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Q: Stabilizing a Home Power Circuit ( No Answer,   1 Comment )
Subject: Stabilizing a Home Power Circuit
Category: Family and Home > Home
Asked by: ozar-ga
List Price: $5.00
Posted: 14 Aug 2006 14:15 PDT
Expires: 13 Sep 2006 14:15 PDT
Question ID: 755952
I live in a fairly modern cookie cutter house built in the late 1990s
in the state of Texas.

From the first week that I moved into my newly constructed house, I
noticed that the startup of the central air conditioning (AC) unit
would occasionally disrupt the power in one of our bedrooms.  Lights
would dim (in that room) and our computers would reset.  It didn't
happen often, but it happened enough so that we purchased two
different UPSes (Uninterruptible Power Supplies) from two different
manufacturers to cover the more power sensitive equipment in the room.
 Prior to the purchase of the UPSes, the power would only be disrupted
occasionally -- As in not on every central AC unit startup, but ONLY
because of the central AC unit starting up.  I would estimate that the
disruptions happened no more than 4 times daily.  In all cases, the
circuit breaker itself would NEVER actually trip in such a way
requiring a physical reset of the breaker switch.

To the best of my admittedly limited novice knowledge, the central AC
unit is NOT on the same circuit breaker as the room in which the
linked power disruptions are occurring.

After the UPSes were purchased and installed, the power disruptions
were manageable until it became necessary to install a window AC unit
in the bedroom with the computer equipment and UPSes (the problem
room).  Now, every time the window AC unit compressor starts up, the
bedroom lights momentarily dim and I can audibly hear the switches in
the UPSes activate momentarily.  This happens at least once every 15
to 45 minutes when the window AC unit decides that it is time to turn
the compressor on again.  Again, the power disruption does NOT trip
the circuit breaker in such a way requiring a physical reset of the

I want to stabilize the power circuit in the problem room in such a
way that the lights don't dim and the UPSes are not forced to
continuously kick in throughout the day.  I am not comfortable with
the frequency of which we are causing the UPSes to kick in on a daily
basis (minimum of 48 times a day), and it would be nice to not have
the room lights dim when we don't want them too.

Unacceptable non-qualifying answers include:  removing the window AC
unit and removing any of the other electrical devices operating in the
problem room, planting a tree and learning to live with less, or any
other hippie crap.  ;-)

This strikes me as a fairly low-tech problem that I just don?t have
the experience to figure out by myself, and I don't think it should
involve any highly complex and overly expensive solutions.

On the advice of a friend, I recently changed the 15 AMP double pole
breaker the circuit was on to a 30 AMP double pole breaker.  There has
been no change in the situation.  So, I can clearly conclude that in
part or whole, changing the circuit breaker to one with higher
tolerances is not the final answer.

Here is a list of the major electronic items drawing power in the
problem room:  3 computers, 1 high end 5 channel speaker system, 1
printer, 1 networking switch, 1 cable modem, 2 UPSes, 1 big screen TV,
1 DVR, and 1 game console system.

Once again, I am a novice with fairly limited experience.  Please
explain things accordingly.

I am looking to (1) Understand the problem I am dealing with,
specifically why the circuit breaker does not trip but the UPSes do &
(2) Find a solution to put in place myself that does not require me to
rewire the whole house or hire an expensive contractor to install some
over priced system that my children will still be paying for long
after I am dead and buried.

Thank you for reading my question.
There is no answer at this time.

Subject: Re: Stabilizing a Home Power Circuit
From: neilzero-ga on 14 Aug 2006 16:47 PDT
Aluminum lead in wires to your house may be the cause. Since two or
more circuits are affected, my guess is the trouble is between the
main circuit breaker box and the power company, especially if you
notice lights dimming in other parts of the house. During the 1/10th
second surge drawn by the air conditioners, the line voltage likely
drops from 120 volts to about 80 volts, which shut down your
computers, before you added the two UPS. Some voltage drop is normal
when current surges occur, but it should not fall below 100 volts. If
my theory is correct, you should see some light diming all over the
house, when appliences with big motors turn on, such as washing
machines, clothes dryers, automatic dish washers, refrigerators, deep
freeze and possibly hair dryers, blenders, microwave, juicers,
griders, ice makers and food processors. If some circuits are
unaffected, your wall outlets may be wired with aluminum instead of
copper. A few strands of fine copper wire under each outlet screw (and
around the end of the aluminum wire) might fix the outlet problem, if
you have outlet problems. Your Electric Company may be willing to make
some tests at no cost to you.   Neil

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