GFCI failure -- mystery...?
 

So I'm putting in a bathroom, and I installed a single outlet with a GFCI breaker for protection.

All is well for months. I use the outlet while I'm putting in studwalls. The drywall guys use the outlet for their tools. No problems.

A few weeks later, after we've painted the rest of the floor, done some plumbing, and a few other things, the outlet is dead. Some research shows that the breaker won't reset.

Right. First question: Where's the water? So I trace out the portion of the wire that I can still see (most of it is in the wall now), and it's all good. The outlet seems fine, but just to make sure, I pull it completely out of the circuit. So the next test is: Will the breaker reset with just the wire, no breaker. Answer: No.

So I changed out the breaker, and the new breaker worked fine. I shrugged and said, "That's $60 lesson in breaker selection. Odd, but I'm sure it's not unheard of."

That was two weeks ago. I've used the outlet half a dozen times since then. I checked it tonight and it was dead. Breaker tripped and won't reset.


My thoughts? Maybe it's bad wiring? Or maybe I've installed the breaker wrong? ... That would be strange, because they're not that hard to install. The outlet could be bad? Except that swapping in a different outlet or trying it with no outlet doesn't fix the problem. Wiring? ... Or maybe wiring?

(sigh) Never seen this before, and google turned up a lot of results that say "Check for water or something plugged in that's bad."

Any thoughts? I'm at wits end here.

Thanks,
Dan

I feel for you man. The new GFCI outlets are SO freaking sensitive. I had the same thing happen to me . Never did get to the bottom of it because I had electricians redo the whole house.

Nicked wire leading to an intermittent short? It's not uncommon to have wires hit by errant drywall screws.

Try a regular outlet for a few weeks and see if that trips the breaker. What did we do 20-30 years ago without them to protect us? I lived through it as a kid, and so did many of us. Yes, the GFIs do just go bad and are just too sensitive. Now they have those goddam lock out things that make it almost impossible to plug anything into it without using all my strength and scratching up all the new outlet with only using it a few times. I hate plugging a tool into a new outlet when the place is done. it always scratch the new outlets when the home owners come home. We jsut run a cord now. its better and cheaper then having to replace it with new.


Oh, you might have a cut wire on the clamp when the electrical guys pull the wire too hard. I don't think its your wires.

That was my instinct as well. :(

I may try running a normal breaker for a while. Or maybe a normal breaker with a gfci outlet? I don't know, I just really don't feel like re-running wires from a basement breaker panel to a second floor freshly-renovated bathroom. :(

Any other ideas?

Thanks,
Dan

I would try the regular outlet. You still have the breaker to protect the circuit.

Did you buy both breakers that went bad from the same place? If so, it could be that they got a bad batch of breakers.

Try a normal breaker with a GFI outlet at the end. The GFI outlet would be cheaper.

I have a question, as I'm not sure what's going on.

Do you have a circuit with one plain outlet and a GFCI breaker, or a circuit with a standard breaker and a GFCI outlet?

Is this outlet the only one on the circuit?

Assuming you are referring to a GFCI outlet on a standard breaker I have had the same problem.

Installed a new GFCI outlet for my sump pump, and everytime I would check on it, it would be tripped. Eventually it would not reset just like you describe. Replaced it with another brand and all has been well for about 6 months.

Try a different brand.

Apparently some products made in China are not up to spec, or so I have heard.

It is a GFCI breaker, a single wire (no junction boxes, lights, etc.) to a single receptacle. The receptacle is a normal $2 receptacle, not a GFCI, and it is the ONLY thing on the circuit.

That's the baffling part: It's literally just breaker-wire-outlet, with nothing else there to interfere. If it isn't the outlet (I've tried other outlets already), then it's either two bad breakers (possibly the same bad batch from the same Lowe's, purchased several months apart?) or something wrong with the interconnecting wiring.

Some other ideas that I'll try tomorrow morning:
1 - Pull the receptacle out of the circuit, remove the breaker, and check for even minute grounds between branches.
2 - Swap this GFCI breaker with another one of the GFCI breakers in the same panel. See if the problem follows the breaker or the circuit.
3 - Try a normal breaker (I do have spare 20A breakers) with a GFCI outlet (I'd have to go buy one). Or just a normal breaker with a normal outlet, for temporary.

If it rains hard here in Florida and the humidity goes up all our GFI's go off line. I guess they're going their job but it is inconvenient.

That would be my next step. Cheap, easy, definitive.

My first thought was also a short somewhere along the circuit. Or possibly interference from a more powerful circuit it's running near? Dunno what your interior wiring situation looks like...

Never had an issue with a GFCI but wait until your local code requires AFCI (arc fault receptacles).... ridiculous. Recent basement rehab and it was required. Total waste, PITA picky little bastards.

Install a regular breaker and a GFCI outlet? Cheaper?

JR

Those things go bad, and are sometimes bad out of the box, in my experience.

After reading through some of the stuff here, I was going to type the same thing.

I always fail to understand why people get so up tight about GFIs, now arc fault ? They are such PITA and sometimes is completely unnecessary.

I also had those experiences, and found out that GFCI was NEVER the fault.
They fill a function and are not "overly sensitive". Here in 230V/50Hz land GFCI is required to trip at 30mA earth current in order to be classed as "personal protection". Choosing the higher current rating will certainly make it less sensitive but also worthless as protection device as more than 30mA through body will likely kill you.

It's quite easy to troubleshoot. Break the circuit, remove the breaker and measure leads going FROM GFCI with ohm-meter. Resistance between earth, phase and null should be very high, almost infinite. If resistance in-between any of those leads is less than that, you either have a short (>10 Ohm) or a sneaky-leaker (10 - 100kOhm) due to water, a nail that went through the wire or something like that. First one is easy to fix, sneaky-leaker is dangerous one.

Common fault scenario is short between earth and null (or whatever you call it in 110V-istan) in outlet itself. It will not burn the fuse (as earth and null are shorted in the fuse box anyway) but it will trip the GFCI. Next most common scenario is "in between, not-quite the short" (the dangerous one), as it might electrocute you or start to burn without burning out the fuse. And this scenario is the one GFCI is there to protect you from.

GFI's suck.

end of message.



But then again, seem pretty robust under testing here.




GFCI test - YouTube

After inspection on my own house, they are all gone from my garage and all exterior plugs. The bath GFI plugs are there but not the kitchen.

I have one GFCI breaker feeding the whole house (3-phase 380/220V feed rated at 25 amps) ...GFCI is rated at 30mA which is "life injury protection"-class...what they calculate is highest current still giving you chance of survival.

It started tripping once. My first knee-jerk reaction was "#@!! GFCI is broken! I'll buy a new one". Which I did....same problem. Then it was "damn !@@@# GFCI, it's just a nuisance, I should bridge it". Fortunately, I came to my senses and took some time troubleshooting the leads with Ohm-meter. Of course, it wasn't the GFCI's fault...an 220V outlet was incorrectly installed during the kitchen remodel (wire too long) . Once plug was inserted, it shorted the pins between earth and neutral. Some of current went through earth and GFCI tripped. As it should. Without GFCI, I would never know this.
Outlet fixed = no more problems.

If GFCI trips, there is current flowing through protective earth lead. Alas, something is wrong. Find out what is wrong. Don't shoot the messenger.

The Youtube clip with guy drowning the radio into the sink is pure nonsense. He obviously doesn't understand how it works. As long as water in the sink is isolated from earth, it won't trip the GFCI no matter what he drowns in it as there will be no current flowing through earth.

But the moment he puts his hand in the water he better pray GFCI works and is rated low enough not to kill him.

^^^^ this. Especially since it has been replaced. There is some fault. Possibly intermittent - just to drive you crazy.

Ian

GFI's are needed?


Depends on year of home build, or permitted re-build, and codes at the time.


Codes get more and More anall all the time.


I believe present UBC and NEC NFPA79 code is any outlet, within 3 feet of in-house water source or sink/shower, or anything outdoor, or even in a garage/shop/out-building, needs a GFI


YMMV, IMHO, interpetation of code may apply.

Electricity is not to be messed with, nobody wants to be injured, burned, or house fire.

around here, all kitchen outlets now. it use to be 3'. arc fault through out (at least on my current job)

Yup. I had time to play with it this morning, so I went down to check the breaker. It reset just fine, and I've been using it with power tools all morning. If it works, I can't troubleshoot. Grr!

Yup, this is an outlet in a bathroom that'll be right next to the sink. It's a small bathroom, so it's pretty much within 3 feet of the shower and toilet, too. :-/ So it kind of has to work right, imho.

Ok, it finally tripped again, and wouldn't reset. I waited until Saturday morning (home during daylight) to swap the GFCI breaker for a normal breaker. Then I swapped the receptacle in the bathroom for a GFCI receptacle.

It's been working great for a couple of days now. I'll report back in a month. If it's still working, the big question is "why?"

Thanks,
Dan

If you have leakage between the breaker and the outlet then what you are seeing is expected. The ground fault receptacle won't see leakage upstream and it will be fine.

I would check from the panel with an ohmeter and a megger if necessary.

Expected? Ok, that's good. Or bad. Translating this to non-electrician: if there's a small ground between two phases somewhere in the line, it'll force a breaker to trip, but the outlet will be fine. ? Better question: if I have a ground on the line small enough that it doesn't trip anything, is that safe? Or is the fact that it trips a GFCI breaker an indication that the wiring is unsafe?

Ohmeter checked fine. I don't own a megger. :-/

I think you have leakage between the breaker box and the outlet.

If it were mine I would ignore it, unless it was practical to replace the wire.

Haha, it was practical to replace the wire about 3 months ago, before I hung the drywall. Murphy says that wiring problems don't happen until it's hard to replace the wires.

Thanks for the wisdom; I'll quietly ignore the problem. :)

Excellent post.

However, one thing to remember is:
An OHM meter (AKA handheld DVOM) has very delicate internal circuitry, and uses micro-amps through a wire to test resistance.
All powered by a small 3-9V battery power supply.

If there is a partial screw puncture (with 110V arcing), this may not "close" the short using a low voltage test, and may return a false negative of a short.

This reminds me of this thread

http://forums.pelicanparts.com/off-topic-discussions/625195-what-chances.html

A good quality meter will do 6 meg ohms and should be enough to give you an idea if you have a leak to ground. A decent megger will put 500 vdc on the circuit looking for leaks to ground or neutral.
Maybe to be safe try an arc fault breaker on that circuit and leave your gfi receptacle in play.
Just thinking that if you did have a small shunt to ground or neutral an arc fault breaker may keep your house from burning down.

An outlet GFCI is at the end of the chain. Local protection.
A breaker GFCI at the beginning and looks at the whole circuit.

Still not ruling out there could have been a fault with the outlet or the breaker, but it sounds like a wire has been punctured.
A normal circuit breaker may not be sensitive enough to trip the whole circuit, given a partial short.

Although this tool is expensive, it is cheaper then the alternative:
Amazon.com: Short / Open Circuit Finder and Circuit Tracer - Supersedes SHFFF300: Everything Else

Actually, it would be cheaper to re-route the wire, I think. It'll be some holes in the drywall, but I can do that. If there's a real risk of eventual house fire here, I don't think there's much option.

A very good plan. You know there is a problem & we ALL know that you don't mess with electricity. Replace the line.

Ian

Knowing this is looking through a different glass all...

But. I wish I had a GFCI that was more sensitive or just worked in college. My dorm room went up in flames at UConn my Junior year bc of a faulty GFCI.

I woke up at 2am in a lofted bunk choking down black smoke...not kuhl!