John Summerfield wrote: > Mikkel L. Ellertson wrote: >> John Summerfield wrote: >>> In the event of a quake, it seems to me prudent to cut HT and mains, but >>> then generator sets automatically starting up would tend to negate the >>> action. >>> >> Not really - before you cut the mains, you switch the generator set >> control to off instead of auto. > > And if the power goes when nobody's home? > The same thing as happens if the power does not go out. Unless your generator runs out of fuel before the power comes back on. After all, if nobody is home, you are not going to cut the mains either. On the other hand, if you do not want the generator to run while you are gone, then turn the selector to off as part of the normal preparation for being gone for 2 weeks. You do do things like turn off the water heater, put the thermostat in the away setting, and things of that nature, right? > > I was away two weeks recently, and the power went while I was away. One > of the systems didn't come up, and when I got back a week later the > office had an evil smell, the smoke got out of a switch. > About the only change having an auto-start generator would be that your power would have been out for a shorter period of time, anything on a UPS would not have stopped running, the UPS batteries would not have gotten depleted, and maybe the smoke would not have come out of the switch. (Unless the delay before the generator started was longer then the UPS run time.) Most transfer switches are like most UPSs - line power has to be restored, stable, and within the proper range for a period of time before the switch to line power is made. This has an added benefit of protecting your equipment from line fluctuations that are common when power is first restored. I fail to see how a properly installed auto-start generator would increase your risk. The transfer switch isolates the generator from the outside power - there is never a connection between the generator and outside power. The only place they should meet is in the transfer switch, and that is configured so that only one can be connected to the load at a time, and the two sources can never be connected to each other. I can see how an improperly connected generator can cause problems, but that is a problem in any case. Mikkel -- Do not meddle in the affairs of dragons, for thou art crunchy and taste good with Ketchup!
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