Pilot light wire sizing

[raco232]

I am wiring up my lights in a workshop I had built and am running everything in conduit. I would like to have pilot lights at the switches, which are located at the main man door. I have (3) three way switches, that I would like a pilot lights installed. That way, I know when an exterior light is on and not have to happen to see that it is on when I am outside. My question is, what size of conductors do I need to run back to the pilot light from the switch leg of the light or the switch, depending on convenience. I have the lighting circuit on 20A circuit with #12 thhn wire. I'm not an NEC expert, but am quite familiar with the code book a40'nd it seems like that there is a variance of downsizing the wire size for pilot lights. Am I correct or do I just have wishful thinking? If I can downsize the conductors, what size am I am allowed to go to? The pilot lights will be of the led type. Cheers!

The reason for wanting to downsize from a #12 conductor, is that the conduits are fairly full and am just wanting an easier pull. The longest run is around 80' and the shortest is about 40'.

 

[sberry]

It's probably 16.

 

[walta]

To my ear, downsizing the wires without a fuse/circuit breaker to limit the current sounds like a recipe for a fire.

Should the pilot light fail in a way that connects its 2 wires together the full rating of the breaker will flow thru the small wire it would likely get red hot and start a fire before the breaker trips.

Walta

 

[alfredeneuman]

It's Table 430.72(B) in the 2017 NEC and the control wires extend beyond the enclosure, so it says you can use up to.
#18 with 7 amps
#16= 10 amps
#14= 45 amps
#12= 60 amps

For the 18 you'd have to use fuses, the 16 fuses or a 10 amp breaker.

 

[david5253]

Insteon keypads are what you need. They will show which lights are on or off without the need to run any additional wires. Google "Insteon"

 

[mm08822]

It's Table 430.72(B) in the 2017 NEC and the control wires extend beyond the enclosure, so it says you can use up to.
#18 with 7 amps
#16= 10 amps
#14= 45 amps
#12= 60 amps

For the 18 you'd have to use fuses, the 16 fuses or a 10 amp breaker.

Article 430 is only for motor related topics, so it doesn't apply to a general purpose branch ckt.

Article 240.4(D)(1) & (2) lists the OCP requirements for "small conductors" similar 430.72B for #18 and #16 only.

Article 310.106(A) lists the min conductor sizes for General wiring as #14 for most types of insulation. Any exceptions I found listed don't apply to OP's situation.

OP will need #12 if OCP =20A or #14 if OCP = 15A.

If the OP picks up the lighting loads all at one switchbox, then those 3 S3's could be piloted style but this might fall short of OP's plan.

 

[raco232]

I went ahead and ran #12 thhn and am done with it. It was tight, but did not exceed conduit fill in 3/4” emt. Thanks for all who replied!

 

[alfredeneuman]

Article 430 is only for motor related topics, so it doesn't apply to a general purpose branch ckt.

Oops, I thought he wanted pilots lights for his machines.
I reread it and saw that it was for lights.