The case of the flickering bulb
Mar. 31st, 2012 09:28 pm![[personal profile]](https://www.dreamwidth.org/img/silk/identity/user.png){kind=small}
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fandom_jointsI replaced a ceiling-mounted light fixture today, but it has me worried.
It's wired as though it was controlled from 2 switches, but there is only one switch for it. There has been only one switch for it for at least the last 30 years. God knows what was there before that. (The house was built around the 1930s, and uses cloth-covered wire. The old wire connections are soldered together, then encased in something like bakelite, the wrapped in copious cloth-based tape.) I installed the new light fixture, rewrapped the wires, was exceedingly careful to cover any potentially exposed wires. It works fine.
But when the switch is off, there's still some power to the light -- not enough to light an incandescent, but enough to make a compact fluorescent blink.
This is not, near as I can tell, anything that I could have done when working on the fixture. The circuit should be open and there should be no current flowing when the switch is off. But that's clearly not the case.
What the heck? I have no clue what's going on there, but it's making me twitchy. I have possibly paranoid fears of an intermittent short someplace in the walls that could burn down the house.
Any clues?
It's wired as though it was controlled from 2 switches, but there is only one switch for it. There has been only one switch for it for at least the last 30 years. God knows what was there before that. (The house was built around the 1930s, and uses cloth-covered wire. The old wire connections are soldered together, then encased in something like bakelite, the wrapped in copious cloth-based tape.) I installed the new light fixture, rewrapped the wires, was exceedingly careful to cover any potentially exposed wires. It works fine.
But when the switch is off, there's still some power to the light -- not enough to light an incandescent, but enough to make a compact fluorescent blink.
This is not, near as I can tell, anything that I could have done when working on the fixture. The circuit should be open and there should be no current flowing when the switch is off. But that's clearly not the case.
What the heck? I have no clue what's going on there, but it's making me twitchy. I have possibly paranoid fears of an intermittent short someplace in the walls that could burn down the house.
Any clues?
no subject
Date: 2012-04-01 07:15 pm (UTC)(The two things you don't fuck around with doing more than the basics yourself: electricity and plumbing.)
Seriously, though: an electrician will have tools to tell him/her how much current is going through the wires and where any breaks or shorts or problems happen. This is the kind of problem you can't diagnose easily with stuff at home and when you're dealing with old wiring like this, it's best to have somebody who knows their shit look at it.
no subject
Date: 2012-04-02 04:05 pm (UTC)But I also consulted familial memory (the family acquired this house in something like 1961), and it is a known problem stretching back to when the AM radio station built a higher-power transmitter down the valley.
Some of the power lines are unshielded and act as antenna. It was apparently a big deal back in the late 1970s when the entryway light (in the same corner of the house) was installed, and then reinstalled, and then the subject of a great deal of swearing, and then provided with overkill shielding and an admonition to not mess with it unless one is willing to rewire the entire circuit. I had a similar hassle with interference on the phone wires when we started using a modem.
We're still going to have an electrician check it when we have him run new circuits for AC units. I still want to know what happened to the second switch. The existing switch is in a stupid place.
no subject
Date: 2012-04-02 11:27 pm (UTC)