Mini-Split Electrical Help

Old 05-13-18, 06:28 PM
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Mini-Split Electrical Help

Hi, I'm from the Northeast and I recently just purchased a multi-zone ductless mini split system and am trying to run the electrical for it. Only the hvac portion is being installed by a professional. I have space on my panel for a 30 amp breaker, I am just looking for some clarification since I'm being told multiple different gauges to run the electrical from the panel to the outside shutoff box, and then again from the outdoor unit to the two heads. Below is all the information on the two heads and outside condenser, any help would be appreciated. Thank you.

18k BTU mini-split heat pump
12k BTU head
9k BTU head

power supply 230v 60
minimum amp 18
max 25 (was going to use a 30)

in/outdoor connect cable - 16/4 (Confused since some recommendations from hvac professionals said 14/4..)
panel to shutoff box - (Was told 12/3 would be sufficient?)

Actual purchase:

Pretty much the only paperwork delivered with it....

Any thoughts or advice would be great. Thanks again.
Old 05-13-18, 08:24 PM
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16 gauge wire is some thin stuff. Is this only for the indoor fan or are you going to try running a compressor with this skinny wire?
Old 05-14-18, 02:30 AM
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I feel your confusion. Mini's are the unwanted stepchild of the AC business and there is not a lot of solid info available.

When I ordered my first mini a 12k btu Daikin and lineset it came with 16/4 SOOW/SJOW, basically an extension cord. The reasoning being that it is part of the unit and does not come under code. Is not supplied by manufacturer so not exactly right..

Daikin install manual recommends 16/4 under 33 feet and 14/4 over 33 feet between units.

By the time I got to my second unit I asked electricians and they prefer 14/4 tray cable. So I used 14/4 Tray cable on 2nd unit. There are millions of these installed with 16/4 so I am not concerned about the first one and it is under 33 feet.

I am not qualified on the electric, I can tell you a 30amp breaker on 12 Gage wire is a BIG NO NO! The breaker/fuse protects the wire and 10 gauge wire would be minimum with 30amp .

There must be a sticker on the outside unit saying the amps needed, get that info and go ask on the electrical forum, for the proper info.
Old 05-14-18, 02:48 AM
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Also it is claimed that mini's do not like line surges so I added a whole house surge protector.
Old 05-14-18, 01:35 PM
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14/4 for the indoor units. How far from your panel box to the unit is it? If you use a 30 amp breaker and #10 wire you will need to have a fused disconnect at 25 amps.
Old 05-14-18, 05:28 PM
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Airman is correct. Since that cable is carrying at least 120vac to the inside heads.... it needs to be at least 14/4. 16/4 is not listed for high voltage use.

Most of the splits I've installed required 3 wire cable so I use 14/3 UF w/ground.
Old 05-14-18, 06:21 PM
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I thought the indoor head was DC on the inverter models? I glanced at the manual but it is 400 pages so I do not want to read it all.

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