Garage Electrical

[william.m.hamilton2]

Okay-
We are finally upfgrading the garage power, I am having it contracted, the house was brought up from 80 to 200 amp. Now I need to decide what to do with garage. originally I was quoted for two circuits only. Put the cabosh on that, we are going with a sub-panel. Now I am getting quoted a 240 volt 30 amp. That doesn't quite seem enough amperage to ever step up to anything with a large draw, for example, a welder, big 240 compressor, etc.

I am a mechanic by trade, and would like to have this as my retirement shop (ya know, in 90 years). I am thinking of taking some welding classes in the future.

I am mainly interested in taking up body work with welding. Nothing massive.

I currently have a smallish upright 120 compressor, but it is a newer I/R unit and I am sure its life span is shorter than I would like.

I am open to suggestions. I also want to have two outlets on each side wall, and three on the back wall (longer wall).

I am also intending to run a fixed piping sytem for my L/P air on the drywall when I complete the garage.

Any pointers on the appropriate amperage for all this? I know bigger is better, and I would love to have a second independant feed, just for the garage, but money isn't there for that.

-Will

 

[Stuart in MN]

A 100 amp panel would be nice, but chances are a 60 amp panel will be more than enough.

 

[sberry]

30A is not enough, the panel you would use would be 100A and there is no reason not to wire up to that, makes a great source to weld from as well as helps motor starts and saves secondary wiring.

 

[william.m.hamilton2]

I am sure we have plenty of power. The 30 amp is just what the electrician quoted us for and it seems low to me. L/P as in Low pressure air.

Assuming there is sufficient power, is upgrading to 60 or 100 amp a huge price differential?

 

[C96]

I would do no less than 100 amp

 

[pattenp]

I agree with the 100A sub feed. I think you'll find it's not a huge price jump if you're talking about a sub-panel fed with 30A vs 100A. Depending on the sub panel used you may be looking at $50 to maybe $100 more in materials for the 100A. This is just a wild guess because it really depends on what materials are used in one scenario vs. another.

 

[william.m.hamilton2]

What about the wires feed in the sub panel? Is there going to be a big jump there? Looking at a run of 50' with the wires burried from house to garage. Two foot depth of trench (I dig that so we aren't paying electricians to dig holes). Two ground rods for garage already in quote. So basically I would be looking at another $50 or so for larger sub panel. I assume the wire from panel to panel and the main breaker will be another $200. Does that seem right?

Thanks!

 

[Mustang51js]

Call your electrical supply house and ask them how much a foot for number 1 aluminum and multiply that by 220 feet. Main breaker sub panel is around $60 and another $100 in pvc pipe and breaker for main panel.

 

[pattenp]

10-3 Cu UF is about $1 a foot. #1 Al XHHW is about ($.50 X 3) a foot and #4 or #6 Al XHHW for the ground is around $.25 a foot. So you are looking at $1.00 a foot for a 30A feed vs. $1.75 a foot for a 100A feed. This is just a rough estimate for the wire only.

 

[sberry]

At first it was assumed this was an attached garage,,, this is a separate building?

 

[volleyball]

For 30a, I would not bother. 60A minimum and 100a all the better. Do you really want to do this twice?
Run a second conduit with some coax and a couple cat cables in it closer to the surface while you are at it.

 

[pattenp]

I thought that too when william.m.hamilton2 said he was quoted for 2 circuits but opted for the sub-panel. If it was an electrician that quoted 2 circuits to the garage then he better get a different electrician since 2 circuits feeding to a detached garage is against NEC. May be he meant just 2 circuits in the garage.... who knows.

At first it was assumed this was an attached garage,,, this is a separate building?

 

[william.m.hamilton2]

It is detached, and yes I meant two circuits in the garage. One for opener and one for general use and lighting.