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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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Running a low-voltage audio cable through a wall; with or without conduit?

I'm running wire for a 70V audio system and there is a barrier wall in the way of my run. I was wondering if it is legal as far as NFPA 70 / NEC goes if I just poke a hole in the wall (non-insulated ...
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0answers
23 views

Support EMT between two closely adjacent junction boxes?

EMT must be supported within 3 ft of termination ends. I have two junction boxes 3 ft apart. Do these junction boxes support each other? Does this count as support?
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1answer
100 views

Derating 6 current-carrying conductors?

I'm having a hard time understanding 310.15(B)(2)(a). Here's the boat I'm in: I hooking up a tankless water heater that calls for 3 40 amp breakers (it's a 24 kw Ecosmart). So I put in a sub panel in ...
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3answers
74 views

Is “14 AWG” NM-B allowed by the newest NEC for new residential construction?

Is "14 AWG" NM-B allowed by the newest NEC for new residential construction? My concern is what the NEC says concerning 14 AWG NM-B for new residential construction. I have been told that the "NEC ...
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2answers
177 views

Can I wire a doorbell transformer in-wall this way?

My current under-powered doorbell transformer is in a very awkward location (old home, etc.) and in a location where several old wires are cable-nutted together and I would rather not replace it there....
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1answer
98 views

What does NEC require for strapping down conduit and wire here?

Below is a picture of the current conduit and wire setup for my new underground service into my house with generator automatic transfer switch and manual transfer switch to allow me to switch to an ...
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1answer
40 views

Do I need to upgrade other circuits if I only plan to change one?

(San Francisco, California) I plan to run a new dedicated circuit for a kitchen appliance, and to get up to code also move the bathroom to its dedicated circuit as well. This is an old house. The ...
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1answer
30 views

can an indoor Transfer Switch be used on the other side of the wall as an outdoor service entrance and main panel?

Can an indoor Transfer Switch be used on the other side of the wall as an outdoor service entrance and main panel? The concept is: The outdoor service entrance is wired through the wall to the SE ...
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1answer
50 views

Electrical outlet clearance from a hot water panel radiator

What is the clearance of an electrical outlet from a hot water panel radiator? So facing the wall with a window and having a panel radiator down below hanged/fixed on the wall, how far away left and ...
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1answer
51 views

Homeowners Electric Permit - Mongomery County, Maryland, USA [closed]

Our county allows homeowners to test to acquire permits for "rough wiring" and "heavy-ups" (https://www.montgomerycountymd.gov/DPS/Process/combuild/homeowner-electrical.html). I did electronics/...
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2answers
750 views

Can I run #14 armored cable behind baseboards?

Residential basement remodel problem: Replacing old, ungrounded wiring. Problem is cinder block walls. Inside, the exterior walls have rigid insulation and one layer of 1 x 3 furring strips ...
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2answers
65 views

NEC (United States)

Is there a website where I can access the complete and most recently updated version of the United States NEC for free?
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2answers
118 views

Can I add USB outlets to bath/hall lighting circuit box (not GFCI)?

My bathroom, inside near door, has a 2-gang box, containing 2 light switches, powering combination ceiling light and fan. This box is fed by hallway lighting circuit, and the work box is not covered ...
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2answers
331 views

Main Breaker Panel or Main Lug Panel for Sub-panel in Attached-Detached Garage

I am installing a ~100-amp sub-panel in my "attached-detached" garage (an "attached-detached" garage is a detached garage that shares a continuous roof with the home). The sub-panel will be fed by my ...
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1answer
40 views

Intersystem grounding bus ran out of terminals; now what?

My intersystem grounding terminal bus is out of available terminals, and I have two additional communication wires to ground to it. Does NEC allow supplementary bus bars? NEC 250.94 seems to imply no, ...
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2answers
70 views

Operational Electrical Panel in an unfinished building — safe? Sane? Legal?

Is it realistic to have an operational and functioning load center panel (with power supplied only to temporary outlets mounted near the panel), fed by an offgrid solar system, in a half-built ...
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2answers
818 views

Is it OK to have a light that can only be controlled via automation?

I am retrofitting the main light in a room to be controlled by a home automation system, in this case, I'm using z-wave, but for purposes of this question, it could be any digital protocol. I would ...
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0answers
30 views

Approved weatherproof way of connecting SER into panel

I have a knockout in an outdoor electrical panel that is above the uninsulated portion of the panel. I need to run 4/0 SER wire into the panel. According to NEC 312.2, I need a wet listed fitting when ...
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2answers
71 views

THHN to NM-B wiring, Transition from External Piping Conduit to in wall junction box

I am working on a project, In my own home, Permanently installing a Faux Fireplace, Shiplap, and some iron pipe shelves. The shelves are going to have built in lighting in the form of Edision Bulbs at ...
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1answer
5k views

Is this wiring safe and is it according to code?

A single 12-3 cable was run to a double switch to control individual lights. The white is used as a hot, is this wiring correct/per NEC code?
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1answer
57 views

2 meters for 1 structure

We are currently building an addition to our house. It was a duplex before (one part stick built, other part mobile home, they were connected by a common entryway). We moved the mobile home away and ...
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1answer
57 views

Can a single cable type do the following

Running from a new 200amp main interior in the attached garage, out a 150 amp breaker into 4/0 cable (4/0-4/0-4/0-2/0 assumed). The cable will travel about 30 feet inside through raceways and EMT (...
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1answer
80 views

are tamper resistant receptacles required when rewiring an old house

rewiring an old house due to having knob and tube wiring. it it code to have all receptacles tamper resistant? Does the NEC require hard wired smoke and carbon monoxide detectors? Are "in-use" ...
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1answer
46 views

is AFCI required for 220v CA residential?

As I understand it CA now requires AFCI protection for practically all residential outlets. I'm setting up my theater room and it calls for a 50A 220V NEMA 6-50 outlet for the subwoofer I want but I'...
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2answers
340 views

Relabeling 6-AWG Wire

I'm pulling 2 hots, 1 neutral and 1 ground through conduit to a subpanel and I was wondering if it's possible to use the same color wire and just relabel the endings. I was thinking of using 6 AWG ...
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1answer
155 views

PVC conduit into PVC box: Can I make it watertight when using a threaded fitting? Are sealing locknuts allowed?

I have some 2" PVC conduit coming out of the ground and into a PVC box where it enters with a terminal adapter and held in place with a locknut. I intended to use a sealing locknut to keep the box ...
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1answer
172 views

is there an outlet box mounted overcurrent protection device?

I am adding some additional outlets and outside lights to my garage. The existing outlets are on 12 gauge wiring, so presumably a 20 amp circuit (I did not check this - did not have my reading ...
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3answers
2k views

Can I add a non-GFCI receptacle in the garage for a freezer?

It seems that GFCI-protected receptacles are required in all areas of the garage (even on the ceiling, where the garage door opener plugs in). Can I install a non-protected (15A) receptacle ...
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4answers
541 views

How should ground wires be handled when updating switch loops in an older home?

I have a house built in the 1950’s with fabric covered NMC wiring still present in most circuits. Those original wires are all 12/2 with no ground. I am currently in the process of replacing some of ...
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1answer
139 views

Questions regarding my plan for new 50A circuit (with pictures)

Overview Pictures/diagrams at the end. I will pull permits and would like to do this correctly. I will be disconnecting an unused 40A circuit and replacing it with a new 50A circuit to my garage for ...
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2answers
302 views

Is NEC code for non-metallic cable applicable now that I've installed an attic ladder?

Just installed an attic ladder. I've read this: What is the proper 'per code' method for running nonmetallic sheathed cable above a ceiling in the attic? So my attic is now "accessible" and ...
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3answers
7k views

How to connect grounding wire to gas pipe for 2017 NEC 250.104(B)

I'm trying to interpret and apply the 2017 NEC bonding requirements from 250.104(B) to my existing home gas line. I've read this related question to determine I should use #6 AWG wire, but I'm unsure ...
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3answers
303 views

Is a Garage considered a 'Dwelling' for standalone electric service?

I just wrapped up adding new overhead 100 amp service for my parent's garage outside Chicago. My Mom is a retired ceramics teacher and wanted a 30A two phase kiln and/or welder in there and the ...
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2answers
140 views

Move grounds to subpanel when I moved 8 single pole breakers to same subpanel?

When I move 8 breakers from main panel to a subpanel (a few feet away) can I simply move the hot and neutral only to subpanel? The 8 breakers are grounded in the main panel already. A 100 amp breaker ...
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2answers
179 views

Can I use a ground rod as an equipment ground for a detached garage?

I'm in a bit of a dilemma. The house we bought has a detached garage supplied by 12/3 UF with ground. The previous owner/handyman set this up as a multiwire branch circuit (MWBC) with a twist: one ...
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1answer
677 views

interpretation of conduit vs raceway wet location vs outdoor vs NM NM-B

eventual question: for a sealed PVC conduit external to house, does that qualify as a wet or damp location preventing use of non metallic (NM or NM-B) indoor type wire? And does underground feeder (...
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2answers
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
2k 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
53 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
826 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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1answer
4k 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
463 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
113 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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0answers
36 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
56 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
95 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
3k 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
520 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
809 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?