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tactical
Feb 27, 2013, 07:47 PM
I have a house on my farm, 330 feet away is my new woodworking shop. I can power the shop in 2 ways and would like to know which one is the best. With option A, I can have a single meter dual 200 amp service panel base. One line to the house and the other would be to the shop via 4/0 Qualplex service underground. The shop would have a 200 amp service panel in it. With option B, I would have a single 200 amp service panel in the house and run a line to a 100 amp sub panel in the shop via 2/0 Quadplex. Power from an overhead line is too expensive and the 200 amp shop panel and wiring cost twice what the 100 amp sub panel would cost. According to the amp draws from the motor tags, the 100 amp panel is sufficient (including the 80% amp drop due to the line length). I have a single phase air compressor that draws 29.7 amps, the other machinery is 3 phase machines running from a 10 hp Rotary Phase Converter that pulls 26.8 amps on start-up and 13.4 amps at idle. My 5 hp dust collector and table saw draw 13 amps at start-up and 6.5 amps running. I'm a 1 man shop so I would mostly have only 2 machines running at the same time. Which set-up do you guys recommend?

donf
Feb 28, 2013, 08:51 AM
You really need a licensed electrician do a load calculation for you and plan the shop for you.

First, you cannot have a 80% VD. From the beginning to the you are limited to no more than 5%. Using a VD calculator the cable size was 250 kCMIL.

Next, since this is a wood shop, it needs to be treated as a Class 2 explosion site because of the dust. That means dust proof covers for receptacles.

Also, how are you planning on handle the ventilation and dust capture.

I didn't see any planning for lighting?

tactical
Feb 28, 2013, 10:18 AM
Thanks for your response.

Concerning the voltage drop, I mistakenly said a 80% drop when I meant to say that I realized that I would only be getting 80% of the amps at the shop and not the 100 amps.

The dust collector is in a separate building.

Most machines are hard wired but what few plug-ins I have will be the covered type.

As far as lighting, I will have 5 rows of 12' of flourscent lights made up of an 8' and a 4' in each row (2 bulbs per fixture).

Yes, I will get an electrician to review what I have and have him do the load calculation and make the final plan.

Thanks again.

hkstroud
Feb 28, 2013, 03:34 PM
The drop is in voltage not amperage.

You should first calculate what the maximum demand is (amperage and at what voltage),

The factors that determine voltage drop is cable size, distance and amperage draw.

4/0 Aluminum cable at 300'

80 amp 4.1 volts
60 amp 3.1 volts
30 amp 1.5 volts

2/0 Aluminum cable
80 amp 6.5 volts
60 amp 4.9 volts
30 amp 2.4 volts

First calculate you demand load and then chose the cable size.
You stated the amperage of your machinery but not the voltage.
I would use the running amperage. Your minimum amperage draw would be you lighting, possible air filtration system and shop vacuum plus largest piece of equipment. I would also add the amperage of the next largest piece of machinery, you might have a friend come over and help you on occasion.

I would also add a fudge factor, you don't want to save a dollar now that will cost you ten later on.

I see no advantage of having
single meter dual 200 amp service panel base over a breaker in you house panel unless you existing panel is too small or over filled. Size of cable would not change depending on which way you set up at the house. Size of panel in shop would not need to be larger than 100 amps.

From you vague description I would guess you minimum demand would be around 40 amps. A 60 amp service would be adequate. I would probably go for 80 amps.

In my shop I have a 12" table saw, band saw, drill press, router table, radial arm saw, large industrial wood shaper, lathe, air compressor, dust collector, thickness planer, planned/jointer, belt sander, various chop saws and a couple grinders.
I have 55 amps running to the shop, never had a problem.

What about heating and cooling? I strongly recommend an air filtration system. I don't have one and everything is cover with a film of dust. Not good for the breathing. I keep saying I going to put one in. When I occasionally decide to clean it is a real chore.

You should really consult the power company about a new service to the shop, 300' of 4/0 cable and installation will expensive.