APC SU3000RMXL3U Smart-UPS XL 3000VA

[Mirfster]

Continuation from another thread that I was hijacking... /Sorry @danb35

please call a licensed electrician, I wouldn't want your house to burn!

Yeah, original breaker and wiring was install by an electrician. I had it ran from my basement panel across the length of the house and then up to the garage. That is where I originally had the Server Rack stored. Electrician used a dedicated single two pole breaker and I had him install one of those "whole house" surge protectors. All this was done using 12 gauge wiring.

So when I moved my "Server Room" to the basement closet; it ended up directly below that upward leg of the run in the basement. I simply tapped into that and installed my main rack outlets in the closet. Using 12 gauge wiring.

I do agree that if it was a longer run 8 gauge would be better, but from the panel to the Server closet is ~ < 30' so 10 gauge should be fine.

Actual plug on the UPS is not molded; but the type that can be disassemble by removing the screws. While the UPS does "cold boot" fine, I will check to see if there is any issues with the wiring to the plug (with the batteries removed...). Heck, should grab my multi-meter and at least do a continuity test..

As it stands now, I know that trying to use the existing outlet (2 pole / 20 amp breaker with 12 gauge wiring) is not recommended and have stopped pursuing that (was just curios to get the unit to fire up like Danb35 did). I will wait until I get that 30 amp breaker in and dedicated outlet in place. In the end, I figure that even if it turns out that the UPS is faulty I still want that dedicated outlet in there for when I get/have a working ups.

Will be extra careful for sure, while I am comfortable with wiring; high voltage/amp electrical stuff is one of those things that scares the heck out of me. While I don't get too concerned when messing with a normal 120v/15amp outlet; mucking around in a panel is not something to be taken lightly at all. I will get the wiring ran and outlet set first then tap into the panel last. But will for sure cut off all electricity to the panel first when I am doing that part.

Update: Panel is actually out of slots for breakers... So should I consider swapping out that existing 2 pole 20 amp breaker and having it replaced with a 2 pole 30 amp? Will get the wiring replaced with 10 (if not 8 gauge) as well. Only thing that concerns me is that original breaker was put in as a dedicated one for the server rack and I don't want to jeopardize anything in there. Of course most (if not all) will be plugged into the UPS, but it is nice to have a standard outlet for non-critical stuff.

 

[danb35]

Why are you using 2-pole breakers for 120-volt circuits?

 

[Mirfster]

Why are you using 2-pole breakers for 120-volt circuits?

Actually I never requested it personally. I specified to the electrician what the intended purpose was and let them decide. Just did a visual of the breaker and this is what it looks like:

Search at Lowes shows it as a "Square D QO 20-Amp 2-Pole Circuit Breaker", wonder if I can actually get 240 out of it? Doubt it though, he may have simply isolated each pole to an outlet (there are two in the garage where it was originally ran)... Add it to my list of things to check with the multi-meter. ;)

 

[danb35]

That's definitely not the right way to run a 120-volt circuit, and it might not even be legal. Single-pole 30-amp breakers aren't used very often (because 30-amp 120-volt circuits are pretty much unheard of in residential construction), but you can still get them at the big-box stores, not to mention any kind of electrical supply place. For the 20-amp circuit, there's no sense at all in using the double-pole breaker--single-pole 20-amp breakers are as common as dirt.

 

[Mirfster]

Mulling this over now and will check the actual 12 gauge wiring. If they used 12/3 then I am thinking that they were being lazy and only wanted to do one pull for two pairs of outlets. That way they could use a common ground and/or neutral but split the poles for power. However, that would suck because if either outlet overloaded it would trip the breaker and down both outlets...

While I am not an electrician; I know back in the day the "questionable" low voltage cable pullers would try and pull crap like this where they ran one CAT5 cable and split the pairs for two drops. Which was BS since that is not correct and they still would charge the person for two drops even though only one cable was pulled.

Gotta find my receipt and double check; from what I recall this wasn't cheap (at least ~$1,300.00) which I ignored since I was in a hurry. Looking back I know I would have done it differently had I undertaken the task myself... :(

 

[Ericloewe]

All these issues make me like 230V installations with Schuko outlets rated for 16A that much more.

Instead of fancy 30A circuits, for us it's just another outlet.

While I am not an electrician; I know back in the day the "questionable" low voltage cable pullers would try and pull crap like this where they ran one CAT5 cable and split the pairs for two drops.

Oh, that one is still popular around here whenever there isn't a chance the work will be inspected for conformity with the telecommunications installation code.

 

[jgreco]

That's definitely not the right way to run a 120-volt circuit, and it might not even be legal. [...] For the 20-amp circuit, there's no sense at all in using the double-pole breaker--single-pole 20-amp breakers are as common as dirt.

What's almost certainly happened here is that the electrician went with a shared neutral, and chose a common trip circuit breaker because for many of the applications where a residential electrician would be deploying this sort of thing, a common trip or tied breaker would be standard (high power microwave, dryer, air conditioner, etc). In the commercial setting, it's fairly commonplace to see shared neutrals without tied breakers. When I had circuits added at my house, I hired the master electrician we used at the data center and he came out and installed a bunch of 20A circuits with shared neutral. The big advantage of shared neutral is that you're not filling conduit with as many conductors.

Now the thing is, code's evolved for residential wiring in the last ~20 years, and new circuits should be done with AFCI, which probably makes shared neutrals in a residential environment something that we'll be seeing less of. With an AFCI, the neutral is supplied by the AFCI device, so shared neutral strategies become very much less attractive for residential.

My guess is that the end result here is that the electrician who installed the device in question was either trying to follow some particular requirement that maybe I'm not aware of, or that he was doing what was familiar. A lot of what goes on in the NEC is common sense, but there's also a lot of rules that are derived from experience, meaning bad experience of course...

 

[rogerh]

I would also make sure any multimeter used for anything but the most occasional use on mains supply wiring is properly rated. And made by a manufacturer who doesn't think safety ratings are met by applying the CE mark stencil. And, if in doubt, wear eye protection and hold only the probes, not the meter. And never connect it before the breakers, where even more kA are available.

 

[danb35]

And made by a manufacturer who doesn't think safety ratings are met by applying the CE mark stencil.

That's why I like my Fluke meters (though my little Brymen is pretty nice too).