OOPS (was Re: power-fail monitor )

[Bob Haar CS50]

In article <34655 at cup.portal.com>, thad at cup.portal.com (Thad P Floryan) writes:
|> rhaar at rcsrlh.Berkeley.EDU (Bob Haar CS50) in <34900 at rphroy.UUCP> writes:
|> 	I made a test to see how long the UPS would last. After
|> 	charging the battery overnight, I unplug the UPS from the wall socket.
|>
=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
|> 
|> For YOUR safety, do not EVER unplug devices such as a UPS or SPS from a wall
|> socket to test them: you lose the protective grounding of the 3rd prong.
|> 
|> Instead, use a switchable power strip into which the UPS (or SPS) can be
|> plugged, then flip the strip's switch to OFF for testing the UPS (assuming
|> your UPS/SPS doesn't have a self-test switch).
|> ...<some text deleted>...

Thad is right. I made two major goofs in my posting. First, just because an 
electrical device is battery powered doesn't mean that you shouldn't be
careful with it. A UPS that can run a 300 watt 3b1 for 15 minutes has
plenty of energy
to cause serious accidents. Secondly, as Thad points out, unplugging the
power cord from the wall switch also disconnects the protective ground circuit.

	Bob Haar   CSNET: HAAR at GMR.COM  UUCP: uunet!edsews!rphroy!rcsrlh!rhaar
	Computer Science Dept., G.M. Research Laboratories
DISCLAIMER: Unless indicated otherwise, everything in this note is
personal opinion, not an official statement of General Motors Corp.