Downsizing Neutral

[Delta2518]

I have a project where I am feeding two saunas both a couple hundred feet away. They both require a 3-phase 50A breaker and requires a neutral for 120v coil contactor/controls and lights (taps off one of the hots in the sauna control box and theres a 2 amp inline fuse). The neutral does NOT go to the heater. I would like to downsize the neutral from a #6 (if i was sizing per the phase conductors) to a #10 (only 2 amps max on the neutral but keeping same size as EGC) but am having a hard time finding the specifics in the codebook and want to be sure on the rules as this is getting inspected. The plans do not specify size of conductors. If you guys could point me in the right direction it would be greatly appreciated! Thanks in advance.

 

[LarryFine]

Welcome to the forum.

It sounds like you've got it to me.

 

[Delta2518]

Welcome to the forum.

It sounds like you've got it to me.

I cant find the code section allowing me to do this, maybe I’m just skipping right over it? Ive looked through 220 and didn’t see anything for neutral sizing for branch circuits only for feeders..


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[LarryFine]

I got the impression you were feeding two breakers. Branch circuits are covered in Art. 210.

I scanned through it but didn't see anything specific.

 

[ptonsparky]

Make them feeders.

 

[Eddie702]

I don't think you will find permission in the code. The neutral only needs to be sized large enough to carry the load as far as I know

 

[LarryFine]

I still thing the same-size-as-required-EGC minimum applies, or should be applied.

 

[kwired]

I still thing the same-size-as-required-EGC minimum applies, or should be applied.

If it is a feeder yes, 215(2)(B) is where this is.

Branch circuits don't have a similar requirement and IMO OP could use 14 AWG if running a branch circuit.

Service conductors must have minimum grounded conductor sized no less than minimum required SSBJ.

 

[wwhitney]

Branch circuits don't have a similar requirement and IMO OP could use 14 AWG if running a branch circuit.

I don't see how that complies with 240.4. The neutral conductor's protection is dependent upon the OCPD for the associated ungrounded conductors.

For that matter, seems like 240.4 is missing the necessary permissions to take advantage of a downsized feeder or service neutral sized in accordance with 220.61.

Cheers, Wayne