Electric outlets mystery

[Stephen Tashiro]

Friends have the following situation. In investigating why a number of electric outlets seemed to go bad at their house, they found that a GFI receptacle in a bathroom disables many other receptacles throughout the house if the GFI is tripped. The GFI receptacle seems to be faulty, it is loose in the box and difficult to reset. Sometimes it must be jiggled before it can be reset. Naturally, they tried turning off the current to the GFI receptacle in order to replace it.

In the same bathroom, there is another receptacle with a night light on it. When they flipped breakers to turn off current to GFI receptacle, they noticed that no single breaker will turn off the current to the receptacle with the night light. (When the GFI receptacle is tripped, it does turn off current to the night light receptacle and many others.) Since the GFI has been reset and all the other outlets now work my friends paused their lengthy investigation to take care of other things in life and think about the problem .

The only explanation I see is that some mis-wiring that has connected the circuits from two (or more) breakers together. I suggest flipping pairs of breakers to see if a pair of them will turn off the current to the night light receptacle. That could reveal which circuits are connected. Is that a good first step?

[John Terefenko]

Yes you probably have 2 seperate circuits which happen to be on the same phase supplying the night light. If that is the case then it is probably backfeeding the GFCI also so be careful of that. What happens when the GFCI trip it takes out the neutral wire which is why the nightlight goes off but there is still power at the outlet from a stray circuit. This needs to be looked into. What you wanted was the hot wire that supplies the GFCI to also supply the outlet with light but you want to pull that feed from the supply side of the GFCI and not the load side. Same with neutral. Will require a splice. You need to find the off circuit and safe it off in the nightlight box or trace it back to where it is tied in. It could be right in that box and someone wanted to use the box as a junction point to carry a circuit on to other outlets. Older code allowed you to use a 3 wire to supply 2 circuits with one neutral and I bet that is what is happening but what they did wrong was put both circuits on the same phase and if that is the case than that neutral is over rated amp wise. You could have a potential fire situation. The other scenario is two circuits were brought into box and someone tied all blacks together and all whites together and did not separate the circuits. These are guesses and until you look in both boxes you will not know for sure and then you still need some knowledge as to what to look for. and a meter. I would have an electrician look at it because as I said you can have an overload problem and not know it.

[Jim Koepke]

These are guesses and until you look in both boxes you will not know for sure and then you still need some knowledge as to what to look for. and a meter. I would have an electrician look at it because as I said you can have an overload problem and not know it.

All we can do is make guesses. John is right in suggesting you have a qualified person look at this if you do not have an electrical background.

My guess Stephen is you do not have such a background.

GFI outlets are able to protect multiple outlets. Your description seems to indicate the GFI outlet may have been installed without being wired to a breaker.

Most breaker boxes have a panel that can be removed to allow access to the wiring inside. This would reveal if wiring was installed without the benefit of a breaker.

Other options would depend on what changes have been made to your home since it was built. You may have a second breaker box or fuse panel.

jtk

[Bruce Wrenn]

Back in the seventies, GFCI breakers were EXPENSIVE and finicky. GFCI recpt.were much cheaper, though definitely not free. The code required the bathroom recpt. closest to the sink to be on a GFCI, plus garage / carport and any outside recpt. By having recpt. in bathroom, it was easy to reset, no walking to panel box, while wrapped in a towel. Since the total load on the circuit was low, all could be on same circuit. Remember this was BEFORE curling irons, hot rollers, and blow dryers. Now each bathroom has to be on it's own circuit.

[John K Jordan]

...no single breaker will turn off the current to the receptacle with the night light.

Someone wired my sister's house like that. I turned off one lighting circuit to work on it and discovered it was still hot (always check). Someone had wired a cable fed by a second breaker into a light switch in a stairwell.

[Lee Schierer]

I got tired of guessing which receptacles were powered by which breakers in my house and when I help my kids with their houses. I purchased a Klein ET 300 circuit tracer for ~$30. It has a transmitter that plugs into a receptacle and a receiver that scans your circuit breakers and beeps as you pass over the breaker with the transmitter in the circuit. There is a pilot light on the transmitter that goes out when power is shut off.
436952
With a screw in light socket to plug adapter you can also trace lighting circuits back to the proper breaker. It saves a lot of time.
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When I remodeled our bathroom I noted that there were two outlets one high by the light for the vanity mirror and the other in the normal position near the floor. They were both on different circuits, neither were ground fault protected. Both are protected now with separate GFIC's

I also use an outlet tester all the time when checking wiring of receptacles.
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[Jim Koepke]

I also use an outlet tester all the time when checking wiring of receptacles.
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This is a good investment just for the peace of mind of knowing an outlet is properly wired.

And as John posted, ALWAYS CHECK a circuit to ensure it is not powered.

jtk

[Bruce King]

If anyone has GFI receptacles with the red and black buttons on them that are older than about 1995 they are very hazardous. During my 13 years inspecting houses it was a rare event that these would actually trip off with a ground fault.
The most common ground fault and the reason they invented these devices is current going through your body. All right GFI receptacles need testing every month. Many other types go bad too and won’t trip. If one is hard to reset it must be replaced. If it still trips you have current leakage somewhere. The GFI circuit breakers are more reliable but also fail at times. Check all after a lightning storm too.

[Rick Potter]

This is probably off base, but are you sure the night lite does not have a backup battery? I have one that does.

[Stephen Tashiro]

I purchased a Klein ET 300 circuit tracer for ~$30.


Some Amazon reviews of that tool say the automatic-on feature is too sensitive. Is the ET 310 model is an improvement on the ET 300?

[Stephen Tashiro]

This is probably off base, but are you sure the night lite does not have a backup battery? I have one that does.


You're not off base - I asked the same question of my friends. They said no.

[Stephen Tashiro]

. Older code allowed you to use a 3 wire to supply 2 circuits with one neutral

I'm glad you told us about that possibility!

[Thomas McCurnin]

Arc Faults do not rely on the neutral bus bar to trip. They are hard wired with a neutral that goes exclusively to that protected circuit.

I suspect that the other circuits improperly share that neutral. It’s a common service panel mistake.

My assumption is that the other circuits have the same phase. Are they all even? Or all odd?

[Lee Schierer]

Some Amazon reviews of that tool say the automatic-on feature is too sensitive. Is the ET 310 model is an improvement on the ET 300?

I have to push a button on my ET300 to turn it on. The button is very sensitive so I made a holster to carry the receiver in so it doesn't get accidentally turned on.

[Charlie Velasquez]

........
Older code allowed you to use a 3 wire to supply 2 circuits with one neutral and I bet that is what is happening but what they did wrong was put both circuits on the same phase ........

...... I would have an electrician look at it because as I said you can have an overload problem and not know it.

Sound advice.

I believe multiwire branch circuits are still code compliant.

[John Terefenko]

Sound advice.

I believe multiwire branch circuits are still code compliant.
Not to my knowledge. All need own neutral. I know it is that way in commercial work.

[Charlie Velasquez]

Not to my knowledge. All need own neutral. I know it is that way in commercial work.

Wrt multiwire branch circuits, I believe 210.4 covers its use.
I think in at least one instance, a detached garage, if one wants to run power to it without running a sub panel, one could argue a mwbc is the only code compliant way to do it.

edit: this exact discussion is taking place on Mike Holt’s forum right now.

[Tom M King]

Shared neutrals were common practice, for decades, before Arc Fault breakers were required, and they found out that wasn't a good recipe.

I got my license in 1975, but only did the electrical work in the new houses, that I built one of for 33 years. I never felt comfortable with shared neutrals, so didn't use them. My houses built in the '70's, through the '90's, may have been some of the few built without shared neutrals. I was building spec houses, under no boss, so no pressure for fast, and cheap.