Question about NEMA enclosures

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Bluetec

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Location
Charlotte
Occupation
Electrician
I have a NEMA enclosure, located next to a main 200-amp CB panel, inside. The CB panel is fed from a standby generator transfer switch. Inside the enclosure are four (4) 220VAC, 50-amp, contactors with 24VAC coil voltage. The transfer switch controls the 24VAC coil for load shedding, in case the generator is active. The neutrals inside the enclosure are connected by neutral bus bar and insulated from the metal enclosure. The grounds are connected by bus bar in physical contact with the metal enclosure. The 220VAC contactors are for a well, electric dryer, range, and a subpanel box. When the generator is running and supplying power to the 200-amp CB enclosure, it can turn off the normally open contactors and resupply voltage to the coil, when power is available.

The problem I have is that, somewhere, in the NEC code, I read that inside an enclosure there can be no live, exposed, parts. The contactors are the same type that control an outside A/C condenser or heat pump. There is a warning on the box that there are live parts inside at 220VAC.

My question: Do the contactors need to be isolated, in a separate enclosure, that does not expose any of the live parts?
 

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jaggedben

Senior Member
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Northern California
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Solar and Energy Storage Installer
There appears to be a big violation here, which is that the neutrals for multiple circuits are improperly tied together on a neutral bar. (The ground bar is fine, but the neutral is not.) The installer needs to take the neutrals off the bar and splice the neutrals for each circuit together separately. (I suppose they could leave one circuit on the bar but seems like a poor practice that invites the same mistake later. I'd just remove the bar.)

Other than that I agree with the others there's nothing wrong with having contactors in a box. That's where this type of contactor is meant to go.
 

Fred B

Senior Member
Location
Upstate, NY
Occupation
Electrician
There appears to be a big violation here, which is that the neutrals for multiple circuits are improperly tied together on a neutral bar. (The ground bar is fine, but the neutral is not.) The installer needs to take the neutrals off the bar and splice the neutrals for each circuit together separately. (I suppose they could leave one circuit on the bar but seems like a poor practice that invites the same mistake later. I'd just remove the bar.)

Other than that I agree with the others there's nothing wrong with having contactors in a box. That's where this type of contactor is meant to go.
And it looks like the neutral bus is bonded to the box along with the grounds.
 

Bluetec

Member
Location
Charlotte
Occupation
Electrician
Thanks for the advice. The neutral bar was insulated but it was removed and the neutral wires are now spliced, for each, separate circuit.
 

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steve66

Senior Member
Location
Illinois
Occupation
Engineer
"Dead Front" enclosures can't have exposed live parts. For example, if you open the door to a panelboard, there shouldn't be anything hot you can touch. Once you take off the "dead front" by removing the screws (or even by lifting a cover off the hinges - tools aren't always required), then there can be exposed live parts.

Your box is not a dead front, so this doesn't apply.
 
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