Sounds like a loose connection - but where? The first place I would
check is the circuit breaker. Aluminum wiring is well-known as a fire
hazard because it's such a good conductor of heat and it expands and
contracts so much (compared to copper) that terminations eventually
loosen over time and get warm as they do (because of resistance) and as
they warm, they expand and then contract when the switch is turned off.
Every time the switch cycles (gets turned on and off) the wire warms
and cools further loosening the connection until you start having the
"brown out" condition you describe. Sometimes there will be an arc in
the loose joint and the condition will disappear for a while (the wire
actually welds itself) until the heat/cooling cycle builds up enough to
break the little weld and you're back to the brown out condition.

Somewhere between the circuit breaker box and your fixture there is a
loose connection and I would consider it VERY unsafe and a potential
fire hazard. Find a different electrician. No self-respecting
electrician would EVER leave a homeowner with the described condition,
furthermore if that electrician wants to keep working and avoid having
the liability of a fire (and all the consequences that can accompiany
that) on his record.

Jeff



bardsapprentice wrote:
We've lived in a home for 20 years that was built in 1970. It has
aluminum wiring. Over the years we have a consistent problem with a
kitchen light in the middle of the ceiling browning out after we turn
it on. It turns on just fine and a few seconds later it dims and then
goes back to full light. It might never do it again or it might repeat
this. We've been unable to establish a pattern.

We've been all over the house and exterior trying to tie that
particular behavior with appliances turning on or off, the washer
changing cycles or something and can't. We've had three separate
electricians try to diagnose and fix the problem but they keep trying
to say that it's a general brownout of the neighborhood when it clearly
is not.

We've changed the switches in the kitchen and elsewhere and "pigtailed"
the switches. I'm imagining that if there were a danger of fire we
would have had one by now so I'm assuming this is not a clearly unsafe
condition. One neighbor suggested that if there one non-aluminum line
on a circuit that this might be the source. Someone had added some
wiring before we bought the house. Does this make any sense or can you
suggest another direction to look?