Last week my UPS started bleeping, it starts at 7.15 am bleeps for about10 sec then again a couple of min later, then a third time a couple of min after that. It does the same thing in the evening but I have not kept track of the times. It is not low voltage as a DVM is reading 234v at the time. Any body out there know of the reason? I happens with two different makes of UPS so I dont think it is a UPS problem. Do they still switch streetlights on/off by nicking half cycles from the mains? That might be enough to trigger my UPS. Both UPS's are several years old and have been here most of that time. I live next door to the local sub-station and usualy have clean mains.