120v ran through 480 disconnect

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tim89s

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Brush Prairie WA
I was told by a fellow electrician that it is a code violation to run 120v through a 480v disconnect for a roof top unit. The 480v and the 120v would enter the disconnect through the same conduit. The 120v would be for a GFI that would nipple to the disconnect using a bell box. The other electrician couldn't give me a code section but was certain it was a violation. If this is a violation could someone give me the code section.

Thank you
Tim
 
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Volta

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Location
Columbus, Ohio
It is not automatically a violation. Generally speaking, if the insulation of the conductors is rated for the highest voltage present, the main concern is one of crowding.
312.7, 312.8. Adequate space must be provided.
 
480sparky

480sparky

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Iowegia
300.3(C)(1) 600 Volts, Nominal, or Less. Conductors of ac and dc circuits, rated 600 volts, nominal, or less, shall be permitted to occupy the same equipment wiring enclosure, cable, or raceway. All conductors shall have an insulation rating equal to at least the maximum circuit voltage applied to any conductor within the enclosure, cable, or raceway.
 
infinity

infinity

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This is permitted by 312.8. IMO it would be hard to exceed the 40% fill requirement even if you tried. :roll:
 
e57

e57

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Location
San Francisco, CA
tim89s said:
I was told by a fellow electrician that it is a code violation to run 120v through a 480v disconnect for a roof top unit. The 480v and the 120v would enter the disconnect through the same conduit. The 120v would be for a GFI that would nipple to the disconnect using a bell box. The other electrician couldn't give me a code section but was certain it was a violation. If this is a violation could someone give me the code section.

Thank you
Tim
Click to expand...
As described - it is not... But the many "if's" that could be involved could make it one. Like if it interfered with the switching mechanism as mentioned by volta, or if the conductors had identification issues of the grounded, and ungrounded conductors (200&210), or if the nipple were above the live parts of the disconnect and were not sealed...
 
e57

e57

Senior Member
Location
San Francisco, CA
I think short of a picture we could only speculate.... But if we had a picture I bet we could find at least one violation - minor or preceived....
 
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tim89s

Member
Location
Brush Prairie WA
The outlet would not be turned off the by disconnect. My coworkers reason it was a violation was that if the breaker that fed the disconnect was turned off there would still be live voltage in the disconnect.
 
e57

e57

Senior Member
Location
San Francisco, CA
I'm sure there are some who reach for the virtual torque wrench everytime the see a terminal pictured on the screen in front of them. And find 2000 better ways it could be done from the comfort of a cushy chair 3000 miles away... :D
 
mcclary's electrical

mcclary's electrical

Senior Member
Location
VA
tim89s said:
The outlet would not be turned off the by disconnect. My coworkers reason it was a violation was that if the breaker that fed the disconnect was turned off there would still be live voltage in the disconnect.
Click to expand...



There is nothing stating that only one sourse pf power can be in that disconnect,since alpost all LTT disconnects have a souse of control power along with the 3 ph. He's not correct on that part
 
e57

e57

Senior Member
Location
San Francisco, CA
tim89s said:
The outlet would not be turned off the by disconnect. My coworkers reason it was a violation was that if the breaker that fed the disconnect was turned off there would still be live voltage in the disconnect.
Click to expand...
The same would be true for most/every junction box - and in itself is not a violation - the disconnecting means - does not require a disconnecting means of its own. But out of courtesy - marking the panel and CT#'s at the disco would be nice....
 
480sparky

480sparky

Senior Member
Location
Iowegia
tim89s said:
The outlet would not be turned off the by disconnect. My coworkers reason it was a violation was that if the breaker that fed the disconnect was turned off there would still be live voltage in the disconnect.
Click to expand...

There would still be live voltage in the disconnect without the 120v circuit being in there.

Weird. I turn off the main in a panel, and there's still energized conductors in it. How dare they!


So, turning off the main in the panel that feeds the circuit that feeds the disconnect would require turning off the power that feeds the main that feeds the circuit that feeds the disconnect.



My head hurts now.
 
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e57

e57

Senior Member
Location
San Francisco, CA
tim89s said:
The outlet would not be turned off the by disconnect. My coworkers reason it was a violation was that if the breaker that fed the disconnect was turned off there would still be live voltage in the disconnect.
Click to expand...
So that said - it is a code compliant and cost effective measure saving both a mounting means, and quite possibly a roof penetration specific to the required outlet. As I would have joined the two circuits in a box elsewhere - and brought it to the unit in a single conduit...
 
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