Well I installed a new GFCI as the very first receptical on a circuit
(added a new line cable from the panel, and the old line now becomes
the load coming out of the GFCI). My original questions and why I did
that can be found in this thread:
It looks like I installed the GFCI properly - resetting it works and
the light on it comes on. Everything downstream on the circuit works
(recepticals, room lights, etc) EXCEPT for a hardwired hallway light.
Turning that light on trips the GFCI. I can reset the GFCI fine after
that, but it will trip again if the light is turned back on. The only
unique things I can _see_ about that light is thats a 3-way.
Any suggestions? Probably not since thers very little information here.
Ill need to troubleshoot this more tommorow.
In my kitchen, my espresso machine is making the GFCI trip. When
plugging something else (such as toaster), it doesn't trip.
Also, plugging the espresso machine to another GFCI in my kitchen, it
doesnt' trip neither.
So is it due to the espresso machine or shall I just change the GFCI ?
Assuming the expresso machine is sitting on a nonconductive countertop
and it trips the GFCI as soon as you plug it in without you or anything
else touching it....
If it has a two prong plug it's probably the GFCI.
If it has a three prong plug it's probably the machine.
Like the previous poster said, try it on another GFCI, but not just
another outlet controlled by the same GFCI.
My guess is that the GFCI is OK and you have leakage either in the
downstream wiring or one of the appliances connected to the circuit.
GFCI's are calibrated to fairly tight tolerances and it just sounds
like it is working correctly and doing its job.
Remember, there are two ways a GFCI will trip.
1. A current difference in the hot and neutral wire of .005 A or
2. A downstream connection between the neutral wire and the ground
Many are unaware of condition #2, but this is the reason that there is
a 2nd toroidal transformer in the GFCI. Another safety feature.
I see two possible situation:
1) The problem GFCI is defective and needs replacement.
2) That GFCI is protecting other downstream circuits and
is detecting some minor GF problems from downstream.
The espresso machine may then become the "straw
that breaks the camel's back." GFs are accumulative
and the GFCI is effectively summing all of the GFs on
circuits that it controls. Note that the GFs may be
real problems or just so-called "nuisance" GFs.
Somebody really needs to market a plug-in device which measures
the level of GF for any device plugged into it. If anybody is aware of
a reasonably priced device that does this, please let me know before
I start building one.
Such a device should be pretty easy to put together with a portable
GFCI, a 120V outlet splitter which makes it possible to plug 2 loads
into the portable GFCI, a potentiometer for inducing a variable and
measurable GF, a fixed value resistor to limit the induced GF level,
a multimeter for a one-time calibrating of the potentiometer, etc.
Fred, you probably should buy or borrow a GFCI tester which has
user selectable GF settings. MCM Electronics sells such devices
and I'm certain that there are many others who sell this item. This
makes it possible to test your problem GFCI and to determine what
level of GF plugged into that GFCI will trip it. You can perform the
same test for the other GFCI in your kitchen.
Also, remember that GFCI units are relatively inexpensive and very
easy to replace. I paid $4.49 each for the most recent batch that
I purchased. To simply replace the GFCI and see what happens
may be the most pragmatic approach.
Let us know what you discover. We all appreciate the feedback.
thanks for your responses.
I installed a new GFCI, and it was still tripping.
I then tried again to plug it into the other plug I tried before, and I
realized it actually wasn't a GFCI (I couldn't see it as it was behind
a 2 -> 6 plug adaptor :-( Being in the kitchen, I just assumed it was
GFCI, but it wasn't).
So now I know my espresso machine is at fault.
I opened the expresso machine, tied all connectors I could find, tried
it again, and it made the GFCI tripped.
Next thing I tried: changed the cord. I had one at home, so simple
enough. One thing I wasn't sure about is that it had blue, brown and
yellow-green cables (the espresso is made in Italy), but the cord I had
was the typical black, white and ground.
I connected in: black/brown, white/blue and yellow-green/ground (found
that info on the internet)
When plugged in, it doesnt' trip anymore. However, if I activate the
pump, it trips again.
Any idea before I take it to repair. I probably should do that, but I
bought it used on ebay, not exactly for cheap, and sent it to repair
about 5 months ago (they cleaned everything), so my 10 years old
machine already cost me more than a new one :-(
I would hate to fork another $100 on it...
thanks in advance. Fred
It could be a problem with that hallway light fixture. I would remove it
and put a temporary pigtail socket in its place and go from there. I assume
the GFCI trips when the light is activated from either switch.
Most likely, "someone" used the "wrong" neutral when wiring the lamp.
It's not unusual to have more than one circuit appear in a box. It the
hall way fixture picks up a neutral that doesn't pass through your GFCI as
soon as you complete the circuit the GFCI on the "hot" wire will trip.
You can chase that down or just forget about running a string off one GFCI.
The GFCIs are relatively cheap. Just put in a GFCI for each outlet you
want protected and leave the string that goes to the hall light and switch
When you say "some used the wrong neutral when" do you mean someone
might have used a neutral from a different circuit?
I didnt wire this light - it was here when we bought the house, so I
have no clue how its done.
If this is the case - how could I go about fixing it?
Replacing all the outlets would be expensive up here in Canada (15
bucks a shot), and there are alot of outlets, so I would like to avoid
that if possible.
1) I can't guarantee that's the problem.
2) It's not important to GFCI a light circuit for a ceiling fixture.
3) If you think it's important, you likely will have to open up the
ceiling fixture box and the box where the switch is. You will have to
ensure that everything is wired as it should be. If you have a multimeter,
you can check for leakage paths and ensure that the neutrals and "hots" go
exactly where you expect.
But the other side of the coin is that if a GFCI "pops" because of the
downstream fault and you aren't home, your kids/wife/tenant/whatever may be
at a loss as to WTF happened.
Maybe in a compromise, you should just pull the fixture and see if there is
another circuit (don't forget that a switch loop will have a white wire
connected to a black wire at the fixture.
Finding the cause of ground fault tripping can sometimes tkae a lot of time.
It may come down to how much you value you time (including the time to do
the "mental work" on how to check the wires.
I took a quick look inside the two 3-way switches (one upstairs one
down). Just by looking at the wires I have a feeling the neutral is
from a different circuit (ie upstairs is all old cables, except the
switch has hot/neutral romex coming in).
Is there anything "wrong" with the way the person did this, if its what
you suggsted? Is it against code?
I hear you about the GFCI in the basement being a pain. I'll need to
look into this further tommorow, and decide if its worth the
effort/time to fix - otherwise I'll just put GFCI plugs in the
Thanks for your help.
It's "wrong" and it's against code.
But it isn't that big of a deal.
The problem is that the "code" saws that all the wires in a circuit are
supposed to be run together. Think of a cheap extension cord made of "zip
cord" wire. Were you to separate the wires the shock hazard would be about
the same as before but you end up with higher "stray" electro-magnetic
fields and in high current applications, metal objects that find themselves
between the two conductors might get warm. But it's to more of a safety
issue that the old style series Xmas lights from the 50s/60s or the series
street lights or series airport marker lights.
If you don't really understand the problem you will do more harm than good
in attempting to "fix" that which is only slightly broken.
Were it my house, I would likely figure out what mistake was made and see if
I can fix it. Or more accurately, I would have done that when I first moved
in and found such a problem. If I found such a "problem" today, I would
just ignore it and find something more important to fix.
That MIGHT work IF:
1) There isn't any "neutral sharing" other places in the house.
2) You have room in the panel
3) The "other circuit" isn't used for guaranteed "high leakage"
4) The owner doesn't get upset if two circuits go out from one
essentially harmless groud fault (a neutral to groud fault will also cause a
Frankly, the most cost effective approach is to only put GFCI outlets where
that type of protection truly increases safety. That's where folks might
end up touching a HOT wire while another part of the body is grounded. In
older homes, this means kitchens and bathrooms and basements and outdoors.
With plastic plumbing, the kitchens and baths are relatively safe.
your gfi has discovered an electrical problem in your home.
why your gfi trips is at:
good general faq including some gfi stuff at:
Usually, you put the GFCI on the wall in the bathroom, but it is not
used for general house wiring--- too sensitive. In this case, it may
have saved you future grief, by detecting a problem in the old wiring.
There may be break in the wire from a renovation, like a screw thru the
Find the problem before it starts a fire in the wall somewhere.
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