In article .com, "brianlanning" wrote:
A few years ago, I put a subpanel in my garage/shop. I had a black and
decker book with detailed photos. I'm certain I followed code, and
everything worked perfectly. I had a 220v breaker in the house panel,
and a 60amp subpanel in the garage with i think 6 breaker positions. I
feel very confident that I could do this again safely.

Good so far... always glad to see someone who took the time to learn how to do
it right.

I recently moved. And I'm getting ready to do the same thing again for
the new house. The only thing I want to do differently is to have more
circuits. I want three 220v breakers for the dc, compressor, and
whatever tool is running. I also want at least two 110v lines, but
more like three or four: 1 for tools, and 1 for lights, also future
expansion just in case. In addition, I can't rule out the possability
of adding a huge tool. I can see getting a killer deal on a 3-phase
machine and putting in a rotary convertor for example. Or maybe
something with a 7.5hp or 10hp motor. So I want to be able to handle
higher currents just in case.

Yep. Good thinking.

I just so happen to have a 100 amp panel. It looks a little different
from the other subpanel I had though. It looks like it's meant to be
the only panel in the house. My old one didn't have a 60amp breaker in
it. It relied on the breaker in the main panel, with the feed wires
going into screw terminals on the bus bar. This one has a 100 amp
breaker in it. It looks like I can't remove it. Am I missing
something?

What you're missing is the notion that this is *exactly* the kind of panel you
want for a subpanel in your shop - in an emergency, if you want to kill all
the power in the shop RIGHT NOW, you have the disconnect right there at the
subpanel. You don't have to go back to the main.

How should I handle this? Ignore it and put, for example, a 60amp
breaker in the main panel and the right gauge wire for 60 amps? Or go
with a 100 amp breaker so that it matches the one in the subpanel
(assuming fat wire for 100 amps)? Or a different subpanel that has no
breaker?

Option 2 - go with a 100amp breaker in the main panel, and 100A-rated
conductors to feed the subpanel. You need *four* conductors: two hot, one
neutral, and one ground. In the subpanel, you must have separate neutral and
ground bus bars, and they must *not* be connected together. Note that
"connected together" also includes "connected to, and not insulated from, the
case of the panel" even if there is not wire connecting them directly.

(If the panel you have now does not have separate bars for neutral and
ground, don't worry - you can buy grounding bar kits at any home center or
major hardware store.)

Option 1 is ok, too, but you may find later that you want the extra power.
It doesn't take any more time to run wires for 100A than for 60, and doesn't
cost too much more, either. Likewise, the price difference between 60A and
100A breakers is not great.

Option 3 is IMO a non-starter: it's a needless expenditure to purchase
equipment that is *less* suited to the task than what you already have.

I don't really need 100 amps.

Not yet, anyway, not until you get that rotary phase converter. Then you
might, depending on how much else you have. :-)

It also has a lot more positions than I
need (like double!).

Extra capacity is a good thing.

But at the borg, they have the little rinky dink
subpanel I have in the old house. Then the next size up is this 100
amp monster.

See above. :-)

Should I put in two of the smaller panels, sort of
daisy-chaining them? or run both subpanels back to the main? seems
silly.

It *is* silly. :-) Go with the 100A panel you have.

--
Regards,
Doug Miller (alphageek at milmac dot com)

Nobody ever left footprints in the sands of time by sitting on his butt.
And who wants to leave buttprints in the sands of time?