UPS Power in switchgear

[bnewport]

We are installing a UPS to feed existing loads. The feeder conduits are embedded in the slab, and come into the bottom of the switchgear. We need to refeed some of these loads from the new UPS. How do we tap into the existing panel feeds inside the switchgear? What code sections would apply? I can't see how this is possible without using the switchgear as a raceway for the UPS power. We also need to do the same thing with some of the branch panelboards, picking up only certain circuits. The work to be done is at a television station/studio, and they can't afford very much downtime.

bnewport@koontz-wagner.com

 

[ron]

Re: UPS Power in switchgear

If they can't handle too much down time, then bring your new feeders directly to the loads, have the raceway and circuitry complete, dress and prepare for termination, then the cutover to the new feeders will be short.

 

[jhines]

Re: UPS Power in switchgear

Look at NEC 373-8, handbook. If you need to, is there room to add an auxiliary gutter?

 

[iwire]

Re: UPS Power in switchgear

Originally posted by bnewport:
We are installing a UPS to feed existing loads. I can't see how this is possible without using the switchgear as a raceway for the UPS power. We also need to do the same thing with some of the branch panelboards, picking up only certain circuits.

Why can't you use the enclosures like a raceway as long as the space required by 312.8 is maintained?

312.8 Enclosures for Switches or Overcurrent Devices.

Enclosures for switches or overcurrent devices shall not be used as junction boxes, auxiliary gutters, or raceways for conductors feeding through or tapping off to other switches or overcurrent devices,unless adequate space for this purpose is provided. The conductors shall not fill the wiring space at any cross section to more than 40 percent of the cross-sectional area of the space, and the conductors, splices, and taps shall not fill the wiring space at any cross section to more than 75 percent of the cross-sectional area of that space.

Bob

 

[bnewport]

Re: UPS Power in switchgear

Thanks- 312.8 was the section I was looking for....

There is plenty of space for the new feeds and splices, but is it legal to bring the UPS power into the service equipment and make a splice? It is not really feasible or cost effective to run a new feed to the loads, due to distance and the number of existing panels to refeed, so we need to pick them up in the gear. There is not a real easy way to install a tray above the bottom feed conduits. Can we bring the UPS feed into the gear and splice in the gear, or does that UPS feed and splice have to be contained in its own raceway?

 

[bnewport]

Re: UPS Power in switchgear

How is this different than a control cabinet where some of the power is from a control xfmr contained in the cabinet, and some is foreign power?

 

[iwire]

Re: UPS Power in switchgear

I do not know of anything that would stop you from mixing UPS power and "normal" power as long as the UPS does not feed article 700 Emergency Equipment, which I doubt that it does or will.

There is this article to consider at your switchgear, read the exception.

408.3(A)(3) Same Vertical Section.
Other than the required interconnections and control wiring, only those conductors that are intended for termination in a vertical section of a switchboard shall be located in that section.

Exception: Conductors shall be permitted to travel horizontally through vertical sections of switchboards where such conductors are isolated from busbars by a barrier.