20 Amp Circuits

[wwhitney]

Where the switch supplies a single lighting outlet, I think you can make a case for using fixture wire as a tap to the lighting outlet, with the tap originating at the load side of the switch.

Just curious--what code section would require that the switch be in the branch circuit wiring, rather than the fixture wire?

But for the OP, the insulation types in Table 402.3 Fixture Wire do not overlap with the insulation types in Table 310.4 on branch circuit wiring. So if the OP has #14 building wire, rather than fixture wire, 240.5(B)(2) would not apply.

Cheers, Wayne

 

[don_resqcapt19]

Just curious--what code section would require that the switch be in the branch circuit wiring, rather than the fixture wire?

But for the OP, the insulation types in Table 402.3 Fixture Wire do not overlap with the insulation types in Table 310.4 on branch circuit wiring. So if the OP has #14 building wire, rather than fixture wire, 240.5(B)(2) would not apply.

Cheers, Wayne

Maybe nothing..I just see the supply to the switch as part of the branch circuit.
Yes, standard building wire is not fixture wire so not permitted by this rule. Same reason some get into trouble making their own fixture whips using building wire and not fixture wire.

 

[charlie b]

Couldn't that result in leakage current with properly sized wire too?

Good question. My answer is "yes." But a properly sized breaker would prevent the wire from being damaged, whatever the amount of current.

 

[CoolWill]

Maybe nothing..I just see the supply to the switch as part of the branch circuit.
Yes, standard building wire is not fixture wire so not permitted by this rule. Same reason some get into trouble making their own fixture whips using building wire and not fixture wire.

And this is why I have contempt for code absolutists who have no problem with a #18 fixture wire on a 20 amp circuit but quibble if you made your own #14 fixture whip. Because "the code says so".

 

[electrofelon]

. Same reason some get into trouble making their own fixture whips using building wire and not fixture wire.

Any idea why the code has this distinction between building wire and fixture wire? Is there any reason this should be in the code?

 

[don_resqcapt19]

Any idea why the code has this distinction between building wire and fixture wire? Is there any reason this should be in the code?

No idea.

 

[Little Bill]

I don't know why it was allowed, but in this area, years ago, it was common for #14 to go from a switch to a light when the circuit to the switch was #12.

 

[Jraef]

Penny pinching installers. What other code sections did they cut corners on?

The NEC is definitely overly conservative when it comes to protecting small conductors, but it says what it says and, to my knowledge, this had never been allowed.

It's never been allowed to my knowledge too. BUT, it was "common practice" when I was an apprentice in 1975 working for a contractor building cheap tract homes in a predominantly low-income town. I didn't question anything at the time, but later after going into industrial, it bugged me once I got my J-man license and was more well versed in Code lore. So I dug into it with Code references I had access to in the 80s, going back to I think 1964 or 65. That was not allowed back then, common or not. Now, were inspectors just being lazy and not checking, or did they deliberately "look the other way" when they came across it, based on that "can't do harm" aspect? I have no idea.

 

[kwired]

We are only allowed to do that only in limited applications like tap conductors.

And motors is one the next biggest applications where overload protection isn't necessarily at the beginning of a circuit, and short circuit protection at the beginning of the circuit is allowed to be higher than for most general use circuits