OCP for shop tools

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jeff43222

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Minneapolis, Minnesota
I had a guy call me today about doing various wiring tasks around his house, and one thing he wants me to do is wire up some receptacles for his table saw and planer. Since I like to follow 110.3(B), I asked to see the instructions that accompanied the tools. The table saw called for not less than #10 wire and protection with a 40A time lag fuse. The planer called for not less than #12 wire and a 20A time lag fuse. Both tools' nameplates listed single phase, 15A, 230V. Both also came with cord-n-plug installed.

My impression is that I must install fuse boxes specifically for this installation and cannot substitute circuit breakers. I don't get a lot of calls for wiring up tools with motors and want to be sure I do this right.
 
Why not give two options to the customer?

1)Simply provide receptacles supplied by standard circuits based on the rating of the factory installed plug.

Tell the customer that this may not provide adequate service (the breakers may trip) and to get the full potential of these machines he will need the time delay fuses.

2)Do it with a fused disconect as per instructions.

I would push the customer toward 2.
 
But you can't wire a receptacle with a 40A fuse and #10 wire. You would have to use #8 for option #2. Correct?

Steve
 
What puzzles me is that the cord-n-plug that is connected to the table saw (5 Hp, single phase) is a 20A, 230V (6-20P in Exhibit 406.3 of the NECH), but the instructions call for no less than #10 wire and a 40A time lag fuse.
How can it be legal for me to install a 20A receptacle for the table saw's plug, but protect it with a 40A time lag fuse? 210.21(B)(1) seems to prohibit it.

The planer has a 15A, 230V plug (6-15P), and its instructions call for a 20A time lag fuse and no less than #12 wire. That one makes sense to me.
 
The situation with woodworking shop tools is something of a mess. Is this the 5HP Delta Unisaw? They used to ship without a cord and plug, and the manual specfied that they be direct-wired. The manual still says that, but now they ship with a cord and a 6-20 plug. If you call Delta Tech Support, they'll tell you the plug is incorrect (it's intended for the 3 HP model), and they'll tell you a 30A breaker as an alternative to the time-delay 40A fuse is OK with them.

Similarly, it seems alot of information the tech writers put in tools manuals, especially some of the imports, is equally confusing and pulled out of the air.

Applying '430 on home shop tools has some issues. One of the biggest is that, if you take 430.108 and 430.109 together, the plug has to be HP rated for the tool's motor. But I've never seen a 3 HP tool with a 3 HP-rated plug, let alone a 5 HP tool.

For the case of a manufacturer-installed cord and plug on an NRTL-listed tool, I'd just call it an "appliance" and 430-109(F) doesn't apply, and wire up a branch circuit with a receptacle and OCP to match the plug. For a 5 HP tool, I'd be inclined to hard-wire and follow Article 430. If the customer wants it plug-connected, see if you can get guidance from the manufacturer Tech Support that makes sense; either in writing or at least record the phone call. ;)
 
Yes -- it was a Delta 5 HP Unisaw. I'm pretty sure the customer wants it cord-n-pluggable, as he is setting up his table saw and planer in his small basement, and he pointed out how movable the tools were. I suspect he's going to want to be moving them around from time to time because he doesn't have the space to have each tool in its own spot and still find them convenient to use.

The 30A breaker in place of the time-delay fuse makes sense to me, considering the information in Table 430.248, as well as the manual's instructions to use #10 wire.

I just put in a call to Delta's technical support and got someone there to give me information that made sense. He said I could protect the circuit with a 30A breaker, and I'd have to swap out the existing 20A plug for a 30A one. He also recommended hard-wiring it, but I'll have to run that idea past the customer to see if he likes it.

Thanks for the useful info! :D
 
steve66 said:
But you can't wire a receptacle with a 40A fuse and #10 wire. You would have to use #8 for option #2. Correct?

Steve
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Correct but that was not what I was trying to suggest.

What I was saying was if it shipped with a 30 amp plug install a 30 amp receptacle with a 30 amp branch circuit.

It would likely work fine for all but the heaviest use, which may never happen.
 
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