[RFI] ISOBAR

[Jim Brown]

On 9/16/2012 1:24 PM, Ed Douglass wrote:
> Would I be correct in thinking that an MOV device at the end of a branch circuit would NOT be bad news so long as all the computer and peripheral equipment Is plugged into the MOV device?

There would not be the potential difference problem, but the inherent 
problems of MOVs (lifetime, blowing up (they DO blow up if you hit them 
with surges at the 6kV that IEEE studies show can exist on interior 
wiring).

> I other words none of the computer equipment has a ground connection away from the surge protector.
>
> Can you think of a likely way in which we could fooled?  E. g. A drain wire in a shielded CAT-5 cable.

Although Ethernet line drivers and receivers may be isolated by a 
transformer, the high potential of a lightning event can (and will) arc 
across it and take out the equipment. I know of several instances of 
that happening, the guys suffering the events were engineers, and the 
CAT5 cable was NOT shielded.

73, Jim K9YC