Re: [RML] Leaking current

Cary Hostrawser (caryho at ix.netcom.com)
Tue, 28 Jan 1997 02:14:47 GMT

In The Dawn of the Third Age tex1 <tex1 at airmail.net> woke me from my
contemplation by writing:
> Cary, I will have to say I can find no fault in your statement. I based my
>statement on text material which was used in a technical school for
>electricians. As for the test you mentioned I would have to agree that a
>directed short between the grounded and ungrounded conductors would trip the
>breaker, as well as melt some copper.
Shouldn't really melt the copper because GFIs trip so fast. That was
the whole idea in their development. The grounded outlet saved us by
tripping the breaker (or fuse) when used with a grounded plug. Didn't
help much when the device was plastic with an ungrounded plug. Besides
electricians don't really need to know why, just what the codes are
;`)
If they tried to teach all the why's who'd we get to pull the wires of
the correct gauge and grounded correctly, certainly not most engineers
;~)

>I was in such a
>hurry to poke Roy in the ribs that I did not fully contemplate the situation
>before getting mouthy. As for that (as little as 1/1000th of an amp to
>ground will cause it to trip).
I can understand your hurry before somebody else grabbed the chance to
catch Roy, but he does give plenty of chances ;~)
The .001 amp sounds right. I believe that's the level of current
through the heart that can cause damage if sustained. And .01 amps I
believe was instant death. Its been awhile since I learned the numbers
and really don't like the idea of testing them.

>Your explaination sheds a little light on why it is so difficult to use a GFI on
>a magnetic load such as a transformer or flourescent ballast.
I had an electric razor that kept tripping the GFI when ever the cord
was giggled. I hated it when I went to shave after supposedly charging
it up only to find a dead battery and a tripped GFI.

>ps. can we talk about fish now?
I really wished I had one on a tank full of goldfish when the glass
broke and the florescent light fell in. I was one of those fixtures
with the ballast on the cord an not in the fixture. The breaker didn't
trip and all the fish had cooked for 2 days. The water was actually
boiling, with big, bloated, cooked goldfish bouncing around. The smell
was horrendous and drove me right back out ;~)

Later
Cary Hostrawser

Minnesota Aquarium Society
http://www.mn-aquarium.org/

Rainbowfish Study Group of North America
http://home.earthlink.net/~sbuckel/index.html