[PCR-1000] My Ground Problem

[pcr-1000@mailman.qth.net]

In a message dated 02/13/2002 8:24:51 AM Eastern Standard Time, 
tmgurley@swbell.net writes:

<< The computer is using the house wiring.  I jumped from the PCR 
 to the case of the PC and the hum  disappeared. >>

What do you think? Do I still have a hazard? 

Hi Ted....

Maybe yes ...maybe no...one thing you might check is to put a voltmeter 
between the PCR and the computer in place of the jumper....this will give you 
your voltage differential "above" "ground".  The problem becomes if your 
differential is too high you might have a bad "house ground"...this usually 
displays itself in "flickering" house lights when something "heavy" 
starts....like a washer or an oil burner....

If your "house ground" is bad...any short circuit will try to travel through 
your jumper through the case of your PCR to your outside ground...may not 
bother the PCR but who wants to find out? The jumper and ground cable would 
have to carry the current.

Check your "house ground" by finding the EMT or wire which goes from your 
electrical box to "earth"...probably a cold water pipe that goes through the 
foundation into the ground outside...make sure the connecter to the pipe is 
"clean" with no corrosion.  Check the outlet the PCR is plugged into from 
each spade side to ground to insure that the "high" side (120v) is on the 
correct terminal. 

Not a solution, I know...but something more to learn...

Good Luck

Roger
WA1KAT