Background - We moved into our newly built home in late October of 1999. There are two receptacle circuits in our kitchen. Each consists of a twenty amp Cutler Hammer "CH" breaker leading to a GFCI receptacle at the counter with other outlets branching off the load side. One (breaker 26) has 2 load side recepticals (3 total incl. GFCI), the other (breaker 24) has 3 load side recepticals (4 total incl. GFCI).

The issue that follows is the circuit on breaker #26 which has 2 load side recepticals (3 total incl. GFCI).

Three days ago the breaker tripped right after starting up my 4-cup coffee pot. After un-plugging everything on the circuit I reset the breaker and tried to reset the builders GFCI outlet. It would not reset.

I had no spare indoor GFCI receptacles but did have a spare Leviton "wet weather" Cheetah W7599-TCW receptacle which I installed "temporarily" until I could acquire indoor units.

The circuit worked fine (self test LED was green) for a full day and the, night, and additional day until that evening when my wife was toasting bread in our toaster oven and she heard a "whoosh" (same noise she heard when the builders Leviton GFCI went bad). I saw the Cheetah outlet was dead (it's self-test LED was out). I unplugged everything from the Cheetah circuit and reset the breaker. When I tried to reset the Cheetah outlet there was a "pop" and a flash of light I saw through the receptacle cover. The breaker is once again tripped (CH breakers trip to "off").

Upon removing the GFCI I noted the line/load/black/white aspects were all correct. There was no damage evident to the wires, the receptical, or the box. All wires were securely screwed in place until removed. There "may" have been a slight mark of "soot" on one of the white wires.

Here is a link to a Picasa Web Album with Photos - https://picasaweb.google.com/BobTune...eat=directlink

I took some measurements on the wires -
SB = Supply Black "Hot"
SW = Supply White "Common"
GND = Merged grounds (crimped) wire in box
LB = Load line Black wire
LW = Load line White wire

SB->SW 123.5 V
SB->GND 123.5 V
SW->GND > 1 V (varying between 0.08 and 0.8 - visual estimate of digital reading)

SB->LB 110.8 V
SB->LB 110.8 V
SW->LW 2.8 V
LB->LW 0 V

Should I test the Cheetah GFCI by hooking it up to a cord and plugging it into a power strip with an integral breaker?

Any suggestions on how to proceed with the investigation would be appreciated.

 

Sounds like you have an intermittent short. I'd open up the other two receptacles and look for loose wires, wires stripped too far, nicked wires...that kind of thing.

You can try operating the GFCI with the load connections removed, but the GFCI may be toast.

 

Welcome to the forums.

You were very thorough in your testing. I have to agree with C.T.
Check for a downstream (load) short.

 

Yes, your testing was pretty thorough, but I still have a couple questions.

Tell me about how you did the testing and got that voltage reading between the black supply wire and the black load wire. I assume the toasty GFCI receptacle had been removed entirely from the circuit.....is that correct? Was anything else on the load side left plugged in and if so, was it turned on during the testing?

On the initial problem, the circuit breaker tripped and the GFCI receptacle tripped.....correct?

 

Good pickup Joe..... a voltage reading between the supply hot and the load hot could signify a short.

 

First - Thank you and all others who took the time to reply. This retiree appreciates it!

In reply to your questions -

1) To perform the tests I took the receptacle out of the de-energized circuit leaving the bare wires spread apart at the box opening. I energized the circuit and used my Harbor Freight digital multimeter (relatively cheap) to take the readings as indicated. I then capped of the hot wires and looped them back into the box, leaving the circuit energized just in case more readings were suggested.

2) In both instances the breaker tripped and I believe the GFCIs fried as well.

As suggested, I will open up the other two boxes in the AM and look for signs of a short. I was confused at seeing any voltage at all on the disconnected line and that could help explain it?!?

Thanks again.
- Bob

 

You weren't seeing voltage on the load side.

You were measuring from the supply hot (which should be live) to the load hot which should be completely floating but is not..... it's is grounded or touching neutral.

 

In looking at the numbers again, I guess this is the reading that confused me...
SW->GND > 1 V (varying between 0.08 and 0.8 - visual estimate of digital reading)

I didn't expect to see anything between white (common) and ground.

I'm just an old FIY computer geek trying to understand the numbers with 1's and 0's eyes ;-)

- Bob

 

Part of the problem is you are using a digital meter. An analog meter would probably showed 0. Except for very expensive digital meters with special circuits both capacitance and induction can cause a false reading with digitals because of their high impedance. However it could also be slightly higher resistance in the ground.

 

I removed the receptacles from the two boxes on the circuit.

Recepticle 2 - Wires and receptacle look and feel ok.

Receptacle 1 - Box looks ok, one black wire between this box and receptacle 2 appears to be damaged.

Here is a overview of the wiring in the box -


This is a closer view of the wiring in the box -


Here is a close-up of the damaged area of the wire -


I was able to get continuity on the wire by pressing the probe onto the damaged area of the wire -


Questions -
1) How do I repair this? Tape/Shrink/Tape? It's too short (no pun intended) to cut at the damage as it just extends to the outer edge of the box.

2) How do I prevent further damage? It looks to me like the end of the ground extending from the crimp is sharp enough to cut into the wire.

3) THE most important question - do you agree with my findings??? If I repair this, how do I test if the issue is fixed? Insert std receptacle in place of GFCI and run it a few days? None of these outlets are near the sink - would this be safe?

Thanks again for your help! I'll add these photos and others to the Picasa album linked in my original post.

- Bob

 

ray2047 - That makes perfect sense (a.k.a. sounds logical). Thank you for the explanation. We never need nor want to stop learning do we. Now all I have to do is remember it (getting harder all the time)!

- Bob

 

Heat shrink tubing is neater then tape but either can be used. I'd just put it together after fixing it and use it for a while.

I'd cut the ground connection and redo it using a green wire nut.

 

A push in connector could be used on the black after you cut out the bad spot.

 

I added a double layer of shrink tubing over the damaged wire and replaced the crimped grounding with the suggested wire nut (which I had on-hand from a different project).

My (hopefully) last questions are -

Is it OK for a short-term test to insert standard dulex receptacle in place of GFCI and run it a few days?

None of these outlets are near the sink.

Thanks again.
- Bob

 

After reading about lots of problems with the push-ins and having had one myself in our first home I felt the heat-shrink would be a better way to go. If there was more exposure or if I couldn't remove the suspected culprit (exposed sharp ground wire) I would have gone the cut route for the one wire.

Thank you for the suggestion though! I always appreciate suggested alternatives to choose from!
- Bob

 

Yup - I went with the heat-shrink and added a second layer.

I guess I misread this on the first pass... Were you saying to re-assemble using a standard duplex to test for a while?

Thank you for this for sure. It reminded me I had some from another DIY project! It looks and feels MUCH safer now. I just pulled the crimp off, rather easily, passed the long ground thru the hole and twisted... doesn't get much easier or neater than that.

Thank you again.
- Bob

 

Thanks for being the first to point out the load side short possibility. My mind hadn't gone in that direction yet and it looks like you were right on target.

I'm thinking you are right about the toast part, but will test it anyway. I just won't have high hopes when I do so.

Many thanks.
- Bob

 

No use a GFCI. That gives you a full test.The push in connectors PCBoss refers to are more robust and reliable then those on the back of receptacles.

 

My concern in using the GFCI as the initial test is frying a third one. If I start with a standard duplex I could use it a couple days to be sure I actually found the short, then put the GFCI in. None of the outlets in this circuit are closer than 4 ft from the sink and that one has a food sealer and a X10 lamp module occupying its ports. Not a good plan?

Are these referring to the receptacles with "clamp" style rear ports where the side screws close the clamp onto the wire? I'm looking to get a few of the "Commercial" grade outlets from HD tomorrow which, hopefully, will have that style connection.

I appreciate the help and education!
- Bob

 

Yes, I see your point using a non-GFCI receptacle and agree.No those are not push in connectors.



http://www.idealind.com/prodDetail.do?prodId=in-sure

 

I can't say I ever saw these Wire Nut alternatives before. Do you know if they've been proven to last longer than the 'back push in' connections on cheap receptacles?

I bought the outlets at HD today.


I'm not sure about the proper way to connect these. It looks like you put the wire under a small brass or copper 'clamp' just under the screw head and tighten down. Kind of an exposed version of the clamping mechanism on the last GFCI that got toasted.



I tried looking it up on the Leviton site but the only install instructions are to strip 3/4" of the wire.

Do I hook the wire or just leave it straight as done for the GFCI 'clamp' style connection?

Thank you (I hope you aren't tired of hearing this!).
- Bob

 

Leave straight and place under the clamp.

 

I will do so. Thank you once more.

Have a Happy and Healthy 2016 and beyond.
Wishing you all the best.
- Bob