Two-Speed Motor Disconnects

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whiggins

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I have an installation with a two-speed 20HP motor. The starters are located in a remote MCC. Disconnects are required at the motor location. Can two disconnects be used adjacent to each other for the high and low speeds or does one six pole disconnect have to be used?

The job requires stainless steel disconnects and the 6-pole variety are extremely expensive!

Thanks for your help.

Regards:
whiggins
 
dcspector said:
What about 430.102(B) exception?
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What about it?

Which condition of the exception would you see applying (a) or (b)? :-?

Can two disconnects be used adjacent to each other for the high and low speeds or does one six pole disconnect have to be used?
Click to expand...

Get ready to order the six pole switches, check out 430.103.
 
dcspector said:
"What about it" that was nice.
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:-?

It was a question, you said 'what about a code section' and I am asking what about it?

There really are very few reasons the NEC allows the use of the exception, the cost of the disconnect is not one of the reasons.
 
Also consider NFPA 70E 120.2(A)

Also consider NFPA 70E 120.2(A)

Have you considered locating the disconnecting means directly after the short circuit protection (Feeder CB) where there should be only 3 phase conections, even for a multispeed motor. This is great for a new install, yes it requires you to upsize the wire most likely and depending on your spec possiably even run a second conduit and maybe a third conduit. I might use this a pitch to justify the cost of a six pole disconnect.
 
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