wrote:
Thanks everyone for the insights. I hadn't thought about the
increased load on startup and how that could be enough of a pull to
affect other circuits in the panel. I'll put my kill-a-watt on the A/
C and see if I can see what it draws during the startup (it might not
be fast enough to see, though).

To answer some questions:

If the lights are flickering, you have a loose connection. If the lights are
dimming when a motor starts, it's normal

I suppose technically it's a dim. I just wanted to distinguish it as
a very quick dimming (quick in that it dims down and then back up very
quickly) from what I used to have when the floor was all one 15A
circuit---back then the A/C would come on and everything would dim and
stay dimmed until the compressor shut off.

The compressor may be pulling as much as 40 or 50 amps upon startup which
would cause your other circuits to be affected.

Ok, so since this is a 120V A/C, I suppose I should only be seeing a
dim on other circuits that share that same side of the panel (e.g. the
same single hot wire from the main)? I'll have to take a look and see
if that's indeed the case. Or is the 40-50A 120V pull on one leg
enough to affect the other side of the panel?

#4 wire was better choice. Doing all this work, did you you take
out a permit? Just wondering. Where I live we need a DIY permit from
city and two inspections, during, after the work is done.

I did take out a permit. The inspector was great. We went over my
plans before I started, he came out early on before I'd finished rough-
in to make sure I was doing things correctly, then he checked the full
rough-in, then a final. He approved the #6 for 60A. As I recall it
rates for around 55A technically but the NEC allows you to round that
up. I also had a long thread on this group discussing the feeder wire
back then:
http://groups.google.com/group/alt.h...af96b1ca6205f6

The run is about 35' from the main. Part of the reason I wanted to go
with #6 was flexibility in getting from the basement to the attic.

Looking back at my old thread, it makes me realize I should probably
check and make sure I balanced the loads well on the two sides of the
panel. I meant to, but I'll double check.

Do this on both sides of the
240 circuit. If the drop is much more than calculated above then
something
is amiss.

Thanks for this. I'll try this out and see what I find. I'll also
look up Ohm's law...

You might consider installing a "Kickstart"
hard start assist on your AC unit. It could
eliminate the light dimming.

http://www.kickstartoem.com/faqs/homeowner.html

[8~{} Uncle Monster