strange electrical AC problem (high/low voltage)
 

We are having some problems with the AC in our house and I wonder if
some of you can give me some idea what might be causing it.

We first noticed it to be lights flickering, and I thought it might be
some neighbor using some heavy equipment or something. Then a few days
ago while working on the computer I noticed my DSL modem and router
just power cycled for no reason.

So I went out and bought a UPS, and at night during 8-12pm, I can see
the UPS kicking in every now and then and goes back to AC power. So
something's wrong.

I took out my voltmeter and measured it, much to my surprise, one of
the AC lines is 90v and the other is 150v. In my room, one of the lamp
is very bright while the other one is dim.

After about 12pm, it sort of gone back to normal, both lines register ~120v.

Could a neighbor using some stupid equipment be causing this voltage
drop and increase? Has some equipment in the local electrical company
gone bad? The problem is not consistent, sometimes it happens and
sometimes it doesn't...

Thanks.

Raymond

Greetings,

The only way I know to get 150V where their should be 117V is if two 117V
circuits on different phases share a common neutral and the neutral has
somehow come disconnected or is lose. Before proceeding, please check for
this occurrence and let me know what you find. (You can probably check by
turning off circuits at the circuit breaker and watching the voltage.)

Hope this helps,
William

PS: Surprised your 150V bulb doesn't burn out.



wrote in message ...
We are having some problems with the AC in our house and I wonder if
some of you can give me some idea what might be causing it.

We first noticed it to be lights flickering, and I thought it might be
some neighbor using some heavy equipment or something. Then a few days
ago while working on the computer I noticed my DSL modem and router
just power cycled for no reason.

So I went out and bought a UPS, and at night during 8-12pm, I can see
the UPS kicking in every now and then and goes back to AC power. So
something's wrong.

I took out my voltmeter and measured it, much to my surprise, one of
the AC lines is 90v and the other is 150v. In my room, one of the lamp
is very bright while the other one is dim.

After about 12pm, it sort of gone back to normal, both lines register
~120v.

Could a neighbor using some stupid equipment be causing this voltage
drop and increase? Has some equipment in the local electrical company
gone bad? The problem is not consistent, sometimes it happens and
sometimes it doesn't...

Thanks.

Raymond

On Mon, 27 Dec 2004 23:04:24 +0000 (UTC), wrote:

We are having some problems with the AC in our house and I wonder if
some of you can give me some idea what might be causing it.

We first noticed it to be lights flickering, and I thought it might be
some neighbor using some heavy equipment or something. Then a few days
ago while working on the computer I noticed my DSL modem and router
just power cycled for no reason.

So I went out and bought a UPS, and at night during 8-12pm, I can see
the UPS kicking in every now and then and goes back to AC power. So
something's wrong.


You have a bad neutral somewhere. First of all, ask around to se if
your neighbors have the same problem. If so, contact the utility
asap; if not get an electrician to your house to check out your
breaker box. My parents just had this happen last week. They called
the electri company who blew it off until my parents found out the
neighbors were having the same problem and called them back.