The wire from the main panel to teh garage is less than 100' ,
approx.75'. The wire from the main panel goes only to the garage
nothing else. With this length the voltage drop is is about 5 volts.
The electrician that put the 20amp circuit in the garage panel did not
know that the breaker in the house coming to the garage was only 15amps
I guess he just assumed that it would have been higher.

Thanks Again for your help
Stuart
Scott Townsend wrote:
A #10 wire is good for 30 Amps, though you would need #10/3 to get your 220v
for the heater. The breaker would be a 2 Pole Breaker (either a Double, or a
Quad with the inner/outer connected.

Like Toller mentioned. Make sure that the #10 from Breaker to Panel is the
only thing that connects the two panels together. Does the Garage have a
Main or is it wired into lugs at the top of the panel? Should be wired into
Lugs and the panel should be rated for the 30amps or better.

Scott-
wrote in message
ups.com...

Toller wrote:
wrote in message
ups.com...
I have a 15amp circuit breaker from my main panel going to my garage
panel. The wire going to the panel to the garage is 10awg. I was
wondering if i could change that circuit breaker to a higher one. I
have a 220V heater that is 20 amps that keeps tripping the 15 amp
breaker on the main panel. Could I go to a 30amp breaker on the main
panel to the garage? On the garage panel there is 2 15amp circuits and
the 2pole 20amp circuit for the heater.

Probably. Naturally you will want to be certain there is nothing on the
circuit that can't handle 30a; though I can't think of what there could
be...
You also have to figure out how long the cable is, what the load is, and
the
voltage drop. Do a search on VD calculators.
If the only load on it is the heater and some lights, VD isn't all that
important. If you have motors or electronics, much more so.
In short, there could have been a good reason for the 15a breaker; make
darn
sure there wasn't before changing it.

The reason of the 15 amp breaker on the main panel was that when they
put in the garage panel it only had the 2 15amp circuits (one for the
lights and one for the outlets). I got the electrican to put in the
240V 20amp circuit a few years later for the heater. So would i need a
30amp circuit breaker going to the garage or could i go with a 20amp
breaker