On 5/29/2010 6:39 PM, Cliff Hartle wrote:
I installed my window air conditioner and the GFCI on the end of the cord
would not reset. I figured I would replace the plug and get an inline GFCI
to replace what was there.

I cut the plug off the end of the cord. As I was doing this I was wondering
how I would figure out which side was black and which was white. Well I
looked at the cut end and to my relief I saw a white, black and a green
conductor inside the sheath, OK a piece of cake.

As I cut back the sheath I found that the white and black wires were wrapped
with a copper shield like the outer conductor in CATV cable.

I was like what was I supposed to do with this shield. I cut it back the
"shield" to keep it away from the terminals, put the plug together plugged
into the GFCI and every thing worked.

So why the "shielding"?



Back in the early 1970's I worked for an electrical supplier when ground
fault breakers first became widely available. One of the problems with
the new fangled devices was RF sensitivity, the breakers would trip
every time someone keyed the transmitter on a ham or CB radio. It's
quite possible that the shielding is to prevent spurious tripping of the
built in ground fault for the AC unit. It may be that it is so sensitive
to RF from things like cordless phones or cellphones that the shielding
proved to be a necessity.

TDD