Compaq//safety issues - test-drb@ccmp.vtda.org

23 Jul 1998

You will LART me for sure because of this question. Is it possible to
use the neutral side of a socket for ground? What, in fact, is the
difference? (dopeslaps start flying in)

...
 The best way is probably to use a proper isolating
transformer. In  other 
...
 words have neither side of the 110V going to the PC
connected to earth.

A cheater adapter is also fine, provided you connect the 'pigtail' to a 
good
...
 local earth point. Note that the fixing screw of the
outlet (and hence 
the mounting box/conduit) may not be earthed. Should be, but I'd not  put 
...
 my life on it.

  So, why have I never felt anything touching a PC
case? I've done it
 many times, I've touched insides many times, and I've never felt so
 much as a tingle. Would I be able to use a VOM to find this voltage? 
Depends on a lot of things - how well earthed _you_ are (if there's no 
way a current can flow through you, then you'll not feel anything). The 
values of the capacitors used - low enough, and the current will also  be 
...
 too low to feel. In practice, this should be the case,
but having seen  some
...
 cheap PC power supplies I'd not trust them. Oh, and
how sensitive you  are 
...
 to the current. 

In theory, if you connect one side of a high-impedance AC voltmeter to  a 
...
 local earth point (or, indeed, the neutral side of the
socket), and the 
other side to the PC chassis without an earth connection, you should be 
able to measure 55V.

-tony

______________________________________________________
Get Your Private, Free Email at http://www.hotmail.com