4kVA UPS with Receptacle output

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ron

Senior Member
Vendor would like to run a branch circuit from the UPS output to other multiple receptacles in the building. The UPS only has receptacle outputs.

Anyone see a problem making up a plug on one end of MC Cable, and running it to several receptacles in the space?
 

don_resqcapt19

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Staff member
Location
Illinois
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retired electrician
Vendor would like to run a branch circuit from the UPS output to other multiple receptacles in the building. The UPS only has receptacle outputs.

Anyone see a problem making up a plug on one end of MC Cable, and running it to several receptacles in the space?
I have seen it done, but I would expect there would be 110.3(B) issues....I really doubt that an attachment plug is listed for use with MC, and there might be something in the UPS documentation that says for cord and plug connected loads.
 

texie

Senior Member
Location
Fort Collins, Colorado
Occupation
Electrician, Contractor, Inspector
Vendor would like to run a branch circuit from the UPS output to other multiple receptacles in the building. The UPS only has receptacle outputs.

Anyone see a problem making up a plug on one end of MC Cable, and running it to several receptacles in the space?

I have done it, but I think one could make a number of arguments about being compliant. In my case we installed a male bulkhead power inlet in a J box as the connection point to the fixed wiring.
 
I have done it, but I think one could make a number of arguments about being compliant. In my case we installed a male bulkhead power inlet in a J box as the connection point to the fixed wiring.
The bulkhead idea would make the in wall portion compliant. I wonder if the cord from the ups unit to the wall would be ok for permanent use.
 

tom baker

First Chief Moderator
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I have done it, but I think one could make a number of arguments about being compliant. In my case we installed a male bulkhead power inlet in a J box as the connection point to the fixed wiring.

That may be considered a violation, as you are using portable cord in place of the fixed building wiring.
There is a new provision in the NEC for a device such as you describe, but its limited to one outlet, and I can't find the provision at the moment
 

ron

Senior Member
I have seen it done, but I would expect there would be 110.3(B) issues....I really doubt that an attachment plug is listed for use with MC, and there might be something in the UPS documentation that says for cord and plug connected loads.

Good point. I guess I'm thinking now that they would have the plug on SO cord and the SO cord would enter a J-Box, where it would be spliced with MC cable on the other end.
 

ron

Senior Member
That may be considered a violation, as you are using portable cord in place of the fixed building wiring.
There is a new provision in the NEC for a device such as you describe, but its limited to one outlet, and I can't find the provision at the moment
It is interesting if you can find it for future reference, but in this particular case, the AHJ enforces NEC 2008.
 

winnie

Senior Member
Location
Springfield, MA, USA
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Electric motor research
I bet this could be a 650 post discussion.

Oh, wait:
http://forums.mikeholt.com/showthread.php?t=134709

Personally: I would be comfortable with texie's approach using a mounted inlet. The idea of putting a cord cap on MC strikes me as similar to making an extension cord using NM cable.

Another possibility: perhaps the UPS has a kit that permits hardwiring for both input and output.

-Jon
 

ron

Senior Member
Another possibility: perhaps the UPS has a kit that permits hardwiring for both input and output.

It does have a hardwire output option, but it has a 30A output protection, which means that I would have to breakout the circuit using a panelboard of some sort, I couldn't just feed a bunch of 20A receptacles.
 

jap

Senior Member
Occupation
Electrician
It does have a hardwire output option, but it has a 30A output protection, which means that I would have to breakout the circuit using a panelboard of some sort, I couldn't just feed a bunch of 20A receptacles.

But that would be the ticket.

JAP>
 

tom baker

First Chief Moderator
Staff member
That's the discussion I started and then based on that, a code proposal was made and accepted.
The easy way to do this is to use a UPS that is designed for a hard wired output.
 

fmtjfw

Senior Member
The idea of connecting the output of a UPS to fixed wiring (except in a computer room) really freaks me out.
I ran into a problem with an elevator control system that had an embedded UPS that energized fixed wiring external to the control box. It had 120VAC on a circuit breaker "tripped contact" in a nearby panelboard -- even after I had turned off all power to the control box.

Wiring UPS output to fixed wiring should, in my humble opinion require a marking on each cover plate on each box or other enclosure where the supplied wires appear that would read "UPS Protected". This would be desireable in terms of usability on the ultimate receptacle plates and serve as a warning on all the intermediate appearances. For the computer room you just put a sign on the door(s).

This addresses a real safety concern (especially when compared with the |0 (superimposed) on/off symbol for controlled receptacles).
 
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