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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19
votes
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 ...
10
votes
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?
8
votes
4answers
2k views

Why are 120 V general receptacle circuits limited to 20 A?

The NFPA-70 (National Electrical Code) prohibits the use of breakers larger than 20 A for general receptacles. But I have my doubts. A 20 A breaker on a 120 V circuit with appropriately sized wires ...
8
votes
4answers
643 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 ...
7
votes
3answers
2k views

Any way to meet code with 40.7% or 40.44% conduit fill?

I’m running conduit along the walls in my shop (in a commercial warehouse) to provide power to some machines and additional outlets. The service is 3 phase, 208 V, 100 A. One of the machines requires ...
7
votes
1answer
40k views

Is there a length limit on grounding conductor to ground rod?

My service panel is over a concrete patio, it was improperly grounded in the crawlspace. I cannot drive a proper ground rod in the crawlspace so I would like to drive one into the earth on the side ...
6
votes
1answer
14k views

Installing a new 240v receptacle - what do I need to know?

Provided I use a box large enough to meet the fill requirements (and use 10 AWG conductors), are there any additional requirements I should be aware of when installing a new 240v 30 amp receptacle for ...
5
votes
2answers
5k views

How are equipment grounding conductors counted for determining conduit or junction box fill?

Suppose one is doing junction box fill calculations for a typical NM-B installation such as the one shown below for a switch box with one normal and one three-way switch. Which of the wires count ...
5
votes
2answers
189 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 ...
5
votes
1answer
141 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 ...
5
votes
2answers
258 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 ...
4
votes
2answers
2k views

Ok to conceal electrical junction box under cabinet behind removable toe-kick

There is a 5 or 6 inch gap between the floor and the bottom of my kitchen cabinets. I have ikea cabinets so the toe kick is connected to the cabinet legs by plastic clips. It comes off just by pulling ...
4
votes
1answer
849 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?
4
votes
1answer
14k views

How many ground rods are required for panel and subpanel?

I have a main service panel with two breakers: the main service breaker and a single large breaker to another subpanel in the same structure. All other circuits are serviced from the subpanel. My ...
4
votes
1answer
1k views

NEC, use more extension boxes or an access panel?

What is the maximum number of extension boxes you can hang from a ceiling? This is ridiculous and I probably need one or two more to meet the new drywall ceiling. Are junction boxes permitted behind ...
4
votes
1answer
583 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
votes
2answers
74 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
votes
1answer
13k views

Can Romex (NM-B) be run in conduit for more than 10 ft when starting from the breaker panel?

The answers to this question indicate that NM can be run in conduit: Can Romex (NM-B) be run through conduit? I was hoping to enclose 12-2 NM-B in EMT for about 20 feet from the breaker box up my ...
4
votes
2answers
8k views

What to do with the wires when removing baseboard heaters

I recently put in a forced-air whole house HVAC system in my old house. I'll be yanking the old electrical baseboard heaters from everywhere in the house soon. I'm wondering what all would be ...
4
votes
1answer
1k views

Conduit Underground - Ways for tunneling under obstructions?

I'm running into a situation where it's increasingly difficult to bury this PVC underground 18" in some spots due to massive tree roots. Changing directions and/or destroying the roots isn't an option....
4
votes
2answers
153 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 ...
4
votes
2answers
169 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 ...
3
votes
3answers
436 views

Does this violate electrical code? (UF run plugged into GFCI to use smart outlet)

I built a deck on the back of my house last year and installed a new breaker and a handful of outdoor electrical outlets. I wanted one outdoor outlet to be switchable via a smart outlet, but my smart ...
3
votes
2answers
865 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 ...
3
votes
2answers
823 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 ...
3
votes
1answer
3k views

When replacing non-grounding type receptacles is a GFCI receptacle required, or can any GFCI device be used?

Under the NEC (it was 210(7)(d)(3), but appears to have moved around some), it is permissible to replace an ungrounded receptacle with a GFCI receptacle, then wire further ungrounded or non-grounded (...
3
votes
2answers
431 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 ...
3
votes
2answers
749 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-...
3
votes
4answers
2k 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?) ...
3
votes
1answer
2k views

Does the circuit providing a light at the electrical panel have to be ONLY for that light?

Does the circuit providing a light at the electrical panel have to be ONLY for that light? I'm fairly sure there specifically has to be a light at the panel, as well as a circuit with an accessible ...
3
votes
1answer
149 views

Is it NEC-compliant to place a GFCI or AFCI receptacle or deadfront device in a location not readily reachable?

NEC 240.24 requires overcurrent devices (fuses/breakers, incl. AFCI/GFCI/DFCI breakers) to be placed so that their operating means is no more than 6'7" off the ground under most circumstances, and ...
3
votes
1answer
259 views

electrical work: create “future boxes” - is this to NEC code?

I would like to run cable for an in-wall heater but not actually connect to the heater right now, I just want to get the cable run and connected to the sub-panel (along with all the other cables that ...
3
votes
1answer
222 views

What are the rules for making your own conduit KOs in nonmetallic junction boxes?

Some North American electrical boxes (usually nonmetallic ones) lack conduit knockouts, as they are designed solely to clamp NM cable. Unfortunately, some devices (the RIB series of enclosed, UL ...
3
votes
1answer
1k views

How many circuits are recommended for this basement game room remodel?

Ok so this paint photo is roughly what I want to do to my basement. The lights are 6 inch recessed lights. The fireplace blower was on the old 15 amp circuit so I dont see a problem there. It ...
3
votes
1answer
119 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 ...
3
votes
1answer
366 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 ...
3
votes
2answers
111 views

Is rodent damage considered “physical damage” under the NEC?

Does the potential for rodents to access/gnaw on a cable under normal circumstances render it subject to "physical damage" in the sense the NEC intends that term to be used?
3
votes
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 ...
3
votes
1answer
2k views

Can service entrance and branch circuit cables be commingled in an auxiliary gutter?

One of the major Code defects in my current house that I want to rectify at some point is the fact that the (only) panelboard is mounted too high up on the wall (the current panelboard's service ...
3
votes
1answer
293 views

Listed electric baseboard heaters that permit installation below outlets

Are there UL-listed electric baseboard heaters that do permit being installed below outlets? The FPN in 210.52: Informational Note: Listed baseboard heaters include instructions that may not ...
3
votes
2answers
5k views

NEC Definition of “Maintained Spacing” for Wire in Free Air

This seems like a simple question, but I cannot seem to find the answer in the 2008 NEC. There are references to "maintaining spacing" in many sections of the code such as the following: 310.15.B....
2
votes
2answers
5k views

How do I properly place devices in an electrical enclosure?

I have to put together an electrical enclosure that includes, some terminal blocks, fuses, a power supply (110-24V,3.2A) all of which will be used to provide power for a series of sensors and ...
2
votes
2answers
1k 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 ...
2
votes
2answers
105 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 ...
2
votes
2answers
32k views

Is it okay to staple romex to a floor joist when running it perpendicular behind a finished basement ceiling?

Taking down my ceiling to run some wire to new outlets. The outlets are going in an area with an unfinished ceiling, so I know the romex there will need to be ran through the joists when going ...
2
votes
3answers
317 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 ...
2
votes
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 ...
2
votes
1answer
323 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 ...
2
votes
2answers
611 views

Is this type of ground wire connection NEC compliant?

Found this recently, done by a licensed electrical company in the state of California. Is this compliant? If not, is there anything that could be added to make it legal? (I see "ground clamps" for ...
2
votes
2answers
504 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....