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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4
votes
2answers
127 views

What are the legalities associated with mounting splicing wire connectors?

There are some situations, such as those involving large junction or pull boxes that serve as central takeoff points for many-plexed homeruns or homerun banks, enclosures that form central splice ...
2
votes
2answers
76 views

Correct gauge and jacket type for feeder wire to subpanel?

I need to install a 200A panel about 100 feet from the meter base. I have 400A service coming to the building, broken out at the meter base into two 200A exterior disconnects. One disconnect is ...
1
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1answer
97 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 ...
2
votes
2answers
148 views

Does it violate US wiring code to have non-standard outlets?

Note: this is entirely theoretical. I have no (current) plans to actually do this. Would I violate any state/national building/electrical codes if I installed BS 1363 (UK plug/socket) sockets on a ...
13
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2answers
2k views

What range of heights are allowed for wall receptacles?

I need to mount a receptacle on a basement wall. If I can mount it high enough, it can go on the wood cripple wall instead of having to drill into the concrete and risk the excellent watertightness ...
2
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2answers
83 views

Why does NEC require circuit breaker locks only on hard-wired appliance circuits?

The National Electric Code (NEC) Section 422.30 requires "permanently connected appliances" to have "lockable" disconnects, so that power can be reliably cut to the appliance when it is serviced. ...
4
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2answers
675 views

Handybox Extension

Can you stack a handybox with an extension outside of the drywall? This puts the total box size at just shy for 4". I know handyboxes can be used with conduit, but can they be double-stacked in a ...
2
votes
2answers
653 views

How to wire up a 240 V oven?

I recently purchased a Whirlpool WOS51ES4ES electric oven from Home Depot with the intention of installing it myself. Our old oven is gas, so I need to run a new 240 circuit. The oven draws 20A. I ...
0
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1answer
47 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 ...
0
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3answers
67 views

Electrical Question for Receptacles in guest house

Wiring a out door shed that has everything that a home does; bathroom kitchen living room and extra bedroom. Pretty much like a guest home you can say. When I run my wire in the bathroom of it. The ...
3
votes
2answers
397 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 ...
5
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3answers
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 ...
1
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2answers
56 views

Solar 240 VAC source and load wires sharing a conduit

I'm planning on installing a new electric oven and solar panels on my house soon. Given the location of everything relative to my electrical service panel, both the panels and the oven will need to ...
2
votes
2answers
82 views

Exterior to Interior Wiring and Code Deficiencies?

I recently installed a 100a exterior subpanel adjacent to my main panel to allow for the installation of 240V and 120V service to a shed on the opposite side of my house, along with a 240V dryer of ...
0
votes
3answers
102 views

How to run 10/2 THHN outdoor wire in finished basement along ceiling?

I need a 220v (intermittent load will be 14 A max) single phase outlet about 30 feet from my distribution panel in my finished basement. The distribution panel is outside on the first floor. I do not ...
19
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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 ...
1
vote
1answer
71 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 ...
4
votes
1answer
194 views

Can I paint a load center cover?

I would like to paint the cover and door of my flush mount load center to match the wall color more closely. The manufacturer does offer a white in addition to the standard grey cover, but it is hard ...
1
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0answers
60 views

1 generator + multiple ATSes: how can I install this to Code without unobtanium?

I want to supply standby power to both units in a separately metered duplex from a single permanently installed generator. The cheapest way to do this is a pair of bog-standard ATSes and a smallish ...
-1
votes
1answer
53 views

In conduit with 75C wire, can I use #14 wire for 20A circuits?

I note that with 8 AWG wire... in NM-B (Romex) cable I can only get 40A: I am required to pull from the 60 degree C column of Table 310.15(B)(16). However, in conduit, with 75C wire (THHN) and ...
2
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0answers
48 views

How do I connect surface wireway to a breaker box?

I am running Legrand/Wiremold 4000 series for a garage shop. The instructions for the panel connector (4086A) consist of a tiny picture that implies all I need to do is cut a large square hole in my ...
7
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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 ...
3
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3answers
611 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 ...
1
vote
1answer
143 views

Oven wiring - needing to add a ground, can I retrofit?

I'm dealing with a 1970-built home and the oven has 6-3 without ground running to the oven. 2 hots and the neutral. Got a new oven coming in and want to make sure it's wired right. I could run new ...
8
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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 ...
1
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2answers
94 views

IBT and whole house transfer switch

The inter-system bonding termination (IBT) is where other services like telephone and cable TV get their ground bonds from the house's grounding electrode system (ground rods). 2014 NEC (NJ) 250.94 ...
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0answers
42 views

Dedicated 240v 30A Circuit Switched for A/C and NEMA 14-30 [duplicate]

I have a dedicated 240 volt circuit that's hard wired into my air conditioning unit. The circuit has a 30 amp breaker at the main box and another 30 amp breaker on the wall next to my air conditioner....
1
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1answer
41 views

Stacking 'Main lug' load centers for garage

I am aware of most NEC codes and am actually asking if this is allowed, There really shouldn't be any reason..I also fully understand keeping my netural and ground seperate and how the bus bars are ...
3
votes
1answer
233 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 ...
1
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2answers
140 views

Why don't we just use combination AFCI/GFCI breakers for every circuit in a home?

With pretty much every circuit in a home needing one of the two types of protection (AFCI or GFCI), why don't all new homes have combination breakers installed just to be safe? Would it hurt anything ...
1
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3answers
86 views

Extremely low suspended ceilings? (NEC)

Here are the key points: Condo in NYC with concrete ceilings Recessed lighting "Exactly" The ceiling is to be dropped by only 2-1/2" The light in mind is a 1-1/4 LED light (Extremely low profile) Ex: ...
1
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2answers
95 views

Romex exiting junction box just below 8 feet

I am installing new outlets by drilling up from the garage between the wall cavity and fishing romex up. As seen in the picture: I had my first inspection and the inspector called out that the ...
0
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2answers
516 views

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 ...
3
votes
1answer
341 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 ...
0
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3answers
138 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 ...
0
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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 ...
2
votes
2answers
2k 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....
1
vote
1answer
479 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 ...
1
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1answer
42 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 ...
0
votes
1answer
124 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 ...
1
vote
3answers
5k 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" ...
7
votes
1answer
44k 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 ...
1
vote
1answer
88 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/...
3
votes
2answers
1k 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 ...
4
votes
2answers
316 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 ...
8
votes
4answers
953 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 ...
0
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2answers
66 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?
1
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2answers
2k 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 ...
1
vote
1answer
53 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, ...
1
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2answers
75 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 ...