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View Full Version : Crazy Hour with CJ: Any electricians in the house?



-cj-
10-11-2011, 01:09 PM
Hey guys,

I wanted to build a poor man's centralized UPS system. I got a great deal on a UPS which I recently discovered is expandable with external battery packs. So what I wanted to do is, create outlets and "hard" wire them into the UPS (I'm not going to open up the UPS, just going to use something like a NEMA 5 (?) plug and hook it into the UPS. The other end of the plug will be hard wired into a standard house-hold 120V/15A outlet and essentially create that circuit. I thought it would look cleaner then just having power bars, since the UPS I have only has a handful of UPS'd outlets. Note that I won't exceed the UPS' load rating...

I don't think the above would violate any wiring codes. The UPS has a built in circuit breaker in case I overload the circuit... But I'm willing to incorporate a sub panel into the mix, just for fun.

Now, if I were to add a sub-panel, with the above setup, would everything be cool? Would an inspector see it and think "Wow, what a waste of time/money" or would they flag it? If the above is kosher, what would happen if I took a circuit from my main panel and ran it directly through this new sub-panel which is being fed from the UPS (which in turn is being fed from the main panel)? I don't see that being acceptable, although it would be ideal......

(I'm in the process of mounting my equipment to the wall in the basement and thought this would be a nice finishing touch... I'm used to building datacenters and I'm exposed to this sort of thing in the commercial sector (only with proper gear ;), but I'm curious if I could do this without violating any building codes... I'm pretty sure the second scenario above would violate something, right?)

I know, I know, it's a waste of time, but I'm trying to clean up my equipment and make it look cool.

To recap:

Scenario 1:
Main Breaker -> Outlet -> UPS <- NEMA Plug -> New Outlets Fed by UPS

Scenario 2:
Main Breaker -> Outlet -> UPS <- NEMA Plug -> Sub-Panel -> New Outlets Fed by UPS'd Sub Panel

With Scenario 2, I might re-route a single circuit (which has a computer plugged into it, on the 2nd floor) through the UPS panel... I'm pretty sure this is automatically a wiring violation, right?

Note that the UPS would be "fixed" to the wall, next to the panel, if that matters.

xxSlidewaysxx
10-11-2011, 03:20 PM
Are you talking about feeding a circuit of your house through the UPS?? While it's possible, you need to ensure that the power won't backfeed the power grid<<< there in lies the no-no. But, you do not want to have 2 power sources for 1 circuit. Try to do a rough drawing of what you are talking about so we can be on the same page.

-cj-
10-12-2011, 12:47 PM
Here's a diagram. All this is taking place in the basement. Not running any outlets around the house. Just hard wiring new outlets which will in turn plug in to the UPS using standard NEMA plugs. I'm wondering if this will violate any code... Technically nothing is hard wired in the house. The only point where it gets questionable is "S2" where I introduce a sub panel and possibly move an existing circuit from the main box into this new sub panel... I can see that being a violation right away...

http://www.clubnet.org/~clave/TM3/power.jpg