Go Back   DIY Chatroom Home Improvement Forum > Home Improvement > Electrical

CLICK HERE AND JOIN OUR COMMUNITY TODAY...IT'S FREE!

Reply
 
Thread Tools Search this Thread Display Modes
Old 11-18-2008, 10:46 AM   #1
Newbie
 
Join Date: Nov 2008
Posts: 16
Share |
Default

GFCI Trips


Hope I can explain this clearly, as I am very new to working with electrical stuff. I have a GFCI outlet in my garage that is middle of the run and has two other outlets run from it (another outlet in the garage and one on my front porch).

I have 2 problems with this outlet:

1. While attempting to replace GFCI outlet yesterday (would not reset properly), I broke the ground wire right where the 3 ground wires entering the box are pigtailed. I really don't have enough slack to run a solid ground wire to the outlet. I did manage to slightly undo the pigtail and wirenut a bit of the same gauge wire into one of the grounds. Is this OK? Is there a better way? Am I violating codes?

2. The GFCI is middle of the run. I have the line wires going to the correct line holes. I have 2 seperate sets of load lines--one controls another outlet in the garage, the other goes to one (or more) outside outlets. If I connect just the line wires and test it, it is OK. If I connect the line wires and the load wires for the garage outlet, they both work OK. As soon as I try to connect the load wires for the outdoor outlet(s), it will not reset at all. Do you think it might be that the outdoor outlets might have some moisture in them? Could I have some bad wiring somewhere? Could my crazy rigged ground described above be throwing it off?

I'm pretty sure it is not the GFCI outlet, because I bought 2 new ones and they both do the same thing. Would it be better to replace the breaker witha GFCI breaker?

Thanks in advance for any suggestions. I'm at a loss and trying to avoid a pricy bill right before the holidays!

campbellpt is offline   Reply With Quote
Old 11-18-2008, 01:05 PM   #2
UAW SKILLED TRADES
 
Stubbie's Avatar
 
Join Date: Jan 2007
Location: Kansas
Posts: 4,989
Default

GFCI Trips


Quote:
Do you think it might be that the outdoor outlets might have some moisture in them?
Good possibility (check that first) from your description the problem certainly lies with that branch of the circuit. Anything plugged into those outside outlets? If so unplug them and see what happens. It is possible there is some other outlet on the load side your not thinking of ?.., lights or the like...so be sure that you aren't missing something plugged in elsewhere. In general check all outlet boxes on the problem branch for moisture or iffy contact of wires to the bare of each other or metal. If these things don't correct the problem then come back and we will tell you how to test the wiring. If nothing is plugged into these outside outlets then no current should be flowing in the wires ....unless there is contact with the hot wire letting a small amount of current flow to the neutral or ground wires. As a home owner that is inexperienced I don't reccomend you doing any hot (power on troubleshooting) other than voltage checks. As you know be sure to focus when you have the power on and when you have it off when your working on this.

So let us know what you find.



Quote:
Could my crazy rigged ground described above be throwing it off?
Nope


Last edited by Stubbie; 11-18-2008 at 01:23 PM.
Stubbie is online now   Reply With Quote
Old 11-18-2008, 01:25 PM   #3
Newbie
 
Join Date: Nov 2008
Posts: 16
Default

GFCI Trips


Thanks for your reply, I will check outside outlets for moisture (I'm at work right now).

I'm 98% sure there are only 3 outlets controlled by the GFCI in question--the GFCI itself, a second outlet in the garage, and one outdoor outlet (that trips the whole mess). I will check that when I get home as well.

I used to have a small fridge plugged into the GFCI, a stereo plugged into the other garage outlet, and low-voltage landscape lights on a timer plugged into the outside outlet (under a covered porch).

I unplugged everything before replacing the outlet in question, so I can't really point at any appliance.

Driving me crazy!

Last edited by campbellpt; 11-18-2008 at 01:30 PM.
campbellpt is offline   Reply With Quote
Old 11-18-2008, 01:39 PM   #4
Newbie
 
Join Date: Nov 2008
Posts: 16
Default

GFCI Trips


Should mention that house is fairly new (2005), and I've already replaced this GFCI outlet once.
campbellpt is offline   Reply With Quote
Old 11-18-2008, 01:47 PM   #5
UAW SKILLED TRADES
 
Stubbie's Avatar
 
Join Date: Jan 2007
Location: Kansas
Posts: 4,989
Default

GFCI Trips


Thats fine....if nothing is plugged in then you have a problem with the wiring or the outside outlet on the branch that causes the gfci to not reset. Keep checking back others may reply. If you are comfortable with a few power on tests we can go into that also.

If you broke a ground wire off it is very possible that you can get a push connector on it then a pigtail to the other grounds or connect the others into the push connector. You can get them at lowes or HD. They look like this. GFCI's take up a lot of space in a single gang box so it might be crowded but should work.


Last edited by Stubbie; 11-18-2008 at 01:49 PM.
Stubbie is online now   Reply With Quote
Old 11-18-2008, 01:50 PM   #6
UAW SKILLED TRADES
 
Stubbie's Avatar
 
Join Date: Jan 2007
Location: Kansas
Posts: 4,989
Default

GFCI Trips


Quote:
Originally Posted by campbellpt View Post
Should mention that house is fairly new (2005), and I've already replaced this GFCI outlet once.
Yep that's ok the gfci probably is not part of a restricted branch circuit. the gfci may not be the problem in this case....
Stubbie is online now   Reply With Quote
Old 11-18-2008, 02:29 PM   #7
Newbie
 
Join Date: Nov 2008
Posts: 16
Default

GFCI Trips


I would love to try some tests (this will bug me until I can get it working), you'll just have to keep the description simple. The only thing I've done so far is to use a multitester to check between hot black and white neutral (which seemed to skip around quite a bit in the 120 range). I'm reading up on some of its other functions right now.

Fortunately, the main panel is only about 3 feet away from this outlet, so it is easy to switch it off, mess withe the wires, flip it back on, and test. An unfortunate side effect of this is that I switched the circuit breaker on/off so many times in rapid succession that I did forget once....ouch. Glad this isn't 240.

Also, I got flustered at one point and I unhooked everything from the initial replacement GFCI without labeling. Thought I had them straight in my head, reconnected them wrong (or maybe just the neutral and ground got too close?), hit reset button and a big flash/spark. No shock to me, didn't seem to be any damage to the outlet (it functioned--or should I say failed to function--the same as it had been all along), the neutral line wire had some burnt-looking discoloration going from about 1/2 inch to 1 inch from the end--doesn't look like it went through. Still, I can hook up just the GFCI outlet and it works, I can add the other garage outlet and it works too, but the outside outlet, once added, prevents the outlet from resetting.
campbellpt is offline   Reply With Quote
Old 11-18-2008, 02:40 PM   #8
Member
 
Join Date: Jul 2008
Location: NW of D.C.
Posts: 5,990
Default

GFCI Trips


Going back to the conditions that existed in your first post, with the GF tripped, confirm that there is no voltage downstream of the GF (because it's tripped) and then measure the resistance between any known good ground and the hot side (short slot or black wire) of the line that keeps tripping the breaker.

If it's less than 120v/4mA = 30 kilo-ohms you've found the problem (assuming there is nothing plugged in this line).

If not, there may still be line-to-ground resistance that only shows up with 120v applied. That's another post.

BTW, the GF "does not know" about ground.
It only knows that, of the current that was sent out, 4 mA or more of it are not returning through the same line, and so this missing current must be giving someone a shock.
Yoyizit is offline   Reply With Quote
Old 11-18-2008, 03:07 PM   #9
Newbie
 
Join Date: Nov 2008
Posts: 16
Default

GFCI Trips


OK, just want to make sure I have this straight, because I'm (clearly) not too sharp with this stuff.

I am going to leave the circuit braker ON and leave the GFI tripped, then go to the outside outlet (the one that keeps tripping it) and use my my multimeter or noncontact tester to see if there is voltage (there should not be any).

Then I am going to use my multimeter set to Ohms (which Ohm setting I will need to check...still learning about my multimeter) and leave the circuit breaker ON and the GFI tripped. I'll put the red probe to the black wire/short slot and the black probe...maybe in the ground hole to an extension cord plugged into an outlet with a ground that I know is OK (there are no other outlets nearby close enough to use).

Check to see if it's less than 120v/4mA. If so, I found the problem?

Quote:
Originally Posted by Yoyizit View Post
Going back to the conditions that existed in your first post, with the GF tripped, confirm that there is no voltage downstream of the GF (because it's tripped) and then measure the resistance between any known good ground and the hot side (short slot or black wire) of the line that keeps tripping the breaker.

If it's less than 120v/4mA = 30 kilo-ohms you've found the problem (assuming there is nothing plugged in this line).

If not, there may still be line-to-ground resistance that only shows up with 120v applied. That's another post.

BTW, the GF "does not know" about ground.
It only knows that, of the current that was sent out, 4 mA or more of it are not returning through the same line, and so this missing current must be giving someone a shock.
campbellpt is offline   Reply With Quote
Old 11-18-2008, 04:17 PM   #10
Member
 
Join Date: Jul 2008
Location: NW of D.C.
Posts: 5,990
Default

GFCI Trips


Quote:
Originally Posted by campbellpt View Post
I am going to leave the circuit braker ON and leave the GFI tripped,

You can also turn off the breaker, for extra, extra reassurance that you won't pop your meter.
Some meters have built in protection against putting volts into the ohms circuitry.

then go to the outside outlet (the one that keeps tripping it) and use my my multimeter or noncontact tester to see if there is voltage (there should not be any).
So far so good.

Then I am going to use my multimeter set to Ohms (which Ohm setting I will need to check...still learning about my multimeter) and leave the circuit breaker ON and the GFI tripped. I'll put the red probe to the black wire/short slot and the black probe...maybe in the ground hole to an extension cord plugged into an outlet with a ground that I know is OK (there are no other outlets nearby close enough to use).

One probe to a known good ground (which is supposed to be the round hole in this same outlet) and the other probe to the hot side and you are looking for 30K or less.
120v/.004A is 30k, and ~.004A is the minimum necessary to trip the GF.
The built in test resistor in the GF that does this same thing is about 16k.

You're making me a bit nervous!

Check to see if it's less than 120v/4mA. If so, I found the problem?
Yes, and if not there may still be resistance issues with the cable. The leakage resistance of the cable may depend on the voltage applied, and an ohmmeter applies so little voltage that this effect won't show up.
In that case, people use a
http://www.inotek.com/Catalog/Photos/meggerMIT1020.jpg

If you can't get a megger there are ways to do this test with the current ranges on your multimeter, but you also need an external resistor.
BTW, is your multimeter protected on all/any ranges against overload? The manual will say so because this is a selling point.

One problem is that if you read infinite ohms, how do you know you're actually touching the (female) contacts inside the outlet? This is more difficult than it sounds.
My solution is to plug something in the dead outlet, pull the plug out 1/8" and touch the test probes to the (male) plug blades. You can then see when you are making a good connection.

Last edited by Yoyizit; 11-18-2008 at 04:49 PM.
Yoyizit is offline   Reply With Quote
Old 11-18-2008, 06:26 PM   #11
Newbie
 
Join Date: Nov 2008
Posts: 16
Default

GFCI Trips


I discovered that the load lines in question cover a total of 3 outdoor outlets (not just the one that I mentioned initially). None have anything plugged into them,

I have a Greenlee DM-20 multimeter (I tried to post a link but it won't let me). Just not really good at using it, and the instructions that came with it are terrible.

I'll try the test you described with the MM set at 20K.
campbellpt is offline   Reply With Quote
Old 11-18-2008, 06:55 PM   #12
Newbie
 
Join Date: Nov 2008
Posts: 16
Default

GFCI Trips


I can't seem to get any type of steady measurement to report back. I mean the numbers jump all over the place. Not sure if I'm just doing it wrong or what. Plan right now is to wait until daylight and rip open all those outdoor outlets and see what is going on inside. I will check back on here to see if there is anything else I need to be doing. Thanks for your help!
campbellpt is offline   Reply With Quote
Old 11-18-2008, 07:18 PM   #13
Member
 
Join Date: Jul 2008
Location: NW of D.C.
Posts: 5,990
Default

GFCI Trips


Quote:
Originally Posted by campbellpt View Post
I can't seem to get any type of steady measurement to report back. I mean the numbers jump all over the place.
If the ohm reading is steady with the meter leads touched together, then the meter is good.

You might have found an intermittent short. This could be hopeful.

Very unlikely is that there is still somehow some voltage in the wires; I don't see how this is possible.

Your meter can't read AC current; slight change of plans if a leakage test is necessary.

Last edited by Yoyizit; 11-18-2008 at 07:23 PM.
Yoyizit is offline   Reply With Quote
Old 11-18-2008, 07:33 PM   #14
Newbie
 
Join Date: Nov 2008
Posts: 16
Default

GFCI Trips


When I set it to 20K and touch the leads together, it goes from around 14 down to zero very quickly and stays at zero.
campbellpt is offline   Reply With Quote
Old 11-18-2008, 07:56 PM   #15
Member
 
Join Date: Jul 2008
Location: NW of D.C.
Posts: 5,990
Default

GFCI Trips


Quote:
Originally Posted by campbellpt View Post
When I set it to 20K and touch the leads together, it goes from around 14 down to zero very quickly and stays at zero.
Good. Everything is unplugged or switched off on this line, right?
You should read infinity (OL ?) from the hot cable lead to ground, same as if the leads were not touching.
I'd put it on the 200k ohms range, to start with.

If it reads infinity, or substantially more than 30k, the next step is the homebuilt "megger."
If it passes the megger test also then the problem is very likely not in the cable.


Last edited by Yoyizit; 11-18-2008 at 08:07 PM.
Yoyizit is offline   Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
GFCI intermittent nuisance trips jejm1975 Electrical 43 09-07-2008 09:18 AM
GFCI light switch trips once per night ???? mw6263 Electrical 11 07-25-2008 11:05 AM
Microwave trips GFCI on a different circuit! Frank Kolwicz General DIY Discussions 7 06-01-2008 08:48 PM
New GFCI Breaker trips with no load bmurphywa Electrical 6 04-06-2008 08:48 PM
GFCI Trips Overnight Jomby Electrical 5 12-13-2007 10:41 PM




Top of Page | View New Posts

Copyright © 2003-2014 Escalate Media. All Rights Reserved.