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Joined: Feb 2003
Posts: 7
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Hi All,
Sorry to waste nandwidth but I have been unable to find an answer to this. I am hooking up some 230V woodworking machines and have 2 questions:
1) The NEC implies that each motor over 1HP needs its own protected circuit - Is that true for a 'one user shop' i.e. can I have my frequently used 2HP dust collector and my infrequently used 2hp jointer on the same 220v circuit?
2) When wiring the 220v only machines - The machines have 3 conductor plugs - I pulled 10/3 wire - what do I do with the unused conductor - do I just tie it off at the machine, connect it at the box, not connect it ???
TIA
Ray Bahr
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Joined: Jan 2003
Posts: 53
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rayb,
As long as the motors have internal thermal overload protection you may install them on the same circuit (assumes 2 x 2hp = 24amps, which is 80% of 30 amp breaker protecting #10awg conductors) My recommendation would be to install 30amp receptacles, and cord and plug connect the tools.(no one piece of equipment may draw more than 80% of cicuit capacity) The unused conductor should be wirenutted and/or securely taped at both ends.
Len
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Joined: Feb 2003
Posts: 7
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Thanks Len,
So, I will pull a 10/3 circuit for my DC and Jointer with a 30A breaker, and I will wire nut/tie off the unused wire.
Ray Bahr
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Joined: Jan 2003
Posts: 73
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I believe to answer your question properly you have to identify the Hp of each motor and # of phases for each.
You imply one is single phase and the other three phase?
If so you cannot use a 3 pole breaker to protect a 2 pole load (breaker may not see full fault and trip)
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Joined: Feb 2003
Posts: 7
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Sorry for the confusion. Everything is single phase
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Joined: May 2001
Posts: 552
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I pulled 10/3 wire - what do I do with the unused conductor -(first post)
{2nd post}So, I will pull a 10/3 circuit
Donnie
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Joined: Dec 2002
Posts: 59
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The unused conductor needs to be bonded at both ends.
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Joined: Jan 2003
Posts: 4,391
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The unused conductor needs to be bonded at both ends. I have never heard of this can you name the code? Bob
Bob Badger Construction & Maintenance Electrician Massachusetts
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Joined: May 2002
Posts: 382
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Sorry, I may have missed something here but if these are 240V circuits only and not 120/240V ones, why not use 10-2 instead. Casual enquiry shows a cost saving of around 30%. Paint or tape the exposed white wire black (200-7 Exception 1).
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Joined: Feb 2003
Posts: 7
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Actually for 2 reasons:
1) I have the 12-3 wire. 2) If I ever move things around and decide to run 120/240v circuits I will just need to hook up the 'spare' wire.
Ray Bahr
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Posts: 4,116
Joined: October 2000
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