PDA

View Full Version : Check of shop wiring, please



baz67
03-05-2006, 05:10 PM
I have done plenty of wiring, but I have never had to calculate anything. My concern is that I have the have enough capacity in my figures. I have 150A service to the house. I calculated the house needs 75A of that. The house is 1800 sqft with a gas dryer and stove. The basement is 900 sqft and the garage is 400 sqft. 400 sqft of the basement is shop and storage. I want to put a 40A subpanel for the basement and garage. I plan on running a 8ga feed line from the main to the subpanel. I plan on having seven circuits on the subpanel. They are as follows:

Air compressor 20A/12ga switched
Welder 20A/12ga
Drill press/saw 20A/12ga
Shop outlets 20A/12ga
Shop lights 15A/14ga
Garage 15A/14ga
Spare room 15A/14ga

Does that seem alright?

vintageracer
03-06-2006, 09:26 AM
Depending upon your welder and air compressor sizes/capacities, you will probably need at least 30AMP circuits for those pieces of equipment. Again, this depends on the size/output of the units.

Look at the motor specification label on the compressor and the spec sheet for your welder. The electrical requirements will be listed on those labels/operating manuals.

chet
03-06-2006, 09:42 AM
I have 160 amps coming into my house. 1300 sq. ft. with electric drier and heat(electric boiler) I have a 60 amp circuit to the shop and have a big compressor running off a 40 amp breaker. Apparently our barn lights also run from the shop somewhere (I can't find it, but when I throw the shop breaker the barn lights go off!) I have NEVER had a breaker pop. I make sure the compressor is unplugged before I plug the welder in.

parsonsj
03-06-2006, 10:07 AM
Yes, the welder number is suspect. My TIG uses a 50A breaker at 220V. Make sure you can handle both the welder and compressor simultaneously ... it would be very annoying for the compressor to kick in and kill the welder mid-bead.

What kind of lights are you planning? Florescent will be fine at 15A; halogen won't.

jp

baz67
03-06-2006, 11:50 AM
Thanks guys. The welder and the compressor will have decicated circuits each. The compressor uses a 15A@120V motor. The welder is a Miller 135. I do plan on upgrading to a 175 in sooner or later. So then would 30A/12ga be alright for the welder. JP, only your are crazy enough to use those nice and cool halogens in your shop. I plan on using florescent in both the shop and garage.

toxicz28
03-06-2006, 03:23 PM
So then would 30A/12ga be alright for the welder.
I would go 30A/ 10ga for the welder up to 50' of cable. Anything more, I would use 8ga wire.