Neutral Sizing Question

[dancase]

I've spent the last 2 hours chasing my tail through the code book trying to answer this, and for some reason I can't find an answer. I figured I ought to ask before I pull out the little bit of hair I have left.


We're putting in a pair of new residential HVAC condensing units and in the process relocating them to the other end of the house. I'm planning to use a small 3R panel at the new location for combination OCPD and disconnect with a conduit home run to the main panel about 40 feet away. The units both run on 240V single phase.

I also want to power the required utility outlet from this panel (with its own breaker). Since this outlet is the only 120V load present, it seems like a total waste to run a #6 or #8 neutral (and I'm spending MY money on this one, so waste is a no-no!). Since that outlet is the only 120V load present, would it violate any codes if I ran a #12 neutral ? I could also take that neutral direct to the outlet and bypass the neutral bar in the panel if necessary.

Thanks!

D.

 

[texie]

I've spent the last 2 hours chasing my tail through the code book trying to answer this, and for some reason I can't find an answer. I figured I ought to ask before I pull out the little bit of hair I have left.


We're putting in a pair of new residential HVAC condensing units and in the process relocating them to the other end of the house. I'm planning to use a small 3R panel at the new location for combination OCPD and disconnect with a conduit home run to the main panel about 40 feet away. The units both run on 240V single phase.

I also want to power the required utility outlet from this panel (with its own breaker). Since this outlet is the only 120V load present, it seems like a total waste to run a #6 or #8 neutral (and I'm spending MY money on this one, so waste is a no-no!). Since that outlet is the only 120V load present, would it violate any codes if I ran a #12 neutral ? I could also take that neutral direct to the outlet and bypass the neutral bar in the panel if necessary.

Thanks!

D.

You can use a reduced neutral sized per Table 250.122. See 215.(A)(2). You can not pass it through the panel (bypass the neutral bar) to the recep, just land it like you usually do. Then run a 14 or 12 neutral to the recep as required.

 

[Smart $]

The feeder neutral can be no smaller than the minimum required EGC size (Table 250.122).

The neutral for the 120V outlet must originate in the same panel as the ungrounded conductor.

An alternative is to pull a 120V #12 two-wire circuit out of the main panel along with your subpanel feeders. This circuit will pass through your subpanel, but you will pick up your EGC at the subanel grounding bar. This will permit you to omit the feeder neutral.