North American Network Operators Group

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UPS failure modes (was: fire at NAC)

  • From: Robert Boyle
  • Date: Thu May 29 12:43:18 2003

At 12:27 AM 5/29/2003 -0400, you wrote:
Sheesh. Heh.

We're still here.

Part of a rectifier in a Liebert UPS let loose, causing a momentary fire.
That is, until the FM200 quenched it.

Since there seems to be interest, I will post the post-mortem to the list.
I had a little 2000VA rackmount Liebert UPS catch fire in 1997 and another new and improved Liebert model almost catch fire about a year later. Both were operating well within specified input, load, and temperature parameters. I haven't really trusted them since.I bought dual MGE UPSes for our datacenter in 2002. I figured if E****s can flip them on and off randomly and massively overload them all in an environment which is 95 degrees F, then they should hold up nicely for us when lightly loaded at 65 degrees F. :)

The reason for this rambling post is to ask if others have had similar problems with other UPS brands. I think they should have enough fail-safes built-in that they are never the CAUSE of an outage much less a fire! Based on my experience and NAC's incident today, is that an unreasonable expectation? I don't think manufacturers specify MTBF (mean time before fire) figures for UPS units. What have others experienced as the failure mode(s) for their UPS(s)? The static transfer switch should drop the load onto line/bypass power immediately and shut down the inverter while tripping the battery disconnect at the first sign of trouble - does this work as designed and advertised most of the time or just some of the time? Of those with UPS failure histories, what has happened in your situation?


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