throw switch such that only one receptacle can be ...
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1answer
4k views

NEC code requirements for exterior outlet

Are there any code requirements with regard to the position of an electrical receptacle on an exterior wall? Such as distance above the ground, distance from a corner, distance down from a roof ...
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1answer
662 views

Are there any NEC restrictions for wiring 220v and 110v sockets on the same dual pole breaker?

I am working on an electrical upgrade for my garage. Some equipment I have requires 20A 220V power. Other equipment only needs 15A or 20A 110V. I would like to run in from a single circuit protected ...
4
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1answer
912 views

Do NEC receptacle spacing rules apply to solid (half-wall) banisters

I have a solid banister over my stairs. If it counts as a wall per NEC, then it needs an outlet. I can't find the reference in NEC defining a wall. Anybody know if this counts?
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1answer
1k views

Use 60Amp disconnect as a pass-through to another disconnect

We would like to add a second air-conditioning unit. The original 60 Amp disconnect is grounded via EMT to the panel. The existing EMT will meet code requirements for both conduit fill and derating ...
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2answers
2k views

NEC code regarding grounding and conductor pass through

I am adding a mini split system to my house which currently has a smaller air-conditioning condenser in place. In brief, the house is very old so we opted for a ductless mini-split over trying to ...
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2answers
104 views

How should a GFCI be installed according to the NEC?

I am taking a National Electric Code safety class as part of an electrical maintenance certificate course. On one of my quizzes, it asks me to explain how a GFCI is to be installed and tested. I've ...
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1answer
798 views

Is there any way to do an Ufer (concrete-encased) ground with a monolithic slab that has a vapor barrier?

If I understand correctly, when using a monolithic slab (where the footers and slab are poured as one piece), the vapor barrier is installed under the slab and the footers. The NEC does not consider ...
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2answers
112 views

How is the minimum conductor size (of some type) for a certain run determined?

I have a 200A service in a garage. I would like to run cable from this to a 100A service in a house. I would also like to run from this to a separate 50A service in the house which will supply ...
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1answer
139 views

BX cable in plaster by sink

I am re-plastering a wall in my kitchen after removing some damaged plaster. I am burying the electrical in BX cabling before plastering as allowed by NEC. However, NEC does say BX is not allowed in ...
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1answer
310 views

Does the lighting fixture size change the number of allowed wires in a junction box?

In am working on a 1920s era home. The electrical system in the house has been updated several times in a very hodge-podge way. Originally the house had conduit in the attic going from light ...
2
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1answer
310 views

Does the NEC permit brazing for connections to ground electrodes?

I need to connect several copper-clad ground rods together with AWG 6 solid copper wire for lightning protection, and as part of the electrical service grounding. I also need to connect some 2.5" ...
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1answer
260 views

How can we move a subpanel without replacing the supply cable?

We recently installed a subpanel, installed it ourselves and had it inspected. Now, as part of the ongoing renovation of the house, we have decided we need to move the panel over 22 inches. The 6 awg ...
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3answers
349 views

Properly installing a grounded subpanel for lightning protection

I'm installing a large antenna on the side of my house opposite the electrical service entrance. The antenna must be grounded, by nature of its design. For lightning protection, it's important that ...
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2answers
633 views

Is a divided wireway or auxiliary gutter considered one wireway/gutter or two for derate purposes?

A common accessory with auxiliary gutters or wireways is a divider that extends the length of the gutter/wireway and creates two wiring compartments instead of one. This is more commonly used to ...
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1answer
109 views

Code compliance of running EMT on exterior of exposed chimney inside

I am working on a 1920s era home with an exposed brick chimney inside. The chimney is not connected to a fireplace but is used to vent the water heater and furnace in the basement. I am currently ...
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2answers
280 views

Can multiple panelboard interior/cabinet combos or loadcenters be chained together to form a single “logical panelboard”?

Background Both the houses I deal with (which are quite far apart btw) are in need of panelboard reworks: One still has the original fusebox, never mind that the main disconnect is basically at the ...
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2answers
135 views

Can a UL 1953 listed power distribution block be deployed in a panelboard cabinet?

So, one of the things I want to do if I ever get a chance to have a house wired to my specifications is have each room have its own lighting homerun to the panel, but multiplex these homeruns onto a ...
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1answer
146 views

Can an electrical subpanel be directly mounted to a hvac supply plenum?

Can an electrical sub panel be directly mounted to an HVAC supply plenum. I usually see and have installed the disconnect or sub panel to the actual equipment on a wall near by or used some sort of ...
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1answer
379 views

Single Neutral for Several Smart Switches

I have some (seemingly common, but specifically unanswered) concerns about providing a neutral wire to smart switches that are in a single multi-gang box (4-6 switches on different circuits). I am ...
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1answer
7k views

Do I need AFCI protection on new lighting circuits or just for outlets?

I am in the process of re-wiring a 100 year old house. I want to make sure everything is done to the new NEC codes. I need to know if arc fault protection is required on lighting circuits or just ...
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5answers
114 views

Flexible cabling for wiring

Article 400.12 forbids the usage of flexible cords for fixed wiring, but what makes an NM-B cable made out of stranded 14ga THHN non-flexible? EDIT: Terms 'cord' and 'cable' are used interchangeably ...
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3answers
4k views

What does “No Other Outlets” mean for a kitchen 20A branch circuit?

I'm trying to wire my kitchen up to code, which means (based on the outlet spacing rules) I need 6 counter-top outlets. How many branch circuits do I need? When the NEC talks about the 2 "appliance" ...
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1answer
250 views

How do I power fluorescent lights hanging from a drop ceiling?

Our basement has a high ceiling, and somebody fancied it up with a drop ceiling. The lighting is the common 4' 2-lamp fluorescent shop lights that are cord-and-plug connected, and hung from the ...
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2answers
793 views

Possible wiring configurations for isolated dishwasher location (satisfying 2014 NEC)

The key wiring requirements in the 2014 NEC seem to assume dishwasher placement in a cabinet space adjacent to the kitchen sink. For example, the placement of the GFCI receptacle, for use with a cord-...
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2answers
79 views

Does always-on safety lighting need a switch or other requirement?

With such low-power LED lights available, I've been setting up some of my lighting to simply be on all the time, 24x7, e.g. 1 of 6 downlights or 1 out of 4 LED "tube"s in a troffer. Usually I just ...
4
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2answers
170 views

Is it legal to torque-seal terminal screws on electrical equipment?

Torque seal is a lacquer-like product used in critical applications after a screw is tightened to provide a visual indication if the screw comes loose. Considering that a terminal screw on an ...
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2answers
105 views

NEC 2016 AFCI question

I am currently dealing with a little confusion regarding arc fault protection and how it would be enforced by 2016 NEC code. I'm not a licensed electrician, I'm doing an apprenticeship and the guy ...
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1answer
107 views

How can one make a connection where flexibility is necessary despite the connection being exposed to physical damage?

It seems that it is common practice in HVAC-land to use a LFNC whip to connect air conditioner condensing units to the house wiring. However, as statueuphemism rightly points out, it is eminently ...
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1answer
390 views

Is it okay to use an LFNC whip to connect air conditioner where subject to physical damage?

I have seen many air conditioners at ground-level in multiple cities near me that are connected using liquid-tight non-flexible conduit (LFNC) whips. Example: http://www.southwire.com/products/whip-...
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4answers
2k views

Over-the-range Microwave on small-appliance branch circuit

Either there is conflicting information or a lack of when it comes to this question. Is it allowed in NEC code to permit an over-the-range microwave to run off of one of the small-appliance branch ...
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1answer
535 views

Can a washing machine closet be located adjacent to an electric panel?

We want to relocate a washer/dryer into a closet that shares a wall with the house's electrical panel (which is in the kitchen). Any code violations here or considerations?
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2answers
267 views

Does replacing an electrical junction box require the wiring to be brought up to code?

I live in Sparks, Nevada and the 2011 National Electrical Code applies to me. I am installing a new bathroom fan on a separate circuit from the existing bathroom circuit. I want to change the ...
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4answers
3k views

Is it legal to add a jumper wire to a conductor that is too short in a junction box?

I live in Sparks, Nevada, and the 2011 National Electrical Code applies to me. My work will be inspected when complete. I am replacing a switch and have found that someone before me (accidentally?) ...
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1answer
314 views

What are the requirements for supporting non-metallic cable through a finished wall?

I know this basic question has been answered before by reference to 334.30(B), but there's an aspect I don't understand. Does 334.30(B) allow unsupported installation if 334.30(b)(1) OR 334.30(b)(2) ...
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1answer
105 views

Can a single set of conductors feed utilization equipment *and* a subpanel simultaneously under the NEC?

So, let us assume we have a set of conductors (hot/neutral/ground) going off to some piece of utilization equipment. Can I also run a set of conductors of appropriate ampacity off this circuit to a ...
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1answer
342 views

If a breaker is GFCI/AFCI protected, does the NEC still require garage and exterior outlets to be GFCI protected?

I am looking into upgrading the cabling from very old clothed 14-3 wire to 14-3 MC wire and the outlets in my garage and I understand they must be GFCI protected; however, can I simply replace the ...
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1answer
79 views

Hooking up additional outlets & lights to a central vac circuit?

My unfinished basement has a central vac on its own 20A circuit. The central vac is plugged into a 15A duplex outlet (not hardwired). I want to finish my basement and build a closet around the vac ...
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1answer
4k views

Do both legs in 220V have to be switched?

I posted this question but for some reason I can't get back into my account: Is it up to code to do a parallel circut with 220V? Is there a limit to number of splices? Most things I see with 220V ...
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2answers
533 views

Is it up to code to do a parallel circut with 220V? Is there a limit to number of splices?

State is Florida. I am wiring a continuous run non-submersible irrigation well pump. I am using a 30A breaker with #10 THHN in Sch 40 PVC conduit buried 18". I could have gone direct bury but I ...