UPS epo tripped

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bwyllie

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Called to a site where a UPS shut down w/ out a signal from the FM2000 panel or a remote epo button. There is an external relay cabinet within the UPS room and the relay that controls the epo function of the UPS has a contact that is normally closed. It is believed that some sort of vibration or accidental contact made the contact open and thus shut down the UPS. there were two techs in the room at the time but they say did not touch /bang anything.

Has anybody ever ran across a situation like this before? Any comments about the relay set up, another UPS manuf recommended that the contact should be normally open and would elminate an accidential opening like this.
 
The very few EPO buttons I've ever worked on, we ran the conductors through two or three sets of contact blocks on the back of the EPO button (in series) and wired as normally open. Maybe that was wrong, but I'm just passing along all I know about that.
 
The one EPO switch I worked on was also normally open. Remember a forman scanned it with a tic tracer, and with no chirping said, Ahh this is normally open, and told me to disconnect it, so we could replace the cracked lug next to it.

I told him nice try, but if that EPO circuit was less than 50vac or DC, your tic tracer reads nothing, it may be normally closed, and I offered him the honors of disconnecting it to find out.

After hems and haws he said screw it and yanked it. Come to find out the entire EPO and fire suppression system had been disabled during construction and maintenance. A very smart idea.
 
What type of UPS is it? Does it record any alarms and did the UPS record an EPO? Not all techs are honest when EPO's occur and they are in the room. Not saying this is the case, but I have never had a UPS alarm log lie to me. Is the EPO connected to anything else and did those systems shut down or record EPO's?
 
the UPS log showed that the UPS epo had been acticated, none of the other devices that would have shut down by the EPO button, such as ac units, did not shut down.
 
I have worked on numerous UIPS shut downs and been paid to try to figure why the system mysteriously shut down in EVERY circumstance it was operator error or intentional operation.

We had one customer that was losing their UPS once, twice a week, then they started losing non-UPS power I got suspicious, I had tested and monitored everything I could, as a last resort I suggested setting up a camera unknown to any employees. The boss objected swearing his employees were the best; it was his number two man.

Another time the UPS crashed once a week at night, once again tested everything and monitored loads, one evening we were there and the cleaning woman came in the power room to stash her trashcan and mop, she went for the EPO button, we had to find an interpreter to ask her why. She said she was ordered to turn off the lights when she left, she thought the EPO was the light switch (was sort of). We never could figure out how someone might be getting in the room as all keys were in a lock box, to enter the power room you had to use a pass card that logged you in and out, no body thought about the building master key, which for some reason she had.

When you get pulled over for speeding do you admit to the officer, ?yes sir I know I was doing 70 in a 25?? Most people lie about this and also lie about hitting an EPO, who wants to lose their job, especially if it was accidental.
 
These techs also told their mothers that they didn't write on the wall.

Interview them apart and compare their stories.

There are more complicated EStop stations that could be considered.
 
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