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#169533 - 10/07/07 03:46 PM Cord and Plug as disconnect
nrp3 Offline
Member

Registered: 10/06/07
Posts: 27
Loc: New England
I am wiring a wood shop and have to hook up a drum sander. This is 230v 1 phase. We are going to install floor boxes for the machines in the center of the work area to avoid cord drops being in the way. This particular machine doesn't come with a cord, though the manual implies that you can wire it with a cord and plug or hardwire it. The owner wants it cord and plugged. It has a 5hp and a 1/4hp motor. All it mentions is to use a UL/CSA listed cord and plug. 430 mentions that to use a cord and plug as a disconnect for motors, it must be hp rated. I can't for the life of me find a 5hp or better rated single phase cord. The owner found another machine (different brand) that is 5hp with a permanently attached dryer cord on it and wonders why that one has it. This isn't an appliance and it falls under 670 which doesn't help either. What am I missing here?

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#169534 - 10/07/07 04:56 PM Re: Cord and Plug as disconnect [Re: nrp3]
gfretwell Offline

Member

Registered: 07/20/04
Posts: 9012
Loc: Estero,Fl,usa
I see your problem
When I look at a 6-50 they just list that at 3HP. The same site has a 6-30 that says 2HP
http://www.stayonline.com/detail.aspx?ID=4740
They must want the plug to be rated for LRA or something.

All that said I have a 5HP pressure washer that came with a factory installed 6-30. It is a GFCI plug that is "new standard" so it has to be reset after the power is applied so the plug should never be able to be inserted against LRA.
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#169538 - 10/07/07 06:42 PM Re: Cord and Plug as disconnect [Re: gfretwell]
nrp3 Offline
Member

Registered: 10/06/07
Posts: 27
Loc: New England
My gut tells me it will work fine. It seems to be part of other pieces of listed equipment. I'd just like to know how to justify it.

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#169544 - 10/07/07 08:19 PM Re: Cord and Plug as disconnect [Re: nrp3]
gfretwell Offline

Member

Registered: 07/20/04
Posts: 9012
Loc: Estero,Fl,usa
I doubt you would have a problem if you also had a disconnect other than the plug. If the plug is your disconnect it needs to have a 5.35 HP rating and from what I am seeing that is probably close to a nominal 100a plug (6-50 is 3HP).
My pressure cleaner has a 2 pole switch with an "off" position marked.
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#169547 - 10/07/07 08:58 PM Re: Cord and Plug as disconnect [Re: gfretwell]
nrp3 Offline
Member

Registered: 10/06/07
Posts: 27
Loc: New England
Looking at some of those pin and sleeve plugs, they don't have horsepower ratings. The only ones that do are the ones that have a disconnect switch included. They are incredibly expensive. Anyone else?

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#169549 - 10/07/07 10:31 PM Re: Cord and Plug as disconnect [Re: nrp3]
gfretwell Offline

Member

Registered: 07/20/04
Posts: 9012
Loc: Estero,Fl,usa
I am open to another opinion but I would probably be OK with you putting a HP rated disconnect switching device on the machine and using a 6-30 plug.
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#169554 - 10/08/07 04:11 AM Re: Cord and Plug as disconnect [Re: gfretwell]
electure Offline

Member

Registered: 12/24/00
Posts: 4225
Loc: Fullerton, CA USA
Will the circuit breaker in the panel qualify as the disconnect? (within sight and <50 ft). Or, can a disconnect be mounted before the conduit goes underslab?

Another issue I see is that you're going to have a heck of a time finding a suitable cover listed for the purpose for your floor box. Also, a receptacle facing up in the floor of a wood shop can't be too good a thing. A drum sander makes some pretty fine dust. Is this location subject to Article 502?

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#169559 - 10/08/07 05:20 AM Re: Cord and Plug as disconnect [Re: electure]
nrp3 Offline
Member

Registered: 10/06/07
Posts: 27
Loc: New England
The panel is in the other room, so that won't work unfortunately. Thomas and Betts sells a tombstone that attaches to a floor box cover plate with a 1 inch threaded nipple. They sell a cover plate for that which will accept the large dryer/range size receptacle. Solves that problem or use the plates with the large threaded plug for a twistlock. In the end I will probably just do it, though with a cord end from Hubbell, not a store bought dryer cord.

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#169560 - 10/08/07 05:40 AM Re: Cord and Plug as disconnect [Re: nrp3]
nrp3 Offline
Member

Registered: 10/06/07
Posts: 27
Loc: New England
As for the hazardous location. I think it might be a stretch, but it might fall under class 2 div 2 G. This isn't a shop that would be producing daily, if it was, not much volume. There will be a dust collection system as well. Its more of a hobby thing at the moment, though it still needs to be done correctly.

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#169567 - 10/08/07 09:21 AM Re: Cord and Plug as disconnect [Re: nrp3]
gfretwell Offline

Member

Registered: 07/20/04
Posts: 9012
Loc: Estero,Fl,usa
I don't see any reason why the disconnect can't be on the machine end of the line cord, attached to or incorporated into the machine.
... but I have been wrong before.
IMHO if you don't need to pull the plug under load (disconnect function) it only needs to be rated for the BC OCD.
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Greg Fretwell

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