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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 2014 & 2017" codes do not allow it for new residential construction. Am just trying to find out for sure.

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    Probably yes on 15A circuits, unless your AHJ has something to say about it. Where are you located? – Aloysius Defenestrate Mar 31 at 17:11
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There is nothing in the NEC that forbids 15A circuits with 14AWG wire in new work

There is nothing in the NEC (2014 or 2017) that forbids the use of 15A circuits wired with 14AWG NM-B for general lighting and receptacles (irrespective of occupancy). Some localities do amend the Code to require the use of 20A branch circuits (with 12AWG wire, of course) for general lighting and receptacles in some or all occupancies, though, and there are also electricians who do not install 15A branch circuits, preferring to stick to 20A as a point of practice, but neither of these reflect on what the NEC actually says.

  • I'd like to see 15a circuits relegated to lights/fans, smokes, doorbell only. If monkeys with mastercards can just plug whatever they want into it, it should be a 20A circuit on 12AWG – Billy C. Mar 31 at 21:42
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There are two separate questions there.

Is NM-B cable allowed in your work?

Maybe, maybe not. NEC article 334 describes where NM cable can be used. This Stack's bailiwick is home residential, and it's usually allowed there, but watch out for local amendments; e.g. It is not permitted in Chicago.

Is 14 AWG wire allowed in your work?

NEC 240.4(D) indicates where 14 AWG wire is allowed, i.e. On 15A circuits only.

Again, watch out for local amendments; some places outlaw 15A circuits entirely and want 12AWG to be the smallest wire you use.

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Depends on what code in your area has to say, and what purpose you want to use it for, and what load and circuit breaker it will be for. For example: To connect a sub-panel, stove or dryer? Absolutely not allowed.

In the general case, in North America, the answer is yes. In fact, by far, the vast majority of wiring in North American homes is 14AWG NMB (also often known by the trade name "Romex"). It's generally used for all the 15A lighting and receptacle circuits throughout the house. In most cases, all of the rest of the rest of the house also uses NMB (just larger than 14AWG).

  • And the 12 AWG yellow is used for the 20A circuits throughout the house. – manassehkatz Mar 31 at 18:01
  • My concern is what the NEC says concerning 14 awg NM-B for new residential construction. I have been told that the "NEC 2014 & 2017" codes do not allow it for new residential construction. Am just trying to find out for sure. – samsly Mar 31 at 18:13

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