Input needed from residential electrical guru

[MiCarl]

Last fall we bought a new to us home.

Today wife informed me that the light in the laundry room was out. When I opened the fixture it had 2 bulbs, one a fried incandescent and what I think is an early LED that had noticeably loose parts in its globe.

I stuck a pair of 100watt equivalent CFL lamps in the fixture because that's what we had on hand. The CFLs work just fine with the switch turned on.

When the switch is off they blink in about the bottom fifth of the tube. The blinking is random and one is fairly white while the other is orange (same lamps). They don't necessarily blink together. With the globe on it's like watching a thunderstorm in the distance.

I've used CFLs before but never seen anything like this.

Any suggestions what to look for?

[Barnyard]

You might want to read this thread. Some of the replies may apply to the cause of your problem.

My electrician found a shorted outlet that was on the same circuit as the lights. Hopefully, your problem is not as bad. You may have loose wires inside the fixture.

[tst]

check the switch

[Eugene]

check the switch

Yes. Do check.

Another possibility is that the switch is wired on the neutral wire instead of the hot wire. Or mis-wired at the fuse box/breaker panel.

[SamsFarm]

Do you have a good meter?

Make sure it is on ac setting (~)
With the light off check the voltage from common to neutral, then neutral to ground, and from common to ground!

What are your readings?

Is your light hooked to a 3-way switch(s)?

[MiCarl]

Not on a 3 way switch.

Previously saw the topic about Barnyard's problem.

I can see how a loose wire might cause it to flicker when on, but not when it's off.

One more piece of information: When I installed the first lamp the switch was in the on position and the lamp flickered just as the threads touched. At the time I thought it odd because it should have been well clear of the center contact. So my current thinking is maybe It's got something going on with what should be the neutral...... I hope I'm wrong because that could come from anywhere in the house.

Rainy day today so I need an inside project. I'll break out the meter and try to find what's going on...

Thanks for your input.

[MiCarl]

Update:

I swear Homer was having a bad day when he wired this house (after this project he was fired and took a position at the Springfield Nuclear Plant).

I started by pulling the switch plate in the laundry room. I saw the switch had one black wire and one white wire attached, and no other wire (other than the ground) in the box. No problem. I pulled the fixture expecting to see two pair (plus grounds) with the blacks connected, white to the fixture and white from the switch wrapped in black tape and connected to black on the fixture. No Dice. Just the one black/white/ground set. Continuity from the white at the switch to the black in the fixture.

Went on a hunt for the color change in the other boxes on the circuit. Nothing there. Headed to the attic expecting to find a junction box. Nope. Wire from fixture comes to the garage wall and drops with the garage wiring (a different circuit). So I expected to find a junction crammed into the garage switch box. Nope, not there.

Headed to the basement. Sure enough there is a wire that comes through the floor below the laundry room switch. Hot Damn! Get to looking and someone has tied into this to add the wired smoke detectors. All that wiring looks OK.

In the process I find that unplugging all the smoke detectors eliminates the flickering when the laundry room light is off and the laundry light works normally. Looking further I see that with the smoke detectors plugged in their power lights go off when the laundry room light is switched on.

So apparently the smoke detectors are getting their neutral back through the laundry room hot. The connections where the detectors are wired in seem right. I still haven't located the path of the laundry room switched hot and where the color changes.

I suspect I have a bad neutral connection somewhere. Every "original" electrical connection in this house has straight wires stuck into a nut and the nut tightened. The "new" connections for the smoke detectors are twisted together before the nuts are put on which is what I'm used to seeing.

That's what I accomplished this afternoon, nothing!

I think my next step is to start opening things up and re-doing the original connections. I expect I'll find a white wire floating loose somewhere.

[tst]

also check your grounds

[Eugene]

I expect I'll find a white wire floating loose somewhere.

Wire nuts tight. Slight tug on each wire at the wire nuts. Looking for loose wire.

[MiCarl]

Problem is fixed.

After my previous write up laying in bed thinking about it. Sure seemed symptomatic of the smoke detectors using the switched hot for the laundry light as their neutral. I thought I'd tested for that but thinking about the number of wires in the boxes it seemed there couldn't be a neutral in the boxes.

Went back this morning and checked. What appeared to be the neutral in the boxes and for the smoke detector was the switched hot for the laundry lights. I ran another feed for the smoke detectors and properly marked the switched hot in the basement boxes.

Not sure how I missed that two days ago. I guess I was focused on where that switched hot went from white to black (which I never found) and was tired and frustrated after a day trying to chase that wire.

I still have no idea why the original electrician ran the wiring from the switch to the light down to the basement and back up a different wall rather than going straight to the light which is literally directly above the switch.

Thanks again for your input.

[Don McCombs]

Glad you got it fixed.

[Eugene]

Yup. Glad you got it fixed.

The hardest thing about working on residential wiring is figuring out what the previous electrician did.

[SamsFarm]

I still have no idea why the original electrician ran the wiring from the switch to the light down to the basement and back up a different wall rather than going straight to the light which is literally directly above the switch.

The person that did he wiring had extra wire and forgot their wire cutters that day!



I bought me one of those Fluke voltage pens for like 2 bucks from my one neighbor at her garage sale years ago.

It has been one of the first tools I grab for a home /shop electrical job ever since!