sci.electronics.basics
[Top] [All Lists]

Re: PCs plugged into power strip into ungrounded GFCI?

Subject: Re: PCs plugged into power strip into ungrounded GFCI?
From: "Ralph Mowery"
Date: Mon, 19 Jun 2006 02:06:15 GMT
Newsgroups: sci.electronics.basics
"jim" <0.jim.meyer.0@xxxxxxxxx> wrote in message 
news:1150679553.537492.46070@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
>
>> You really need a 3 wire system for the GFI to add much protection to the
>> electronics, and that is not going to do much  either way for equipment
>> protection.
>
> Huh?
>
> This is a rental and tearing up the walls to add a third wire earth
> ground isn't an option.
> As I understand it the danger of running a PC off an ungrounded outlet
> is that any voltage leaks in an unbalanced system will try to find a
> place to go and a metal PC (power supply, case frame, case) are the
> nearest place to hang out, causing anyone who touches the case to catch
> the volt - not to mention frying the innards of the PC.
>
> So sans a ground in the outlet will a GFCI protect the PC from getting
> fried? I thought that if there was a voltage difference between the
> neutral and the hot wire the GFCI would trip and shut down.
>
> Furthermore the surge protector would be a second line of defense for
> the PC.
>
> Is this correct?
> I'm not thinking worst case scenario here where my PC is hit by
> lightning or anything like that so a UPS seems over the top (read, I
> can't afford one).

I think I understand what you are asking now.  Without the ground wire going 
to the case, a short from the hot wire to the case could be dangerous to 
you.  Unless there is a current unbalance such as if you have the 
router/cable modem connected to the earth by the coax comming into it, the 
GFCI will not trip to save the computer as the current going out the hot 
wire is the same as the current comming back down the neutral wire.   The 
GFCI will protect you if the hot wire shorts to the case and you touch the 
case while you are grounded.




<Prev in Thread] Current Thread [Next in Thread>