I have some new wiring runs and was doing some checking before
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
nothing was plugged into the GFCI outlets and and lamp sockets were
also empty. This was causing a reduction in voltage due to the battery
being loaded. 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. The GFCIs are
made by Pass & Seymour (also says Legrand on the box). Their website
doesn't address this issue. These are their "premium" line and have an
LED on the front. A Leviton GFCI without any LED shows an open between
the live and neutral.

I don't know if all the GCFIs I bought can be simultaneously defective;
or whether the LED or their current monitoring circuit us causing the
continuity. 360 Ohms seems an awfully low resistance to show to 120V
AC. Is the behavior under DC different than AC for a GFCI outlet? Seems
pretty spooky...

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.

Nexus7 wrote:
I have some new wiring runs and was doing some checking before
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
nothing was plugged into the GFCI outlets and and lamp sockets were
also empty. This was causing a reduction in voltage due to the
battery
being loaded. 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. The GFCIs
are
made by Pass & Seymour (also says Legrand on the box). Their website
doesn't address this issue. These are their "premium" line and have
an
LED on the front. A Leviton GFCI without any LED shows an open
between
the live and neutral.

I don't know if all the GCFIs I bought can be simultaneously
defective;
or whether the LED or their current monitoring circuit us causing the
continuity. 360 Ohms seems an awfully low resistance to show to 120V
AC. Is the behavior under DC different than AC for a GFCI outlet?
Seems
pretty spooky...


you might be seeing the load of the internal power supply inside the
GFI that power the GFI itself.

the DMM is probably seeing the completly discharged filter cap inside
the GFI which will charge up and draw less current when you connect it
to the AC line.

Mark

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

--- sam | Sci.Electronics.Repair FAQ Mirror: http://repairfaq.ece.drexel.edu/
Repair | Main Table of Contents: http://repairfaq.ece.drexel.edu/REPAIR/
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| Mirror Sites: http://repairfaq.ece.drexel.edu/REPAIR/F_mirror.html

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Important: Anything sent to the email address in the message header above is
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I received a reply from Pass & Seymour's technical support. As part of
their "line load reversal test procedure," there is a small resistor in
the GFCI that makes it trip when the outlet is first energized. I don't
know if this procedure refers to what happens when first energized, or
if it is some other test that is performed during the manufacturing
process.

In any event, I (bench) tested this on one outlet, then on the curcuit
described. All 3 outlets duly tripped and the lights came on. After
resetting, all are open between L and N, and the circuit is functioning
correctly.

Thanks to all those who replied.

Ross Herbert wrote:
Good to see you got it solved. Don't they provide a TEST button on
those units?

They have the test and reset buttons, but these only workwhen connected
to mains, and I was reluctant to do that until I understood the reason
for the continuity.

It is strange that the manufacturer doesn't provide that information
on a leaflet or instruction supplied with the GFCI. Perhaps you
should
suggest that they do so to avoid confusion and a repeat of the
problem
for others.

The leaflet went into some length about the line and load sides, etc.,
but nothing about this. I hope the tech supp rep alerts their
publication folk, because emails to them since I received the reply
have gone unanswered.

Now if you hadn't been so inquisitive you would have just powered it
up like anyone else and you wouldn't have been any the wiser as to
the
initial leakage reading.

I was testing my wiring and not the outlets, and it was refershing to
find that my stuff was actually OK!

Why do you have 3 GFCI outlets on the same circuit? Only the first one on
the line needed to be a GFCI and it would protect all the other outlets
after it. You could also use a single GFCI breaker and then all the outlets
on that branch circuit would be protected. At least that's the way mine
work.
I am glad to here you solved your problem though, I would have been
surprised as well at the reading. They really should document that.

Bill

"Nexus7" wrote in message
oups.com...
I received a reply from Pass & Seymour's technical support. As part of
their "line load reversal test procedure," there is a small resistor in
the GFCI that makes it trip when the outlet is first energized. I don't
know if this procedure refers to what happens when first energized, or
if it is some other test that is performed during the manufacturing
process.

In any event, I (bench) tested this on one outlet, then on the curcuit
described. All 3 outlets duly tripped and the lights came on. After
resetting, all are open between L and N, and the circuit is functioning
correctly.

Thanks to all those who replied.

"Ross Herbert" wrote in message
...

Sure, you can use a single GFCI (usually DIN rail mount) in the
distribution box to supply up to the maximum number of outlets on any
branch circuit. But, you can also buy GFCI outlets which fit the
standard wall outlet mounting box.
http://www.passandseymour.com/news/view.cfm?id=158

I suspect they were developed to make it easy to convert existing
outlets to GFCI protected circuits without interfering with the
distribution board wiring. It is certainly a more expensive way to go
compared to fitting a single GFCI in the distribution box, that's for
sure.

How it's done in the USA/Canada is that one GFI is put in an outlet box and
then a number of outlets are run from that so all those downstream are
protected.
--
N

Bill Renfro wrote:
Why do you have 3 GFCI outlets on the same circuit? Only the first
one on
the line needed to be a GFCI and it would protect all the other
outlets
after it. You could also use a single GFCI breaker and then all the
outlets
on that branch circuit would be protected. At least that's the way
mine
work.

I figured if I did it that way, diagnosing a trip or other condition
would required knowing about the upstream outlet. I tried to minimize
such "non-local" effects by just putting GFCIs anywhere that no major
appliances would be plugged in. They were $10 on sale anywway. It's
too bad I have keep some shared neutral circuits because of legacy
issues, another instance where you have to know about the entire system
to work on just part of it.

"Nexus7" writes:

Bill Renfro wrote:
Why do you have 3 GFCI outlets on the same circuit? Only the first
one on
the line needed to be a GFCI and it would protect all the other
outlets
after it. You could also use a single GFCI breaker and then all the
outlets
on that branch circuit would be protected. At least that's the way
mine
work.

I figured if I did it that way, diagnosing a trip or other condition
would required knowing about the upstream outlet. I tried to minimize
such "non-local" effects by just putting GFCIs anywhere that no major
appliances would be plugged in. They were $10 on sale anywway. It's
too bad I have keep some shared neutral circuits because of legacy
issues, another instance where you have to know about the entire system
to work on just part of it.

So, now you will have some random combinatino of GFCIs tripping, rather
than only one.

Realize that there is no guarantee that only the GFCI at the affected
outlet will trip!

--- sam | Sci.Electronics.Repair FAQ Mirror: http://repairfaq.ece.drexel.edu/
Repair | Main Table of Contents: http://repairfaq.ece.drexel.edu/REPAIR/
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| Mirror Sites: http://repairfaq.ece.drexel.edu/REPAIR/F_mirror.html

Note: These links are hopefully temporary until we can sort out the excessive
traffic on Repairfaq.org.

Important: Anything sent to the email address in the message header above is
ignored unless my full name is included in the subject line. Or, you can
contact me via the Feedback Form in the FAQs.

Sam Goldwasser wrote:
"Nexus7" writes:
Bill Renfro wrote:
Why do you have 3 GFCI outlets on the same circuit? Only the
first
I figured if I did it that way, diagnosing a trip or other
condition
So, now you will have some random combinatino of GFCIs tripping,
rather
than only one.
Realize that there is no guarantee that only the GFCI at the affected
outlet will trip!

I haven't been very clear in my wording, but the GFCIs are fed from the
same breaker. However they are in parallel across this set of wires,
and they connect to the wires only at the 'Line' terminals, not the
'Load' ones. I think in this situation each should trip iff there is a
leakage associated with the load connected to itself only.

"Nexus7" writes:

Sam Goldwasser wrote:
"Nexus7" writes:
Bill Renfro wrote:
Why do you have 3 GFCI outlets on the same circuit? Only the
first
I figured if I did it that way, diagnosing a trip or other
condition
So, now you will have some random combinatino of GFCIs tripping,
rather
than only one.
Realize that there is no guarantee that only the GFCI at the affected
outlet will trip!

I haven't been very clear in my wording, but the GFCIs are fed from the
same breaker. However they are in parallel across this set of wires,
and they connect to the wires only at the 'Line' terminals, not the
'Load' ones. I think in this situation each should trip iff there is a
leakage associated with the load connected to itself only.

Yes, that's correct.

--- sam | Sci.Electronics.Repair FAQ Mirror: http://repairfaq.ece.drexel.edu/
Repair | Main Table of Contents: http://repairfaq.ece.drexel.edu/REPAIR/
+Lasers | Sam's Laser FAQ: http://repairfaq.ece.drexel.edu/sam/lasersam.htm
| Mirror Sites: http://repairfaq.ece.drexel.edu/REPAIR/F_mirror.html

Note: These links are hopefully temporary until we can sort out the excessive
traffic on Repairfaq.org.

Important: Anything sent to the email address in the message header above is
ignored unless my full name is included in the subject line. Or, you can
contact me via the Feedback Form in the FAQs.