Ross Herbert writes:

On 5 Apr 2005 07:51:02 -0700, "Nexus7" wrote:


Ross Herbert wrote:
On 4 Apr 2005 19:19:42 -0700, "Nexus7" wrote:
connecting to mains when I discovered that a 9V battery was pushing
25
or so micro-amps down a circuit that was supposed to be open, as

9V/25microamps = 360Kohms
360Kohms isn't going to load a 9V battery (unless it is already
flat).

The reason I said that is the voltage across the battery terminals is
more when it isn't connected to the circuit.

Looking further, I found that each GFCI (there are 3 in
parallel in this circuit) had continuity from live to neutral and
showed a resistance of about 360 Ohms on a DMM, causing about 120
Ohms
at the end that is supposed to go into the breaker panel.

This works out to about 30mA per GFCI. Sounds like the normal trip
current to me. ???

If it was the trip current, seems a little high... but the conditions
for tripping don't exist (as far as I can tell).

wiring has any insulation breakdown to neutral or earth. Test the
GFCI's while they are on the bench and see what you get.

The branches disconnected from the GFCI are open between L, N, and
ground. Continuity begins as soon as the GFCI outlets are put back into
the circuit.

The wiring itself should be ok then. Taking a look at the way a GFCI
works http://www-training.llnl.gov/wbt/hc/...GFCIworks.html
then with no load connected to the output of the GFCI then connecting
an ohmmeter across L - N at the input should read high resistance.

Sam Goldwasser has a page devoted to GFCI and their working so you
might get some further insight from there.

http://www.codecheck.com/gfci_principal.htm#top

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