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210.63 Equipment Requiring Servicing.



A 125-volt, single-phase, 15- or 20-ampere-rated receptacle outlet shall be instal⁠led at an accessible location within 7.5 m (25 ft) of the equipment as specified in 210.63(A) and (B).
(A) Heating, Air-Conditioning, and Refrigeration Equipment.



The required receptacle outlet shall be located on the same level as the heating, air-conditioning, and refrigeration equipment. The receptacle outlet shall not be connected to the load side of the equipment’s branch-circuit disconnecting means.

 

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I have seen those combo disconnects before but when I looked I was not satisfied with the internals, some I have seen do not have breakers dropping down the current for the outlet.
Every time I have used the tap rules I get in trouble so I avoid them and use a plane old disconnect and and a GFCI in another WP box.

I feed the receptacle with its own 20 amp circuit.

 

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?

All grounds get tied together.