240V 30 A Shop wiring

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Old 02-13-11, 02:57 PM
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240V 30 A Shop wiring

I need to run 240v, from the 200 Amp Main circuit breaker panel a distance of 90' to the end of my shop to power a woodworking 3HP machine requiring start-up power of 240 V 23 Amps. What size wire do I need to use???
OR, as an alternative, should I put in a sub-panel 50 Amp box and use a larger wire size to feed that first for 80' and then feed my machine for 25' with a smaller gauge wire from the sub-panel?
If I installed the sub-panel I would also add one other circuit run of 20' for a dust collector that would require a start-up power of 240V 19 Amps.
 
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Old 02-13-11, 03:05 PM
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Is this an attached building to where your main service is? Is the 200 amp already the power in the shop?
 
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Old 02-13-11, 03:13 PM
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240 V 30 A Shop Wiring

This is a new separate 50' X 32' metal building with a dedicated 200 Amp service in one corner. I will be using only one of my machines at a time with the dust collector and the largest load is the 3HP 240v 23 Amp startup table saw. The dust collector and the saw are diagonally across the building from the 200 Amp main Panel, So i am considering installing a sub-panel to feed them across the shop.
 
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Old 02-13-11, 03:37 PM
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There's no need for a subpanel for the tools. You can install a disconnect if you wish, but a 50' run is acceptable. Why are you having to run it 90'? Can't you run it overhead? Will the dust collector be triggered by the saw, or will it be independently switched? Having the dust collector on another circuit would be advisable. What is the running amperage of the saw? At face value 10-3 would work just fine on a 30 amp breaker, if the nameplate specifies that. Or 10 THWN in conduit fastened to the rafters.
 
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Old 02-13-11, 03:57 PM
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I agree with chandler. Just run dedicated circuits for each machine. If you want, run a 3/4" emt run and run both circuits in the same pipe.
 
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Old 02-13-11, 06:13 PM
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240V 30 A Shop Wiring

The shortest distance is 90'. Overhead is further as the building has 12' walls and no ceiling, just the roof. I thought maybe one run to a new smaller circuit panel would be cleaner and better than multiple homeruns with 10/3. The voltage drop with 10/3 for 240V saw (23 A start up and 18 A running) looks to be about 1.9% or 4.5V Drop.
If I had both units through one 50 Amp panel box fed with 6/3 wire the drop to the box would be 3V plus the drop from the box to each machine with 10/3 wire would be about 0.5 to 1.0V more. So I guess it is near the same either way.
The dust collector will be triggered separately with a manual remote.
I would like your opinions on which of these would be the best way?
Thanks in advance for hearing me out and the help.
 
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Old 02-14-11, 05:53 AM
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Your plan is a little overkill, but not against any code. The 6-3 will be expensive. You will need to breaker each tool application properly if you plan on dedicating your 10-3 lines. Don't just throw a 30 amp breaker in there and expect it to protect the circuit. You may find the dust collector will work off a 20 amp circuit with 12-2, not sure how yours is wired. Be cautious and don't over protect them.
 
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Old 02-14-11, 10:59 AM
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Smile 240V 30 A Shop Wiring

Thanks Chandler for the advice.
I'll think about it some more before going the separate panel box route.
I understand about not overprotecting.
Cheers to all.
 
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Old 02-14-11, 11:18 AM
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One thing to consider is will you be adding more equipment in that area down the road? If so, I would go with some type of sub panel in that area. If not 60 amps maybe 100 amps.
Good luck!
Jim
 
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Old 02-14-11, 12:26 PM
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For a shop, I would almost certainly install EMT conduit and metal boxes. Romex cables are far too easy to accidentally pinch, cut, pierce when you're swinging boards around and hanging fixtures on the walls and so forth. I would do a home run of 3/4" pipe from the panel to all the locations you intend to install fixed machines.
 
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