OT Electrical Conundrum

[DonkeyHody]

Don't try to send me off to rec.homerepairs; I don't know anybody over there. I've seen enough good electrical advice here to know somebody will have the answer.

Yesterday I noticed that neither of the bathroom lights worked. Knowing that the lights are on the same circuit as my wife's hair dryer (because the lights dim a little when she fires it up), I deduced that the GFCI breaker had probably tripped. It didn't look tripped, but I flipped it back and forth to be sure.

Still no lights.

I checked the hair dryer receptacle to be sure; no power there either.

Back out to the breaker box with my handy-dandy digital electric tester. The wire lug on the suspect GFCI breaker reads 121.6 volts to the neutral/ground buss.

But still no lights.

I snapped the breaker out of the panel and looked for corrosion or evidence of arcing. Found none. Snapped it back in, but forgot to check the results before moving on to the next step. Left the breaker off.

One of the receptacles has gotten old and tired from plugging/unplugging and doesn't grab the prongs good anymore. It seems to be closer to the panel box than anything else, so I pull that receptacle out of the box to check the feed wire for voltage. Flipped the breaker on and . . . voila! Voltage . . .and lights . . . and hair dryer! Everything works!

Since the receptacle was old and tired and I already had it out of the box, I replaced it and two other elderly and infirm receptacles on the same circuit. Everything works.

Bragged to SWMBO about how much I saved by not calling an electrician. She was unimpressed. Expected no less. Said that's why she keeps me around.

But I don't know what the problem was!

I'm about to go out of town for 2 months, and I know she's gonna flip the switch and find the bathroom stays dark. Then I'll have to pay a repairman for the first time in about 10 years because I won't be there to troubleshoot it.

When our kids were young, SWMBO used to tell them that Dad can fix anything but a broken heart. My reputation is on the line.

What was wrong?

DonkeyHody "In theory, theory and practice should be the same. But in practice, they're not."

[Charlie M. 1958]

I'm no electrician, but it sounds like a bad connection in that receptacle was keeping the juice from making the rest of the circuit. This would make sense since it was the closes one to the box. Pulling it out of the wall jiggled things enough to work temporarily, and replacing it was the permanent solution.

[Swingman]

Simply put, and from your description, most likely just a bad connection in the first receptacle in the run.

[DonkeyHody]

That was my guess too, but I'm unsure about the connection between the breaker and the hot buss. I thought maybe the connection was good enough to show up on the meter, but not good enough to carry the amps needed. However, if the connection there were loose, the load on the circuit would bleed off the voltage downstream of the loose connection, and I wouldn't have 120+ volts on the breaker's wire lug, right??

DonkeyHody

[Swingman]

"DonkeyHody"

the

I doubt that was/is the problem ... but then again, I hire electrical contractors for everything but my own shop needs, so take my advice for what it cost you.

[Doug Miller]

Bad connection on the first receptacle. When you pulled it out to check it, you jogged it around enough to make contact. The other outlets were fed through that one.

I wouldn't be a bit surprised if the connections at that receptacle were "backstabbed" (using push-in terminals on the back side). If so, you just found out why backstabbed connections aren't a real good thing. I hope you used the screw terminals when you installed the new ones.

[Nova]

Breaker switched off...

... breaker switched on.

The circuit breaker was most likely tripped. On a variety of different brands of breakers its very difficult to tell if they're tripped by visual inspection.

[Doug Miller]

Don't think so. He said near the beginning of his post:

" It didn't look tripped, but I flipped it back and forth to be sure."

[Nova]

I read that to mean the GFCI.

I did notice that the OP said he checked the voltage at the wire lug of the breaker and read 120V to ground. I've be known to measure voltage on the wrong breaker occasionally. :-(

[Markem]

Was the device use to connect the wires in the run. If so that is what was wrong, pigtailing to the device ensures voltage beyond a bad plug (device).

Mark (sixoneeight) = 618

[Doug Miller]

I read that to mean the "GFCI breaker" that the OP said he checked and flipped.

The relevant paragraph in full: "Yesterday I noticed that neither of the bathroom lights worked. Knowing that the lights are on the same circuit as my wife's hair dryer (because the lights dim a little when she fires it up), I deduced that the GFCI breaker had probably tripped. It didn't look tripped, but I flipped it back and forth to be sure."

Two specific references in the original post to a "GFCI breaker" mean either that the GFCI and the breaker are one and the same, or that the OP is using terminology incorrectly.

I'm gonna go with the former.

I've *never* done anything *that* dumb. Not often, anyway.

[Lew Hodgett]

My guess is that the old receptacles were of the "strip & stuff" residential grade.

Basically, you strip the insulation of the solid conductor wire, then stuff the bare wire in the hole in the back of the receptacle.

The wire is retained in the receptacle by using the Chinese finger puzzle technique on a spring. Basically, a one way clamp.

If the receptacle carries enough load for a long enough period of time, the spring gets tired.

Replacing the receptacles with a better grade that has side wired screw terminals should solve the problem.

One other possibility I really don't want to think about.

What is the age of the home?

Any chance we you have aluminum wiring?

Lew

[Pete C.]

Digital meters have very high input impedance and are notorious for showing "phantom" voltages on circuits that are dead, but adjacent to live ones. The solenoid "Wiggy" testers are popular since they don't have this trait.

BTW, not that you've found one loose connection at a failing receptacle, buy yourself a couple boxes of spec grade receptacles and perhaps switches as well and spend a weekend replacing the old ones and checking and tightening all the connections. Time well spent in improving safety. That bad connection was likely getting pretty warm every time the hair dryer was in use before it finally failed.

Pete C.

[DonkeyHody]

Just to clarify a few points . . .

1. I'm talking about a Sqare D 15 amp GVCI circuit breaker. The GFCI is provided at the breaker, not on a receptacle.

1. I checked the voltage at the wire lug on the breaker several times and flipped the breaker on and off to verify that the voltage drops to zero when the breaker is off. By the way, the digital tester apparently doesn't carry enough current to trip the GFCI when I tested the voltage from wire lug to ground.

2. All the wiring in the house is copper. This circuit happens to be

14 gauge copper. The house was built in 1976 with 14 gauge wire and a single GFCI breaker serving lights and receptacles in two bathrooms, two receptacles in the living room, two kitchen counter receptacles by the sink and two outside receptacles. Several years ago I split the circuit, added a second 20 Amp GFCI breaker, and ran 12 gauge copper to the OTHER bathroom because a hair dryer in either bathroom dimmed the lights so much, and two at once would trip the breaker (DUH). Without so many loads on the wire, the 20 amp circuit doesn't dim at all with the hair dryer, and the 15 amp dims just enough to notice if you're watching it.

My main question was whether the most likely culprit was the old receptacle with stab-in connectors or a loose connection at the breaker. I think you've convinced me it was probably the receptacle. Thanks for all the replies.

DonkeyHody "Every man is my superior in that I can learn from him."

[Lew Hodgett]

Define "spec grade".

Every wiring device on the planet is "spec grade", just depends on what is defined as "spec".

Lew

[Joe]

This the most significant post in this thread. Good electrical workmanship requires receptacles in series to be pigtailed. Most building codes require it. And sadly, way too few DIY'ers ever do it. My pair of pennies.

Joe

[Pete C.]

I don't need to define it, the electrical manufacturers already have and "spec grade" is stamped right into the devices. HD and Lowe's tend to label the bins "commercial grade" or "industrial grade", but the devices are marked "spec grade". They are vastly better than the $0.50 pieces of junk that I'm surprised are even approved for use.

Pete C.

[DonkeyHody]

See, I learn something new every day. I didn't know wiring in series was a substandard way of doing it. Most every receptacle I ever pull out of a box uses the receptacle itself to transfer the power down the line. And most of them have the wires stabbed in the back instead of screwed to the side. I can see the advantages of pigtails, and I'll do it that way from now on. I don't think I'll go yanking my receptacles out to retrofit though. Thanks for the tip.

DonkeyHody "Every man is my superior in that I can learn from him."

[Markem]

Wire nuts with pigtails with a machine crimped lug. Fast efficent and now when the problem reoccurs (and it will) having some around will make for quick repairs.

Mark (sixoneeight) = 618

[Lew Hodgett]

You're right, we did it and so did all the competitors.

Was and still is a good marketing gimmick.

Lew