OK...I am sitting here watching the afternoon movie, while a roast is cooking in the oven (electric) and the washing machine and dryer are both going. Everything in the house is electric. Suddenly the power goes off. Its off for several hours and then it comes back on and the lights are dim, the satalite on the tv says the transmission has been interrupted. Then it goes off again for another hour or two. When it comes on, the lights are REALLY dim. Then they get bright and the power stays up. Is this a rolling blackout; brownout or what? And how many times of it coming on and off at different strengths, are my light bulbs going to last? We can deal with it. Have a 40kw generator, just want to know WHAT I AM DEALING WITH and HOW to deal with it. By the way, the above scenario happens several times a year with our power.

-- Anonymous, July 02, 1999

Answers

This all depends on where you live, maybe, but here goes:

This happens where I live too.

the problem where I live is related to really old feeder lines (that come from the substations) and out of control trees that really need trimming.

If a tree limb falls on a feeder line, it knocks out the power to everything within the grid it serves downstream. sort of.

Well, that's the way it was explained to me after a survey of our town's feeder lines was done. I could see the boundries of "our" section and sure enough, across the street was served by the a different feeder line, which sort of explains why when our power is out, across the street, it is not.

Anyways-

When the power comes back on, everything in everybodies houses or businesses that WAS running now comes back on.

Also- things that WERE NOT running (like refrigerators or heating systems or well pumps or air conditioners) may have tried to cycle back on during the outage and are now waiting for power to return.

So when the power DOES come back on, it has to deal with:

the usual stuff, plus:

everyone's compressors, motors, whatever, coming back on ALL AT ONCE too.

Motors and Compressors all require 2-4 times their running power, for a moment, to start up.

I have a fridge in the basement that consumes 220 watts while it is running, but when it starts up, it consumes around 1200 watts for maybe 1/2 second.

Multiply this by all the other "cyclic" appliances driven by motors or compressors in your house and then add in all the other households or "customers" on the same feeder line.

You experience a sort of large-scale version of that "dimming" of the lights when the fridge kicks on or, in our case, when the washing machine starts up.

There is only (x) amount of power coming through the lines, but everyone is demanding (3x)or(4x) of power all of a sudden, just for a moment. It can take longer for this to settle out over the whole area than if it just happens "locally".

The danger of this is not for your light bulbs,(they actually prefer slowly coming on and off rather than an abrupt surge of 110v), but for the motor-driven appliances.

If the low voltage situation (temporary brownout) does not settle out within maybe 10-20 seconds, your motors will begin to overheat. this won't immediately cause damage to your appliances, but depending on the length of time and how often it happens, it WILL cause the life- span of the motor to deteriorate.

Whenever the power goes off around here, it is off for at least an hour. If I'm home, I go to the breaker box and turn off fridges, washer/dryer (if they were running) electronics, etc.

When the power comes back on and seems stable, I throw the breakers back on, one at a time with a 5 second pause between each one.

Well. that's how I deal with it. I'm sure someone else has another way.

Incidently, since you HAVE a generator, it seems like a power outage would be a good time to cycle it and USE it.

Since I'm guessing that you are in a somewhat rural area, if you rely solely on your genny, you may never realize if and when the power DOES come back on. so maybe install a small lamp that is not fed by the generator that you could use as an indicator of when the "service" is back on?

But I don't know how you have your generator hooked up to the house, transfer switch? run extension cords? what?

-- Anonymous, July 02, 1999

gnerator is wired into the house box and yes has transfer switch. Its manual and not automatic as we don't want it coming on every time the power goes off. We figure on using about 2 hrs a day if grid is down. We will be pumping water for a lot of neighbors to fill their jugs. Thanks for the info...Taz

-- Anonymous, July 05, 1999