UPS Faulty?

[Anonymous user]

I have a SUA3000RMXL 3U 3000VA UPS which i got nice and shiny and new last week. Thanks to some help on here I now have it running the way I want it to be, but I have run into a problem

The rear of the unit has two rows of C13 connectors (the usual PC power connector) and one C19 connector.

I am still in the testing/commissioning phase so it's not yet hooked up to my production servers, but I have two test/dev servers I am using for this purpose. All of these use the C13 connectors.

If I plug anything into the bottom row of connectors it trips the input circuit breaker, which is a 32A MCB, a single pole breaker in the phase line which trips after a specific time delay. I have had the electricians replace it with a time delayed one (C) of the type normally used for motors and such and therefore capable of handling a high inrush current, but this hasn't solved the problem. With anything plugged into the bottom row the breaker trips after 2-3 seconds, as soon as I move the connection onto the top row it's fine. I haven't tried the C19 outlet yet but I'm worried. If the C19 outlet does the same thing then I am going to be getting the less pleasant side of my boss' demeanour when he discusses the money I've just spent on PDU's - prior to my current revamp the server power consists of dozen of standard extension cables stuffed down the back of the server cabinet! Yes I know it's not right, but a new struggling company cuts corners in the first few years, now I have budget to do it properly

So, is my UPS faulty, or is there some characteristic that I haven't taken into account, like the possibility of earth loops or whatever. I'm an electronic engineer so I understand the technical but I am not familiar with the internals of this UPS, or the method of output power distribution

regards

Alec

[BillP]

Both rows of C13's are connected to the same bus. There is no technical explanation as to why the row would make a difference, and we can't think of any failure mode that would result in this kind of behavior. At this time,  I'd have to think something else going on.

Does it happen no matter which server you plug in? Do you have anything else to try besides those two servers?

[Anonymous user]

I have made the following tests

Unplug everything from the UPS.

Connect only one single power supply server (call it Srv4) to the top row of C13's. Server is OK, supply is ok. Shutdown server and connect to bottom row of C13's, supply trips out.

Disconnect Srv4 and reset breaker

Connect a laptop charger (without the laptop connected) to the bottom row of C13's. The supply breaker trips. I've tried the same by rewiring a desk lamp with a 60W GLS lightbulb in it to a C14 plug. Top row is fine, bottom row trips the supply breaker as soon as I connect it.

Incidentally there is no power output on the bottom row. The top row measures 231V, the bottom row only 137V Phase - Neutral, and the same reading phase-ground

Will it invalidate my warranty if I have a peek inside?

[BillP]

Hmm, ok the 137V P-N and P-G does not sound good. Based on what you said now, something does seem wrong potentially with the UPS.

And yes, technically if you open your unit, you're going to void any warranty.

At this time, I don't think you've missed anything and we seemed to have eliminate one single piece of equipment as the cause. You may want to refer to local technical support in your region to review the case and provide a potential replacement unless they catch anything different. I've asked our Smart UPS escalation team here and we do not believe this is normal, especially since they outlets are on the same bus.

[Anonymous user]

I've mailed APC UK tech support, hopefully a resolution will be forthcoming

Shame, I fought tooth and nail for three years to get the budgetary allocation for this thing, finally succeeding after we lost almost two full business days rebuilding RAID arrays after a power failure, and now I can't play with my shiny new toy.

[BillP · Accepted solution]

Sorry

Hopefully they do agree it needs replacing and we did not miss anything and you get a shiny replacement to play with. I can't imagine what we've missed but I am based in North America so we don't have the international version to look at further or refer to. Even so, the team I have here to ask does support at the global level so that is where I've gotten my information from.