Can I use existing 220v for minisplit?


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Old 06-01-23, 09:14 PM
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Can I use existing 220v for minisplit?

going to hire a contractor, but trying to understand the options first...
I want to add a minisplit heatpump to one room in the house that gets too hot from computers/servers/office.

My breaker box is on the complete opposite side of the house, no crawl space. 2-story house (with small attic)

Is it possible/to code to permit using one of my 220v heat pump wiring and swap it to a junction box and then have two disconnect boxes, one to the 3ton heat pump, and one to a (new) .75tn mini split??

The 220v version says ~6 amps max (small unit)...I imagine my newer 18 seer heat pump doesnt use as much amperage as the old one 11 seer one, so the existing wiring should handle the amps of both running at the same time, but I dont know if thats against code and not an option?

Seeing if theres anyway I can accomplish my goal without having to run a completely new wire from the other side of the house which would be ugly attached to the wall.

Thanks
 
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Old 06-01-23, 09:37 PM
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Is it possible/to code to permit using one of my 220v heat pump wiring
Are you trying to use wiring for your whole house central AC unit?
Unless your AC unit was wired using oversize wiring. I don't think you can do it. Usually they are wired in 10AWG cable and maximum breaker size on that is 30A. Mose AC/heat pump units require 25A minimum. You will end up tripping breaker when both units are run.
If you have 8AWG and your heat pump requires much less current, then you could install a small subpanel with 2 breakers. I think this subpanel should be also qualified as service disconnect at the same time.

 
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Old 06-01-23, 09:50 PM
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Right thats what I was curious on.

The Trane 3tn heat pump sticker says 20amp minimum circuit if that helps?
Does that mean it might work if I did the small subpanel and made a separate breaker for each?
 
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Old 06-02-23, 02:53 PM
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Depending on the size of the existing cable you might be able to do the small sub-panel route. What size wire and what size breaker is feeding your existing heat pump?
 
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Old 06-03-23, 06:20 AM
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It is a 30amp breaker at the breaker box.

Here is a photo of the existing wiring. Is my wiring 10/2?
Also the mini-split has a neutral wire...any issues with the fact I dont have a white wire coming from the breaker box?

 
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Old 06-03-23, 12:09 PM
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Also the mini-split has a neutral wire...any issues with the fact I dont have a white wire coming from the breaker box?
Yes, that is not going to work if the mini-split requires a neutral. You will need to run a new circuit for the mini split or replace the 10/2 cable with a larger 3 wire plus ground cable to feed a sub panel.

Also, you should replace that A/C disconnect as it does not provide any disconnecting means.
 
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Old 06-03-23, 01:05 PM
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Oh I pulled the fuse out in that panel for the photo.
sounds like it needs a new wire regardless, ok thanks I’ll call some contractors and get that figured out.

EDIT: actually I was wrong, the 110v needs a neutral, 220v doesnt appear to need
 

Last edited by ps2cho; 06-03-23 at 02:18 PM.
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Old 06-03-23, 03:42 PM
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The fuse you pulled out was doing nothing. The power in and out are directly connected together via the wirenuts. The lugs for using the fuse are laying in the bottom of the box.
 
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Old 06-03-23, 06:52 PM
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Oh jeez I just realized what you said. I just had those heat pumps replaced a few months ago, no idea why those idiots have done thisÖ
 
 

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