tap rules in bathrooms.

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jjflash

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the main question is can you down size to 14 wag wire in a bathroom for the lighting switch legs if the bathroom is a dedicated 20 amp circuit and every power jumper to the switch box is in 12awg? table 210.24 under 20 amp and tap says 14.
 
You're talking about branch circuit wiring not tap conductors therefore you cannot use #14 on a 20 amp circuit.
 
There are two concepts at play here, and you are only looking at one of them. Yes, the wire has to have sufficient ampacity for the load. Yes, a #14 will have sufficient ampacity for the load you are describing. But separate from this consideration, the overcurrent device must provide adequate protection for the wires connected to it. There is a special rule for small conductors, and it appears in 240.4(D). For your installation, you cannot attempt to protect a #14 wire with a 20 amp overcurrent device.
 
Charlie, I want to agree with you as I do not believe what the OP wants to do is code compliant.

But I do not think 240.4(D) applies here, if it did we could never use things like fixture wire etc.

I believe Mike Holt has said 210.19 prohibits it but I can't recall for sure.
 
jjflash said:
the main question is can you down size to 14 wag wire in a bathroom for the lighting switch legs if the bathroom is a dedicated 20 amp circuit and every power jumper to the switch box is in 12awg? table 210.24 under 20 amp and tap says 14.
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You could run a #14 tap from the 20A circuit to an individual luminaire, per 210.19(A)(4) Ex 1(b). However, you would only be able to extend the tap conductors 18" beyond the luminaire, so the switch would have to be mounted very close.
 
Fixture wire is covered by 240.5(B)(2) and that section permits fixture wire to be tapped from a branch circuit

240.4(D) would cover the OP's installation and prohibit #14 Copper conductors from being protected by a 20 amp overcurrent device.

Chris
 
david luchini said:
You could run a #14 tap from the 20A circuit to an individual luminaire, per 210.19(A)(4) Ex 1(b). However, you would only be able to extend the tap conductors 18" beyond the luminaire, so the switch would have to be mounted very close.
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Aren't standard fixture whips 6' long?
 
they whole point is its sufficient to run 1 light and you can't add anything off of the bathroom itself. the load is very very small. next i will be told i can't down size my wire for motors. i learned this way from the dallas chief inspector. a good while back but looking in all of my code books nothing in that area has changed. branch circuits have to carry there load. this would be considered a circuit extension if not a tap. and a circuit extension can be no smaller than #14 and efficient enough to cary the load.
 
jjflash said:
they whole point is its sufficient to run 1 light and you can't add anything off of the bathroom itself. the load is very very small.
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You are once again missing a key point. Yes, a #14 is more than enough to handle the load you plan to impose on it. However, that is only half of the story. That only deals with normal conditions. But if the light fixture experiences a failure and you suddenly get a much larger current, a 20 amp breaker won't be able to keep the wire from overheating and starting a fire.

 
jjflash said:
they whole point is its sufficient to run 1 light and you can't add anything off of the bathroom itself. the load is very very small. next i will be told i can't down size my wire for motors. i learned this way from the dallas chief inspector. a good while back but looking in all of my code books nothing in that area has changed. branch circuits have to carry there load. this would be considered a circuit extension if not a tap. and a circuit extension can be no smaller than #14 and efficient enough to cary the load.
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It may be large enough to carry the load but it is still a non compliant install as mentioned many times above. Switch legs are part of the circuit that demands that 14 gauge wire be fused at 15 amps not 20 amps. I don't believe this install would satisfy the tap rules of art. 240. Art. 240.5 allows a tap for fixture wires not switch legs
 
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