Partial power outage?

[Duane Bozarth]

One side of 240 supply failed...so what was on that side through your distribution panel also failed.

[Frogleg]

Power went out here in a very odd way the other day, and I can't get through to power co. for an explanation. Flourescent lights in one room flickered, dimmed, and went out. Radio lost volume and then went out. Computer stayed on (with CRT monitor) quite happily until I shut it down. 'Fridge stayed on. Some incandescent lights would switch on normally; others wouldn't. Little clock radio quit; light plugged into same outlet worked. Flourescent in another room remained on.

Electric co. said problem was a neighborhood transformer, and a couple of blocks were affected, not just my house. So what kind of a failure is it when some electricity works and some doesn't? I've always thought of it as an on/off situation.

[toller]

A few years ago my office lost 1/3rd of the circuits. Turns out a branch had fallen on one wire of the 3 phase feeding my building. I was urged to immediately unplug anything that used more than 120 because it might get insufficient voltage.

Obviously you don't have 3 phase, but I expect something happened to the transformer so you only got one leg of the 240v.

[Colbyt]

The simple explanation is that power is supplied to homes with 2 hot wires and one neutral wire. Half (an over-simplification) of the stuff in your home uses one of the hots and the other half uses the other. Stoves, electric heat and AC units use both hots.

If one leg (one of the hots) is not working some of your stuff will work and the rest of it won't.

Colbyt

[Mike Dobony]

Yup! My f-i-l had that happen. When he turned on the stove, everything worked. Turned out the feed to his outside box was too short and the freezing pulled it out of the breaker. The electric company had to come in and put in a longer feed line.

[Scott Townsend]

I like to call them Brown Outs. (-;

[JohnR66]

And... Any 240 volt devices that are energized would "back feed" the open leg. Due to loads on the open leg, the voltage would be low, but present. Be sure to shut off any motorized or electronic appliances that could become damaged. John

[CL (dnoyeB) Gilbert]

Yes, thats the term commonly used around here. Brown out. Its dangerous for some appliances, mostly motors/compressors. Unplug the refridgerator.

Yes this is transformer problem. The beauty of the setup is you can buron out one of the phases of a transformer, and it will keep doing its job. It just has less power to give out. Unfortunately if you burn a few out, and the transformer gets loaded, the voltage will start to drop then.

[Frogleg]

Thanks to all for replies. And please pray for 'fridge. Thought it was miraculous that it kept working. :-(