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#42842 09/28/04 11:13 AM
Joined: Sep 2003
Posts: 650
W
Member
400.7(A)(8) would seem to permit both the supply to and the feed from the UPS to be a flexible cord. Clearly this UPS is intended to be used with flexible cords on both the input and the output

I do not see the use of a flexible cord in this situation as a problem, as long as all of the standard flex cord precautions are met. There are UL listed generator transfer switches that use a panel mount twist-lock inlet, and which are connected to the generator via a flexible cord.

The SDS issue is also a red herring, because most UPS devices are not galvanically isolated input to output, and are thus more like auto-transformers. Both ground and neutral continuity are maintained through the devices, and thus they are not SDSs.

-Jon

#42843 09/28/04 01:35 PM
Joined: Jan 2001
Posts: 1,044
Tom Offline
Member
I don't believe that a UPS is an appliance, other than built in losses, it does not consume power and it certainly doesn't wash my clothes or fry my food [Linked Image] .

Flexible cord is not a Chapter 3 wiring method and cannot be inserted into a branch circuit. Check out definitions of "branch circuit " and "appliance."

Tom


Few things are harder to put up with than the annoyance of a good example.
#42844 09/28/04 08:26 PM
Joined: Apr 2001
Posts: 518
J
Member
UPS installation can be complicated. To start with, the UPS is only PART of the system; just as inportant is the transfer switch.

OK, so your UPS needs to be addad to the circuit. Yours sounds small enough to easily fit into a pull box, and be hard-wired.
Larger units, which often have wheels, are commonly attached with SO cord. These cords are connected to the panel with strain-relief connectors, and hard-wired to the circuit.
For other applications -such as a means to attach a power cord to a trailer, the device used is called a "power inlet." It's kind of like a cover plate with a plug mounted in a recessed area. This allows you to push a cord cap onto it. The problem with a UPS is that these prongs will be 'hot' as long as the batteries have a charge.

The first thing to do is contact the UPS manufacturer, and find out what his reccomendations are.

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