Electricity = juice ≈ OJ

May 23, 2007 10:35 PM

What could cause electricity to go out sporadically?

In the apartment where I live the electricity has been going out to half of the apartment. It is an older house that the breakers have been converted to modern breakers, but I am not sure about the rest of the wiring. I am sub-metered off the main meter.

Electricity has been going out in half of the my apartment periodically - there is no schedule or anything common to the outage that I can recognize. The outages last anywhere from 10 minutes to up to a few hours.

And then the electricity comes on again by itself. I have checked the breakers each time and none of the breakers have tripped. I checked the outside breakers and the inside breakers. Nothing has tripped at all. So it can't be a load problem right? Can breakers just reset themselves? Is there a loose wire somewhere?

posted by bigmusic to home & garden (10 comments total)

Sounds like one of the halves of your center tapped transformer is going. You'll have to call your power company.

Electricity comes from the plant in three "phases" which are 120 degrees out of sync. Tap across any two phases and you get ~240V service (washing machine, dryer, stove, blower, etc). To get ~120V (or half 240), which is what most of your appliances run on, then just tap into the center of the transformer coil. If the windings are failing on one side you would lose half your 120V service and all your 240V.
posted by sbutler at 10:41 PM on May 23, 2007

that's a simplified explanation, btw. I just know paulsc is going to jump in with a better one.
posted by sbutler at 10:45 PM on May 23, 2007

Corrosion in the connection where the the power lines enter your building. There are two wires going in and half the circuits are powered by one or the other.

Wind or birds sitting on the line can cause breakage.

Call your electricity company.
posted by MonkeySaltedNuts at 10:45 PM on May 23, 2007

Er... well, its anecdotal at best but I was once in a building where the neighbor on the other side of the wall "shared" an outlet with our breaker box. He had his computer and other stuff plugged in (he had figured out before we moved in that he didn't pay for that outlet.) Unfortunately for him that circuit in our breaker box was in our kitchen where we ran our microwave, a window air conditioner, occasionally the vacuum cleaner, and a few other things... so we were constantly tripping the breaker. After a few discussions he agreed not to use that outlet. (This was after a few accidental and some intentional flipping of the breaker to fuck with him.)

So, its a long shot, but perhaps you're sharing a breaker with someone else in your building and they are more quick to flip it back on than you are?!??
posted by wfrgms at 10:53 PM on May 23, 2007

Corrosion in the connection where the the power lines enter your building.

Seconding this. Lived in a farmhouse years ago with upgraded electric, but the upgrade was apparently done in the 70s when aluminum wiring was the norm. We had sporadic outages, bad enough that we had to put all of our computers on battery backup and got used to resetting the clocks.

Finally, after much rigamarole, got the landlord to do some investigating and he found the connection to the house had corroded to a thing point -- and you could actually hear it arcing when the power was on. Power company fixed it, and the troubles went away.
posted by davejay at 11:09 PM on May 23, 2007

thin point. bluh
posted by davejay at 11:09 PM on May 23, 2007

"... I just know paulsc is going to jump in with a better one."
posted by sbutler at 1:45 AM on May 24

Nope. You're doin' fine, as far as practical transformer descriptions go, sbutler.

I would suggest, however, that if the service to your building is underground, that it may well be your underground cables that are going, rather than your transformer. A lot of underground cable laid in the late 80s and early 90s when buried utilities became really popular has reached the end of its service life, and has begun experiencing insulation failures, and conductor corrison of great enough magnitude to cause power companies to rewire whole areas of cities, and residential sub-divisions.

I had this problem in my sub-division, in Northern Florida, on about bigmusic's same latitude, last year. Not that latitude is the issue, but a lot of southern utilities got the bug for buried lines in the same era, when the second generation underground cabling systems were really being pushed by vendors, and loved by real estate developers.
posted by paulsc at 11:11 PM on May 23, 2007

Has there been a lot of rain is your area lately? Are your utility lines underground?... Could be short-circuiting... Seconding the people who advised you to call your utility company.
posted by amyms at 11:26 PM on May 23, 2007

Corrosion in the connection where the the power lines enter your building.

Thirding this. It happened to my house. We called hydro, they came out, cleaned the wired, put on new connectors, no more power outages.
posted by GuyZero at 7:47 AM on May 24, 2007

We had the same problem last summer. Lots of rain, half the power out. It was the utility's fault, and they fixed it.
posted by MrMoonPie at 8:08 AM on May 24, 2007