meirman wrote:

In alt.home.repair on Fri, 29 Jul 2005 21:21:49 -0700 Eric
posted:

Jim Beaver wrote:

I've got a newly-built house (well, actually, it's 2/3 new, 1/3
existing)
with new wiring from the panel in. It's got a 200 amp rating at the
panel. But whenever the air conditioning comes on, the lights dim and
power dips much more than I've ever seen in another house, even ones
with lower amps
and older wiring. Sometimes it's enough to shut down my computer or TV.

The wire coming in from the pole is what was here when only the existing
house was here. How likely is it that a problem like this is on the
city's side of the breaker panel?

Jim Beaver
You might want to verify the various wire connections in the panel are
tight and well connected (but only if you are comfortable with things
electrical) A bad connection will cause a voltage drop under load.

This sounds right to me. If the AC and the lights are on different
circuits, and they almost certainly are, that would mean the bad
connection is at the junction or closer to the street than the
junction of them. That is, where the main enters and connects to the
fusebox.

I've done this with my car battery with my bare hand, but I think
doing it with a bare hand in a fuse box would kill me, literally (and
literally doesn't mean figuratively, like people seem to use it.)

But... Is there any sort of rubber glove that the OP could wear that
would insulate from the electricity, but allow him to feel if the
connection is hot, physcially. That's how I could tell where the bad
connection was on the car battery. The good one was cold, the bad one
was almost too hot to touch. Of course that was a really bad
connection, so bad the car stalled and wouldn't crank fast enough to
restart. The op's connection is still working, but I think it would
be warm all the time, and a bit hotter right after the AC starts up.

Or is it too dangerous and he should just tighten that connection with
a well insulated screw driver and gloves?



begin sidebar
By any chance... are you using Aluminum wire? If so, i highly recommend
you rip it all out and get what you can for scrap price out of it. AL is
ok in very large sizes (as long as its correctly installed with proper
torque and an anti-oxidant on good clean connections), oh say above 00 but
even still, I'd go all copper if i possibly could.
end sidebar
I really doubt its a utility transformer problem, but I'll bet dimes to
donuts its either a bad main breaker or a bad connection in your panel,
either at the mains, the meter or one of the bus bars in the panel.
Eric


Meirman
--
If emailing, please let me know whether
or not you are posting the same letter.
Change domain to erols.com, if necessary.

FIRST: dont be doing that kind of crap on electrical equipment.
Use the proper tools. Do it right and get good results with no
damage to the equipment or injuries to yourself or others.

OK:
Its easier and much safer to just measure the voltage drop across the
connection with a voltmeter, here's a sample of measuring the drop across
the L2 connection.
--------@------- L1
-----------@---- N
-------@-------- L2
^ ^
| voltmeter|

notice I'm measuring NOT line to line or line to neutral? I'm measuring
across the connection on a single line. The idea is to see how much voltage
is dropped across the connection and thus to gain an idea of how good the
connection is. Ideally you would read Zero volts if the connection were
perfect. Of course this all has to be measured with a fair amount of
current flowing through the connection - I'd recommend at least 25% of its
rated load if its possible and 100% of its "normal" (not rated, but normal
- what it usually runs at) load is great. If you know the exact amps then
measuring the drop will allow you to calculate the actual connection
resistance. But barring that, if you put a decent load on it and measure
anything more than a few volts its a problem. Also, just cuz your measuring
on a single line dont forget it can kill you in a heartbeat. Be Carefull!
Think about keeping yourself out of contact with the line wires and bus
bars etc, put on shoes with rubber soles, dont do it in your garage in bare
feet.
Eric