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On Sun, Aug 20, 2006 at 11:47:09PM +0100, James Fidell wrote: > Adrian Midgley wrote: > > Paul Weaver wrote: > >> Common in telecoms apps rooms, everything runs off ~50VDC, backed up by > >> big batteries. Has a secondary advantage of being a "low voltage" device > >> and not needing the same testing as a normal apps room. > >> > >> > > > > Big high current DC supplies to several devices have their own > > interesting behaviours though, involving induction and possible high > > voltages when things are switched. > > And, according to a number of electrical engineers I know, they're a > much higher risk if they decide your body is a convenient conductor. But the chance of that happening is reduced. You can have upto 340V potential with AC, or 680V if you have a PSU fault with acapacitor. That's enough to break through your body fairly easilly. It's much harder for a 50V potential to break through. Obviously transfering the same power means that if your body does conduct, you'll have a much higher current, but then 1A or 6A, it's pretty irellevent. -- The Mailing List for the Devon & Cornwall LUG http://mailman.dclug.org.uk/listinfo/list FAQ: http://www.dcglug.org.uk/linux_adm/list-faq.html