garage addition

richard35 · 01-21-2008, 01:11 PM

Ok this might get a bit long but I need a lot of help. Im converting an attached 2 car garage to a bedroom, bathroom, and small office. I want to replace my existing main with 200 amp service and then add a sub-panel for the garage. What size sub? wire? do I need? Main panel to garage where sub panel is going to be is about 100 feet, but can be run through attic. I will need plenty of power for the bathroom, 2 computers in the office, etc.
Thanks for any help.

220/221 · 01-21-2008, 01:18 PM

I would run a 6-3 with ground on a 60 amp breaker.

You can run a 8-3 with ground on a 40 if you have no AC, heater, water heater load etc.

richard35 · 01-21-2008, 02:00 PM

How do you attach pics so I can send some pics of what I currently have.

richard35 · 01-21-2008, 02:21 PM

OK, here is what I currently have. As you can see the lower box is in the off position. I have no idea why it is even there. There are 2 fuses in that box that are 30 amps each, that makes it a 60 amp panel right? Also I cant read the fuses on the top box so have no idea what size it is, but it does seem to be the one powering the house.
http://pic60.picturetrail.com/VOL170.../299826822.jpg
http://pic60.picturetrail.com/VOL170.../299826805.jpg
http://pic60.picturetrail.com/VOL170.../299826789.jpg

220/221 · 01-21-2008, 03:55 PM

Quote:

As you can see the lower box is in the off position. I have no idea why it is even there.

Follow the cable leading out of it. This was added on illegally as they likely double tapped the lugs at the meter for a...dryer,AC,oven?...something.

Quote:

There are 2 fuses in that box that are 30 amps each, that makes it a 60 amp panel right?

Uhhhh....no. The size of the service is based on the size of the wires. Eyeballing it I'd say beyween 60 an 100 amps. Take a look for the wire size stamped into the insulation. VERY hard to find/read on old wire.

Quote:

Also I cant read the fuses on the top box so have no idea what size it is, but it does seem to be the one powering the house.

Pull the fuse block out and look. It still won't tell you anything. There could be most any size fuess in there.

richard35 · 01-21-2008, 04:27 PM

Ok, lets see if I have all this right then. I install new 200 amp service, use a 60 amp breaker to lead to the addittion. Now I need a sub-panel there to connect to and thus split up the power. Now with the 140 Amps I have left how do I send that to the other indoor panel that supplies the main house? Doesnt the line going to that indoor box need to be just one line right? Thus I would need a 140 amp breaker? Kinda lost I think.

handyman78 · 01-21-2008, 06:56 PM

Is this main located outside? Can you snap a picture of your indoor service panel?

From the look of it for the service you want you will be replacing everything in the pictures. Depending how far your indoor service panel is from the meter, you may need a main cutoff breaker near the meter.

Generally speaking, in common residential service panels, you would have a 200a main breaker, and 30 or 40 breakers within the same box. Coming off a couple high amp breakers in that service panel you would feed the subpanel. All the other breakers in the main box would feed the rest of the house circuits.

Your main breaker would be the master cutoff for any electric circuit after the meter. It is more of a doubling up of protection, not dividing what is left. This I think is where the confusion lies.

220/221 · 01-21-2008, 07:04 PM

1. Install 200 amp service with 2 ground rods, water and gas bond. (I use #4 bare copper on everything to keep it simple)

2. Install 60 amp breaker and 6-3 w ground to garage panel.

3. Install ??? breaker for existing panel. The breaker size is determined by the wire size. X size wire can handle Y amount of current flowing thru it.

Your existing panel is fed with a 3 wire cable and the neutral=ground. Your local inspector might let this pass, he might not. You may have to upgrade the feed to a 3 wire w/ground cable.

richard35 · 01-21-2008, 07:12 PM

Yes i intend to replace all those outside boxes as well as the inside service panel. The inside panel is on the inside directly opposite the existing outside box. My "confusion" is since i have the outside main and inside service panel how do I get the power from the outside to inside? Does the 200 amp main allow me to go directly from it to the inside panel?

220/221 · 01-21-2008, 07:18 PM

There are many ways to set the service up.

How much load is on the interior panel? etc etc.

Call someone

richard35 · 01-21-2008, 07:41 PM

Here is a pic of the inside panel.
http://pic60.picturetrail.com/VOL170.../299874009.jpg

It is completely full so I would want to put in a box a little bigger for future add-ons.

LawnGuyLandSparky · 01-21-2008, 10:28 PM

You have a 100a service. The added disconnect is probably for some specific, added 220v load after the premisis was built. (pool, central a/c, electric range or clothes dryer.) An added bathroom, bedroom and "office" with 2 computers probably doesn't warrant increasing your service size, but your interior panel could use replacing with a 100amp, 30 space panel to accomodate the additional circuits.

220/221 · 01-22-2008, 01:51 AM

Quote:

The inside panel is on the inside directly opposite the existing outside box.

In AZ we put out all in one service/panels outside. If you wanted to do this you could probably get all of your circuits directly into a panel outside.

If not, just use some of the same 6-3 wg on a 60 amp breaker to refeed a new interior panel. It will be easy since it is right there on the same wall. Outside you would have a 200 amp main, two 60's, a 30 to refeed the mystry circuit is necessary and room for future circuits everywhere.

richard35 · 01-22-2008, 05:33 AM

220/221

That all sounds good, thanks for the advice. Ny only concern is if the 60 AMP to feed the new inside panel for the main part of the house is enough.