Convert 220 circuit to 110 circuit to be run to new subpanel

Discussion in 'Electrical Forum discussion & Blog' started by C Willard, Oct 24, 2009.

1. C WillardNew Member

Joined:
Oct 24, 2009
Location:
Texas
I have an existing 220V circuit running to my garage using 10-3 with ground wire. I want to convert this circuit to 110V adding a subpanel to the garage and run to recepticles. There will be a freezer and refrigerator.

Do I use a 30 amp double pole circuit breaker at the main panel and run neutral, red, black and ground to the subpanel?

How many 20 amp circuits can I add to the subpanel. If only one, can I add a 20 and a 15 amp?

I know an alternative is converting to 110 V single pole breaker at the main panel with only 1 110V 20 amp circuit, but is it enough for the freezer, refrigerator and more recepticles.

Last edited: Oct 24, 2009
2. hjModerator & Master PlumberStaff Member

Joined:
Aug 31, 2004
Occupation:
Plumber
Location:
Cave Creek, Arizona
circuit

Your 220/240 v wire is actually TWO 110/120 circuits. Connect it to the new sub panel, and then install your new breakers in such a way as to spread the load between the two feeds.

4. C WillardNew Member

Joined:
Oct 24, 2009
Location:
Texas
What are the maximum number of circuits and amps per circuit that can come off at the subpanel

5. AlectricianDIY Senior Member

Joined:
Jun 15, 2007
#10 wire = 30 amps per "leg"

You can put as many 20 amp circuits as you like on it but if you draw over 30 amps the main breaker will trip.

6. C WillardNew Member

Joined:
Oct 24, 2009
Location:
Texas
What's the maximum breaker I can use at the main panel with the 10-3 wire. Can I go higher than 30 amp at each pole?

7. jadnashuaRetired Defense Industry Engineer xxx

Joined:
Sep 2, 2004
Occupation:
Retired Systems engineer for defense industry.
Location:
New England
Any single cb must be at or below the max on the wire feeding it, so with the incoming wire you have, no individual breaker after it can be greater than 30A. That does not mean that you can't have individual breakers AFTER that feed that exceed the total. IOW, you can have the sum of the breakers in the subpanel exceed 30A as long as the wires used and the breakers selected individually don't exceed 30A. That way, no set of wires capacity would be exceeded, since the branch breaker or the subpanel feed's breaker would trip first.

Joined:
Feb 20, 2008
Location:
USA
What code cycle are you under?
How much will the permit and inspection cost?

9. hjModerator & Master PlumberStaff Member

Joined:
Aug 31, 2004
Occupation:
Plumber
Location:
Cave Creek, Arizona
breaker

You can only use a 30 amp, or smaller, breaker at the main panel to feed the #10 wires. WIth 110/120 at the sub panel, you will probably use 15 and 20 amp breakers. Try to balance the loads on both feed wires to even things out.

Joined:
Jun 15, 2007