GFI Tripping

[Indycars]

I ran a new circuit in the garage that has quadriplex receptacle (one is switched) and four outside flood lights that are on a 3-way switch. The outside lights were existing lights that were are on a different circuit.

Every time I flip the GFI breaker on it trips, if the 3-way switches are set to bring the lights on. Since I have looked the circuit over many times to make sure its wired correctly, I decided to try a normal breaker instead and its works just fine. I had another new GFI, so I tried it with the same results.

I must have some current flowing on the ground conductor, since the current in the hot and neutral must be different to trip the GFI.

Any tips on how to trouble shoot this problem???


Rick

 

[Tom McDermott]

One possibility - did you wire the GFCI breaker correctly?

GFCI breakers require that the neutral return back through the breaker, not directly to the neutral bar. There's a connector on the breaker that you wire the neutral to, and a pigtail on the breaker that goes to the neutral bus in the breaker box.

 

[tcianci]

check out the condition of the existing outdoor fixtures too

 

[Indycars]

Tom,

Sometimes I do things right....yes I made sure that black went to the load, white to the neutral on the breaker. The pigtail went to the ground buss.

Thanks for the feedback thou, you just never know.

tcianci,

That's a good idea, will give that a try when I get home today. I guess I could unscrew all the outdoor lights, then energize the circuit, then screw the lights in one at a time until the GFI trips again.

Thanks!


Rick

 

[mrb]

you mentioned the outside floodlights were on an existing circuit, and you moved them to the new one. Is there any chance the neutral from the existing floodlights isnt connected to the neutral for the new circuit, or the neutral from the old circuit somehow got tied to the neutral for the new circuit?

 

[VACharvel]

There's a dead-short someplace is my first assumption...it could be a faulty GFCI. Unleass you meant that the GFCI portion of the circuit just "popped" out sensing a fault.

GFCI's monitor the current between the "hot" and "Neutral" and will trip if they "see" a difference of between 4 and 6 miliamps.

I'd start by removing first one GFCI, test the circuit...if it clears there is your culprit most likely...then do it for the second if the first is OK....

Work your way from the "problem" back to the panel is my best advice.

 

[Indycars]

you mentioned the outside floodlights were on an existing circuit, and you moved them to the new one. Is there any chance the neutral from the existing floodlights isnt connected to the neutral for the new circuit, or the neutral from the old circuit somehow got tied to the neutral for the new circuit?

I have done several things, so I can't be completely sure until I get home. I believe that the neutral from the 12/3 that runs from the first switch to the second switch is connected to the neutral from the lights. Will verify tonight.

As far as the neutral from the old circuit, it is not connected to anything at this time.

Your help is much appreciated!


Rick

 

[Indycars]

There's a dead-short someplace is my first assumption...it could be a faulty GFCI. Unleass you meant that the GFCI portion of the circuit just "popped" out sensing a fault.

GFCI's monitor the current between the "hot" and "Neutral" and will trip if they "see" a difference of between 4 and 6 miliamps.

I'd start by removing first one GFCI, test the circuit...if it clears there is your culprit most likely...then do it for the second if the first is OK....

Work your way from the "problem" back to the panel is my best advice.

I put a standard breaker in place of the GFI breaker and it works then. I also replaced the first new GFI breaker with another new GFI breaker, but had the same problem.

Thanks for the help VACharvel!


Rick

 

[rodnok1]

I have a light if it's not screwed in tight i'll will pop the gfci, same for a flourescent light I put in the house, damn thing popped the gfci, took out and re seated the bulbs and its ok now.

 

[Indycars]

I have a light if it's not screwed in tight i'll will pop the gfci, same for a flourescent light I put in the house, damn thing popped the gfci, took out and re seated the bulbs and its ok now.

Good to know, thanks for the input! I hope you are right, sure would be an easy solution. I like those kind!!!


Rick

 

[oleguy]

turn breaker off.disc neutral from breaker.not the pig tail.with an ohmmeter,go to ground and ckt neutral.if you see continuity ,that is your problem.some times the bare neutral will touch the ground when wires are folded in a box.

 

[Tom McDermott]

Tom,

Sometimes I do things right....yes I made sure that black went to the load, white to the neutral on the breaker. The pigtail went to the ground buss.

Thanks for the feedback thou, you just never know.


Rick

Hi Rick. Is that a typo, or did you connect the pigtail to the ground buss? (The pigtail goes to the neutral bus.)

-- Tom

 

[oleguy]

hi rick. Is that a typo, or did you connect the pigtail to the ground buss? (the pigtail goes to the neutral bus.)

-- tom

if it is in the main panel,ground buss/neutral buss is the same.if it is in a sub panel,then you are right.

 

[Indycars]

turn breaker off.disc neutral from breaker.not the pig tail.with an ohmmeter,go to ground and ckt neutral.if you see continuity ,that is your problem.some times the bare neutral will touch the ground when wires are folded in a box.

Nice trouble shooting tip, thanks oleguy!


Rick

 

[Indycars]

Hi Rick. Is that a typo, or did you connect the pigtail to the ground buss? (The pigtail goes to the neutral bus.)

-- Tom

if it is in the main panel,ground buss/neutral buss is the same.if it is in a sub panel,then you are right.

This service panel is connected directly to the meter, so the ground and neutral buss are the same. But keep the ideas coming. Thanks!

 

[Tom McDermott]

Thanks, oleguy, I had asssumed a subpanel...

Two other possibilities:

1) The neutral and ground are shorted somewhere downstream of the breaker (the in-wall wiring or outlet boxes), or the neutral and ground are swapped downstream. Unfortunately the inexpensive 3-neon-light testers won't identify this problem.

2) The neutral is a 'shared-neutral'. This can happen for example on a 3 wire + ground circuit (2 hots, neutral, ground). The shared neutral has current from the opposite leg of the service and that trips the GFCI. Newer wiring requires the two breaker sides to be tied with a common trip handle, but on older wiring there may not be that common trip handle to give you the clue about what's going on. Also, it may be possible that someone wired a shared neutral somewhere downstream (even for the same leg) where's it's nigh-impossible to find.

 

[Indycars]

you mentioned the outside floodlights were on an existing circuit, and you moved them to the new one. Is there any chance the neutral from the existing floodlights isnt connected to the neutral for the new circuit, or the neutral from the old circuit somehow got tied to the neutral for the new circuit?

MRB, your comment above about the neutrals made me think about the two circuits coming into the box. I have attached some pictures.


The new power comes to this box first and then goes to the 4 gang box shown below. Therefore the power leaves on the WHITE wire.


Here you can see the power for the new circuit coming in on the white wire w/ black marks. There is also a 2nd power circuit in this box. All white neutrals connect together. I used a pigtail from the *********** conductor to bring power to the FIRST 3way switch (see labels in pic).

The 12-3 w/g leaving this box and going to the second 3way switch connects the white neutrals together with the lights, will this work???


Just another view of the 4 gang box, thought it might be helpful.

Do I have a problem with the *********** conductor???

Last night I did some checking with the outside lights. If any ONE light was in its socket, then the GFCI would trip. I'm thinking that the lights are NOT the problem, but something with the way I have wired the circuit.

To reiterate, if I replace the GFCI with a standard breaker, everything with the 3way switches and outside lights works fine. But I'm assuming that this is not a safe situation, plus it would NOT be to code since this is in the garage.



Any comments are appreciated!!!


Rick

 

[VHF]

There is also a 2nd power circuit in this box. All white neutrals connect together.

If the neutrals from two circuits connect together, that would be the problem. The neutral on the GFCI-protected circit must be isolated so that 100% of the return current on the neutral flows back through the GFCI breaker.

Otherwise, some of the return current flows back through the other circuit's neutral so the GFCI sees an inbalance then trips.

 

[mrb]

you say you have power running from the first box to the second on a white wire. Where is the neutral for this circuit then? I am a bit lost as to what you have going on.....

 

[Indycars]

If the neutrals from two circuits connect together, that would be the problem. The neutral on the GFCI-protected circit must be isolated so that 100% of the return current on the neutral flows back through the GFCI breaker.

Otherwise, some of the return current flows back through the other circuit's neutral so the GFCI sees an inbalance then trips.

Ok, I fully understand the problem now, but I'm confused about how to solve the problem. The only white wire from the correct circuit that I can connect with is carrying power. I can't connect the white wire bringing power from the receptacle with the white wire in the 12-3 w/g going to the second 3way switch (Not shown in any picture)...... Right???


Rick

 

[mrb]

Ok, I fully understand the problem now, but I'm confused about how to solve the problem. The only white wire from the correct circuit that I can connect with is carrying power. I can't connect the white wire bringing power from the receptacle with the white wire in the 12-3 w/g going to the second 3way switch (Not shown in any picture)...... Right???


Rick

how does the new circuit (hot and neutral) run from the GFI breaker to the first and second boxes?

Here is what you need:

GFI breaker ---black/white----->(outlets?)----->(3way Switch)----black/red/white------>(3way switch)---black/white--->(lights)

 

[Indycars]

you say you have power running from the first box to the second on a white wire. Where is the neutral for this circuit then? I am a bit lost as to what you have going on.....

Going from one of my wiring books. There are two ways to wire a switched receptacle, one by going to the switch first and another by going to the receptacle first. If I go to the receptacle first, then I can use 12-2 all the way. If I go to the switch first then I will need to run some 12-3. I chose to use 12-2 all the way, therefore I went to the receptacle first. Since I went to the receptacle first, according to my book the power going back to the switch (in the 4 gang box) would be on the white wire. That's why I marked the white wire with black in the 4 gang box.

I looked at the first picture some more, but its hard to see everything to give you more details. So I will have to look closer when I get home.

Guess I will have to revisit that part and make sure I have it done correctly.

Thanks again, I think we are getting closer!!!


Rick

 

[mrb]

the wiring order I posted was considering the outlets were always on. I am still not 100% clear on exactly what you have going on. The bottom line is the neutral for anything supplied by the GFI breaker needs to be the neutral that comes out of the GFI breaker. This neutral cannot be connected to anything else.

You're going to need 12/3 either way. If you go to the outlet first, you will need the third wire to bring the switch leg back to the switched outlet. If you go to the switches first you will still need 12/3 back to the outlet for the same reason.

I attached a crude drawing, it has the feed going to the switch, but you can bring the feed to the outlets and everything else stays the same.

 

[mrb]

another thing; even if you eliminate the problem by losing the GFI breaker and installing gfi receptacles, you will still need to correct the wiring as you cant steal the neutral from another circuit or cable as it appears you are doing now.

 

[Indycars]

MRB,

I have printed your dwg and will take a closer look at the details you have suggested. Will try to let you know something tomorrow.


VHF,

Looks like you were on the right track too!!!



Rick

 

[Indycars]

This is the dwg that I used to wire my switched receptacle. It only shows 2 wire cables and the reason I chose to go to the receptacles first, then to the switch in the 4 gang box. Both duplex receptacles shown here are in the same box shown below in the next picture. When the white/black wire get to the 4 gang box, I pigtail it to supply hot to my 3 way switch common terminal(Shown in 3rd picture).


Since I don't have a 3 wire cable, the white becomes the hot going back to the standard switch(Shown in 3rd picture, far left switch). Only the top half on the right receptacle is switched. If I understand MRB's suggestion, this white wire would become my red conductor in a 3 wire cable and white would remain as the neutral for this circuit.


In this 4 gang box the the neutrals for the two circuits would be kept separate from each other.

I know this is going to be very hard to follow from a distance, so I understand if you can't spend the time to get your head around this again today.

Once again thanks so much for the help from MRB and everyone else that gave feedback, another perspective is always a help!!!


Rick

 

[mrb]

This is the dwg that I used to wire my switched receptacle. It only shows 2 wire cables and the reason I chose to go to the receptacles first, then to the switch in the 4 gang box. Both duplex receptacles shown here are in the same box shown below in the next picture. When the white/black wire get to the 4 gang box, I pigtail it to supply hot to my 3 way switch common terminal(Shown in 3rd picture).

and there is your problem. You arent bringing neutral from the GFI circuit into the switch box. You are tapping the hot for the 3way to the outside lights and these lights are getting their neutral from another circuit which is causing the GFI to trip. This is what I suspected when I first posted in this thread.

The difference between the drawing you used and your situation is that you are taking power off in the switch box. The drawing only shows the switch, thats how you get away with 2 wires at the switch. Did you look at the drawing I provided? You need 3 wire between the outlet box and switch box.

 

[Indycars]

and there is your problem. You arent bringing neutral from the GFI circuit into the switch box. You are tapping the hot for the 3way to the outside lights and these lights are getting their neutral from another circuit which is causing the GFI to trip. This is what I suspected when I first posted in this thread.

The difference between the drawing you used and your situation is that you are taking power off in the switch box. The drawing only shows the switch, thats how you get away with 2 wires at the switch. Did you look at the drawing I provided? You need 3 wire between the outlet box and switch box.

Yes I have printed out your drawing and will run a 3 wire cable this weekend.

Many thanks again for all your help!!!

 

[mrb]

dont forget to seperate out the neutral that supplies the outdoor lights and connect it to the neutral in the 3 wire cable. This has to be kept seperate from the other neutrals.

 

[Indycars]

We have lift off !!!

It works with the GFCI breaker installed. The fix was not totally painless, working with all those wires in the 4 gang box was not fun. Like you said MRB, I had to isolate the white neutral wire from the outside lights. Pulling the 12-3 w/g was easy and a very short one.

Special thanks goes to MRB for all his help and to everyone that responded.


Rick