Air Conditioner service disconnect / fuses

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Old 08-10-15, 09:06 PM
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Air Conditioner service disconnect / fuses

I am installing a Quick Disconnect for a Mini-Split A/C condenser. The condenser (240V) requires a neutral conductor.

My question is do the neutral and ground conductors have to be electrically separate as the do in a sub panel?

Further, does the disconnect have to be fused or is the breaker in the main panel adequate for overcurrent protection?

Thanks,
-dmd-
 
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Old 08-11-15, 07:08 AM
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The ground and neutral must be electrically separate. The neutral should not be disconnected by the pull-out disconnect switch, only the two hot conductors. The disconnect should be fused if the A/C manufacturer specifically requires it. Otherwise it can be an unfused disconnect with a proper breaker size according to the Max OCPD and Min Ckt Ampacity ratings from the A/C manufacturer.
 
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Old 08-11-15, 03:23 PM
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Further, does the disconnect have to be fused or is the breaker in the main panel adequate for overcurrent protection?
What is the MOCP from the data plate? 25 amp 2 pole breakers used to be quite rare and available by special order only, but since A-C units have gotten more efficient, 25 amp breakers are readily available at most supply houses and even at many box stores. If the MOCP is 35 amps, I would feed a 60 amp disconnect with a 40 amp or higher circuit and install 35 amp fuses. Some units will have a maximum fuse size on the data plate. I have seen a few inspectors who interpret that to mean that protection must be provided with fuses.

For the most part I like a 60 amp non-fused disconnect that can be purchased for under $6.
 
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Old 08-11-15, 07:09 PM
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If the nameplate states maximum fuse size, fuses must be used. If it just states maximum overcurrent fuses or breakers can be used.
 
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