wire protection

[tom sanor]

I found a electrican running a #12 romex from a panel to a switch box and a #14 romex to the light box. I told him the n.e.c. would not allow that, I then tried to find it, I could not. Could someone please tell me where in the n.e.c. it,s located ? Thanks.

 

[Dennis Alwon]

I found a electrican running a #12 romex from a panel to a switch box and a #14 romex to the light box. I told him the n.e.c. would not allow that, I then tried to find it, I could not. Could someone please tell me where in the n.e.c. it,s located ? Thanks. tomsanor@hotmail.com

It is allowed as long as the breaker is a 15 amp one. Art. 240.4(D) will break it down

 

[Dennis Alwon]

I think the question is more like where does it say you can run a 14 gauge wire and put it on a 20 amp breaker. It does not. He is thinking of 240.5(B)(2) for fixture wires. These are branch circuit wires not fixture wires.

 

[augie47]

Although the Code does not prohibit it, I have know some inspectors who don't allow it...there may even be some local jurisdictions that have rules against it.
As Dennis notes, in most cases, by Code you would need a 15 amp over-current device. The "fear" is that someone would change the 15 amp OCP to a 20 not knowing the #14 was in the circuit. In an attempt to prevent this I have seen requirements to identify the circuit in some manner but doing so is not NEC required.

 

[infinity]

As Dennis stated Article 240 would govern the use of the #14 as part of the branch circuit and limit it to 15 amps. You could feed the switch with #8 conductor and feed the light with #14 and still be code compliant if the OCPD were 15 amps. There are other rules for fixture wires and fixture taps but as mentioned those would not apply to this branch circuit wiring.