circuit for floresent lights

[Timboe]

We are installing a circuit for some floresent lights in a wharehouse. The 12ga wire is run in conduit with a 20 amp breaker and at every light there will be a j box to wire into. The other guy is trying to tell me he wants to use 14ga mc from the j box to the light and tie it to the 12ga and the breaker won't have to be changed to a 15amp breaker because the whip is under 6feet from connection point to light. He claims its in the NEC allowing this. I don't know why he wants a 14ga wire here but I'm not thinking this is in the Nec. Is it or not

 

[Little Bill]

Not!
Either change the breaker to 15A or use 12 AWG the whole run.

 

[GoldDigger]

Not!
Either change the breaker to 15A or use 12 AWG the whole run.

Would it make a difference to use fixture wire for the whip?

 

[ActionDave]

We are installing a circuit for some floresent lights in a wharehouse. The 12ga wire is run in conduit with a 20 amp breaker and at every light there will be a j box to wire into. The other guy is trying to tell me he wants to use 14ga mc from the j box to the light and tie it to the 12ga and the breaker won't have to be changed to a 15amp breaker because the whip is under 6feet from connection point to light. He claims its in the NEC allowing this. I don't know why he wants a 14ga wire here but I'm not thinking this is in the Nec. Is it or not

I think what the other guy wants to do would be allowed under the tap rules if you were to use flexible conduit and THHN instead of MC.

If the lights had factory installed whips they would have 16AWG conductors, would already have connectors and would be legal without any fuss. I would get the whips.

 

[JFletcher]

I think what the other guy wants to do would be allowed under the tap rules if you were to use flexible conduit and THHN instead of MC.

If the lights had factory installed whips they would have 16AWG conductors, would already have connectors and would be legal without any fuss. I would get the whips.

Why is there an exception for lights? What code section is that under?

Also, do whips have to be made from stranded wire?

 

[iwire]

See 240.4 or 240.5 I think

The conductors have to be fixture wires listed in article 402.

That will mean TFFN not THHN

 

[Ponchik]

IMO the fixture wire must have the "F" designation, starts at the fixture and ends at the junction box where the circuit wires are. The wiring between the switch and the fixture is considered circuit wire not fixture wire.

 

[kwired]

The luminaires in question are likely limited to 20 amps maximum branch circuit, but there can be cases where the fixture taps can be on up to 50 amp branch circuits. Was more common when HID luminaires were dominant.

 

[ActionDave]

Why is there an exception for lights? What code section is that under?

I dunno. I'm not near a code book right now. There is some crazy stuff about lights in there though. Check iwire's code reference, he's been known to be right on occasion.

Also, do whips have to be made from stranded wire?

Not sure. I think that rule has something to do with lights hanging from chains.

 

[kwired]

Don't know for certain on the stranded issue, but have seen both solid and stranded in listed whips, probably more stranded then solid for that matter.

 

[ActionDave]

I have only seen solid wire in fixture whips.

 

[jumper]

I have only seen solid wire in fixture whips.

Ditto, assuming you are speaking of the ones that come with fluorescent troffers.

 

[JFletcher]

thx for the replies. yes, stranded wire with lights hanging from jackchains. will check the book when I get home

 

[dema]

If the warehouse is very large, and you are under an energy code, then you must compute voltage drop. The NEC recommends it, but most energy codes require it. That means that if you have a run of 200' with 12 amps on it at 120V, then #10 wire is required. Just FYI.