We have a piece of equipment with a 480 VAC 30 A twist-lock Plug and was wondering if it would serve as a valid disconnect means
Depends on what the equipment is. 422.16(A)&(B) allows the use of cords on appliances.
It is a Hoist.
Due to the fact you have not provided a lot of details on the actual "hoist" I would prompt you to view Article 610 and more specifically Part IV in terms of disconnection means. Only you at this point know your installation parameters and the details that may or may not put you within the scope of Article 610. So read the scope of section 610.1 and if determined to be in your scope of work look at sections 610.31 and 610.32 and notice that it will refer you back to section 430.109. Most notably section 430.109, subsection (f) says the following:
(F) Cord-and-Plug-Connected Motors. For a cord-and-plug connected motor, a horsepower-rated attachment plug and receptacle, flanged surface inlet and cord connector, or attachment plug and cord connector having ratings no less than the motor ratings shall be permitted to serve as the disconnecting means. Horsepower-rated attachment plugs, flanged surface inlets, receptacles, or cord connectors shall not be required for cord-and-plug-connected appliances in accordance with 422.33, room air conditioners in accordance with 440.63, or portable motors rated 1∕3 hp or less.
REMINDER.....do not forget to also read section 610.31 and 610.32 in full detail......Why....because while I give you a reference to 430.109(F) for cord and plug connections, it is only to establish this is what you WANT to do but based on the language in section 610.31 and 610.32 and subsequently 610.33 I do not believe it is an option. However, depending on the location of your hoist you may not need an additional disconnection means at all.
Again review those sections and it will be come crystal clear for you.....
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