Ductless split unit service switch

[Sfm15]

I am installing ductless units for heating and cooling. I have to put a service switch for them per the inspector. Do I only have to switch the 240 or do I also have to switch the communication wire? Do I have to switch the 220 only or do i have to put a 3 pole switch in and switch the communication wire as well? Thank you in advance.

 

[kwired]

Questions about this come up pretty often here, and there seems to be a lot of variance in the answers as well.

One thing to consider - the indoor unit does not contain a hermatic refrigerant compressor, therefore art 440 does not apply to it.

That leaves it covered by art 422. Most of these are basically just a small blower and some controls. Art 422.31(A) allows the branch circuit overcurrent device to be the disconnecting means if not over 300 VA or 1/8 HP, if over 1/8 HP then 422.31(C) will require a disconnecting means within sight of the appliance. I still can't tell you if you do need a local disconnect if it must open the control lead or not.

 

[GoldDigger]

The mini-split units I am familiar with put a signal on the control wire which is an offset voltage from one of the (240V) line conductors. It is not a low voltage line and must be interrupted by any safety disconnect. You can use a three pole snap switch if you can find one.

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[Ponchik]

The mini-split units I am familiar with put a signal on the control wire which is an offset voltage from one of the (240V) line conductors. It is not a low voltage line and must be interrupted by any safety disconnect. You can use a three pole snap switch if you can find one.

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Once you turn off the local disconnect for the main unit does it turn OFF the control and power circuit for the indoor units?
I think it does.
Or it may vary from system to system.

 

[GoldDigger]

Once you turn off the local disconnect for the main unit does it turn OFF the control and power circuit for the indoor units?
I think it does.
Or it may vary from system to system.

It should, but some inspectors want to see a separate in-sight disconnect for the indoor unit. (i.e. since the outdoor disconnect is on the other side of the wall.)

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[macmikeman]

Here is how to do it using a double pole switch (cheaper than a 3 pole) . Rope the feed for the compressor thru an interior switch box mounted near the interior fan coil unit, and then out to the compressor disconnect. Install a double pole in that switch box. Turning off the interior switch kills power to the outdoor unit, which in turn kills power to the fan coil, so ..... disconnecting means accomplished.

 

[mopowr steve]

Here is how to do it using a double pole switch (cheaper than a 3 pole) . Rope the feed for the compressor thru an interior switch box mounted near the interior fan coil unit, and then out to the compressor disconnect. Install a double pole in that switch box. Turning off the interior switch kills power to the outdoor unit, which in turn kills power to the fan coil, so ..... disconnecting means accomplished.

Great thinking!