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I am trying to determine the standard practice for installing mini-split systems. Does the indoor unit require a separate electrical disconnect within sight of the unit? Assuming the indoor unit derives its power from the outdoor unit, is the disconnect for the outdoor unit sufficient for both?

If you don't see a disconnect, do you call that out as a correction item?

Thank you

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I know that Mitsubishi requires a disconnect for the indoor unit. Not sure about the other manufacturers. Doesn't the NEC require it in Article 430?

I've seen them wired with in-line switches, cord & plug sets, & no disconnects at all. So far, I haven't called the lack of a disconnect at the indoor unit as a problem.

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Thanks

I am researching this to come up with a consistent policy for our jurisdiction. Jim - I've asked this question in quite a few places, and so far you are the only person who seems to have found these on a frequent basis. I have never seen a disconnect for an indoor unit. The thing that California calls a mechanical code requires an electrical disconnect "adjacent to" any appliance regulated by that code and operating at more than 50 volts, yet it doesn't take much imagination to think of a few instances where that is never enforced (range hoods for one). The electrical code gives a pass to appliances that don't take more than 300 watts, which would include these indoor units. In the NEC, the branch circuit breaker is all that it needs.

Some of them seem to derive their power from the outdoor unit and to operate at 240 volts, and some are wired independently. I'm hoping to sit down with some manufacturer's reps to find out more. I've read a couple of installation manuals, and they read like poor google translations into English. The one for Fujitsu shows an illustration without a disconnect and another with a disconnect, and has very ambiguous instructions.

Until we have a more definitive answer, we are going to be asking installers to provide us with the installation instructions and attempt to follow what we think those are saying...

Thanks

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I don't see why a requirement for a disconnect on an indoor section should be dependent on whether it belongs to a centrally ducted system or a ductless minisplit.

If a manufacturer of either type of system doesn't have a disconnect that integral to the appliance, an external one should be added.

Some minisplits have electric heat. If it catches fire, power needs to be removed without delay.

Marc

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I think Jim is referring to the common range hood / microwave combination that is allowed to be cord & plug connected if on an individual circuit per 422.16(B)(4). In high-end kitchens we don't see these as often as the independent hard-wired range hood.

Marc has convinced me with the comment about how some of these indoor units include resistance heat. We have concluded that the best way to achieve consistency within our department is to always require a local disconnect. This will comply with our mechanical code as well as the broadest interpretation of 440.14.

Thanks all

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I installed one in my garage this past summer (el cheapo unit from Amazon) and my instructions did not call for a disconnect inside, nor did I install one. All low voltage from the outside unit control panel. 3 maybe 4 wires if I recall correctly.

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I installed one in my garage this past summer (el cheapo unit from Amazon) and my instructions did not call for a disconnect inside, nor did I install one. All low voltage from the outside unit control panel. 3 maybe 4 wires if I recall correctly.

How low is the low voltage?

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