Neutral at a sub panel.

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euboss

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I am trying to determine if a neutral is required at a subpanel that has only 2 pole breakers and the equipment does not need a neutral? as in HVAC equipment. My concern is if someone adds a 120 volt circuit to the subpanel they would only be able to connect the neutral to the EGC and potentially cause a hazard. My Inspector says it is required although i can't find it in the NEC .
 
If it's not needed then it is not required. If the inspector says it's required tell him to show you the article section. With that said it is a good idea for the reason you stated.

Roger
 
euboss said:
I am trying to determine if a neutral is required at a subpanel that has only 2 pole breakers and the equipment does not need a neutral? as in HVAC equipment. My concern is if someone adds a 120 volt circuit to the subpanel they would only be able to connect the neutral to the EGC and potentially cause a hazard. My Inspector says it is required although i can't find it in the NEC .
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Not required. It's a design issue so if they're not paying for it then you don't need to install it. Inspector is incorrect. As Roger suggested ask for the code section that requires it and wait. It will be a long wait. ;)
 
I agree. Not required but maybe a good idea.

The inspector is sort of right if it is HVAC equipment. A service outlet is required and it will be 120V, although it does not have to be on the HVAC equipment feeder.
 
It is required at the service so that may be where the inspector is confused. You can always label the panel 240V only or whatever the voltage is that you have there.
 
This is correct:
infinity said:
Not required. It's a design issue so if they're not paying for it then you don't need to install it. Inspector is incorrect. As Roger suggested ask for the code section that requires it and wait. It will be a long wait. ;)
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The only requirement is that a feeder neutral be sized for it's maximum load. If that's zero, so is the requirement.
 
I deal with this all the time with the energy storage systems I install, which do not require a neutral and are not allowed to have load circuits on the same feeder. Never been questioned by an inspector. In my case I will not add a neutral 'for the next guy' because he had better stay out of my panel anyway. Maybe your subpanel is different. Then again, maybe it isn't so different, if you're sizing it just for your HVAC loads and providing a warranty on your work... One thing we do is put a label on it telling people not to add or remove circuits.

Simply put, not your fault if someone later does something clearly wrong. Just depends how generous you're feeling, IMHO.
 
LarryFine said:
The only requirement is that a feeder neutral be sized for it's maximum load. If that's zero, so is the requirement.
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Just to clarify.... If the neutral load is more than 0 amps then the feeder neutral would have to be at least as large as the equipment grounding conductor.
 
I recently added 2 subpanels at a restaurant...
Both 100 amp 3-ph 18 space.

One is for (4) additional rooftop condensers for grab-n-go coolers. All 3-ph but I decided to pull a #6 neutral because I wanted to also take a 120v circuit for service receptacle. Plus, there's still a few spaces in that panel. No telling what they'll want next.

Second is for (5) 5000 watt patio heaters on (3) contactors. Again, I pulled a #6 neutral because I needed a 15 amp circuit for contactor coils. And there are spaces left in that panel. No telling what they'll want next
 
Dennis Alwon said:
Just to clarify.... If the neutral load is more than 0 amps then the feeder neutral would have to be at least as large as the equipment grounding conductor.
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correct.

I once ran a 600 amp feeder that supplied all three phase compressor loads, and a 120 volt light circuit and a 120 volt receptacle in the compressor area. Neutral was same size as the EGC in that one and still had quite a bit more ampacity than the max possible neutral load - but that is the requirement.

Had it been 277/480 feeder I wouldn't have run a neutral at all unless intending to supply some 277 volt loads.
 
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