actually, the usual switches these days on PC computers are only logic switches back to the power supply. The power supply does "tap into" the ac line to get a little power it needs. My P4 that I built last year uses an ANTEC case and there is no AC going out to a front panel switch - it is only a push button. A good rule of thumb is that if a switch clicks then it probably has AC on it. If it doesn't then it MIGHT be only low voltage. As an electrical engineer, I would not take the chance and assume it is low voltage without checking. Any computer that is pre-ATX will have AC voltage on the power switch. Some early ATX and maybe even now (I don't know for sure) may still have a real switch out front. The older mini-tower systems that have a power switch out front usually had a AC connector on the back of the power supply and a four conductor cable that ran out to the power switch. The power could tap into the AC line without affecting the switch out front. The older NEC, etc systems sometimes had a seperate power suply with an AC connector and cables, etc that were not integrated into the power supply like the PC, AT, ATX supplies that came along. best regards, Steve Thatcher On Wednesday 24 March 2004 23:45, William Donzelli wrote: position energized. off - instance). conductors?