# Mini Split AC Hook Up



## skymaga (Mar 14, 2014)

I have a few questions about hooking up a mini split AC unit (condensor sits outside and evaporator hangs on living room wall). Here are the spec for it:

12,000 BTU w/ Heat Pump
Power Supply: 115V/60Hz
Rated Current - Cooling - 13 amps
Rated Current - Heating - 14.5 amps
Cooling Capacity - 12,000 BTU
Heating Capacity - 11,700 BTU
MCA (Amps) 12.2
MCOP (Amps) 25

Wire Size / # Wires AWG16/4 
(I believe this refers to connecting the Condensor that is outside to the Evaporator that is inside)

I hooked up the evaporater via 14-4 AWG 600-volt mini split cable ( specifically made for this application).

I ran a 14 guage from fuse box to a 30amp fusable disconnect, and 14 guage from disconnect to condesnor. 

Fuse box at main panel has a 15amps (AC motor specific delay) fuse (there is nothing else hooked up to it besides this mini split) 

30amp 120/240V AC Disconnect, I only hooked up the hot wire using one side of the disconnect, used a 15amp fuse there, and connected the neutral together via a cap/electrical tape.

All electrical wiring is in conduit. 20 feet from panel box to AC disconnect, 20 feet from condensor to evaporator.

Any thoughts? Thanks in advance.


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## skymaga (Mar 14, 2014)

*Min Ampacity*

Also on the condensor outside, it says that minimum ampacity is 15amps, max breaker size is 25amps.

It has been running for about a week now with heat pump on without any noticable issues. Had amperage tested on cool mode, it was drawing around 5.5-6amps on high speed (condensor and evaporator combined), lowest cooling setting.


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## brric (Mar 5, 2010)

Sounds ok, you could go up to as high as 25 amps on the breaker.


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## skymaga (Mar 14, 2014)

brric said:


> Sounds ok, you could go up to as high as 25 amps on the breaker.


So if 15amp fuse is too low and it gets burned out, can I use a 25amp fuse and stay on the 14 guauge between main panel and condensor?


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## jbfan (Jul 1, 2004)

skymaga said:


> So if 15amp fuse is too low and it gets burned out, can I use a 25amp fuse and stay on the 14 guauge between main panel and condensor?


Yes. You can go as high as 25 amps.


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## TarheelTerp (Jan 6, 2009)

skymaga said:


> So if 15amp fuse is too low and it gets burned out, can I use a 25amp fuse and stay on the 14 gauge between main panel and condensor?


still won't hurt a bit to use a heavier wire and often will help
to use #12 (vs 14) or to use #10 (vs 12)


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## skymaga (Mar 14, 2014)

TarheelTerp said:


> still won't hurt a bit to use a heavier wire and often will help
> to use #12 (vs 14) or to use #10 (vs 12)


 
At this point, since I already ran the wire, and it's working fine with the 15amp fuse, would you re-wire to 12 guage? What are the benefits?

The wire is on the fuses, one in the disconnect, and another one at the main fuse box.


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## jbfan (Jul 1, 2004)

skymaga said:


> At this point, since I already ran the wire, and it's working fine with the 15amp fuse, would you re-wire to 12 guage? What are the benefits?
> 
> The wire is on the fuses, one in the disconnect, and another one at the main fuse box.


No need to change the wire.
#14 is fine with this install.


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## skymaga (Mar 14, 2014)

As far as the 30amp 120/220V AC Disconnect, it has two Line In and two Load In plus two screws for grounding, currently I'm only using one side of it, with running the Hot wire into Line In and running hot wire from LOAD IN to the condenser. I have the white neutral capped together and taped. I have a 15amp fuse on the pull out. 

Is this the correct way to do it?

Can I put another 15amp fuse on the other side and run the white neutral threw LINE IN / LOAD IN? I would prefer for it to be screwed into place instead of being capped/taped.


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## rjniles (Feb 5, 2007)

There is no reason to use a fused disconnect in this application. Using a 15 amp inthe disconnect defeats the purpose of using a 25 amp breaker/fuse in tbe panel.


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## skymaga (Mar 14, 2014)

I'm currently using a 15amp at fuse box and 15amp at disconnect. If the fuse on disconnect keeps popping or at fuse box keeps popping, then I will upgrade to a 20amp on both fuse box and disconnect. Right now it's fine on 15amps. I already had a fused disconnect so I used it instead of buying a new one that's not fuseable.

Any thoughts on hookup up the neutral at the disconnect?


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## jbfan (Jul 1, 2004)

skymaga said:


> I'm currently using a 15amp at fuse box and 15amp at disconnect. If the fuse on disconnect keeps popping or at fuse box keeps popping, then I will upgrade to a 20amp on both fuse box and disconnect. Right now it's fine on 15amps. I already had a fused disconnect so I used it instead of buying a new one that's not fuseable.
> 
> Any thoughts on hookup up the neutral at the disconnect?


Do not connect the neutral to the disconnect.


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## skymaga (Mar 14, 2014)

jbfan said:


> Do not connect the neutral to the disconnect.


sounds good, I'll leave the hot black wire in the disconnect and neutral going directly from fuse box to condenser.

thanks for everyone's input.


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## stickboy1375 (Apr 28, 2012)

Just to be a pain in the ass in this thread, if you used a cable between the outdoor unit and the indoor unit, that is a code violation, most of these split units come from other countries, you need to use a chapter 3 wiring method in the US.

I see this all the time, I just purchase 14-3 UF for these installs, and throw the cable away.


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## skymaga (Mar 14, 2014)

stickboy1375 said:


> Just to be a pain in the ass in this thread, if you used a cable between the outdoor unit and the indoor unit, that is a code violation, most of these split units come from other countries, you need to use a chapter 3 wiring method in the US.
> 
> I see this all the time, I just purchase 14-3 UF for these installs, and throw the cable away.


 

I'm not familiar with what chapter 3 method is. Can you elaborate? I used a the cable described above, came together with a 25ft lineset, sold seperately by home depot from the unit.


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## skymaga (Mar 14, 2014)

I hooked up the evaporater to condensor via 14-4 AWG 600-volt mini split cable ( specifically made for this application according to Home Depot).


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## stickboy1375 (Apr 28, 2012)

skymaga said:


> I hooked up the evaporater to condensor via 14-4 AWG 600-volt mini split cable ( specifically made for this application according to Home Depot).


 Doesn't matter who made the cable, it doesn't meet code, UF cable is the best solution to this, or car flex. Cable isn't allowed to be run through wall cavities... As I previously said, these units are made in other counties where cable is the norm, but in the US, it is a code violation. Also, I'm not giving you a hard time, but was your install inspected? Did you pull a permit?


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## mpoulton (Jul 23, 2009)

What, exactly is meant by "cable"? Stickboy, NM cable and UF cable are Chapter 3 wiring methods and work fine but they are called cables. What's non-compliant is some kind of flexible CORD that's not a Chapter 3 method. Skymaga, what is the 14-4 cable like? What does it say on it?


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## stickboy1375 (Apr 28, 2012)

mpoulton said:


> What, exactly is meant by "cable"? Stickboy, NM cable and UF cable are Chapter 3 wiring methods and work fine but they are called cables. What's non-compliant is some kind of flexible CORD that's not a Chapter 3 method. Skymaga, what is the 14-4 cable like? What does it say on it?


 It's a cord, I've seen these a million times, at any rate NM wouldn't fly either because it is run exterior. As a side note, they are installed with this cable all the time, I'm not saying your house will burn down, just that it violates the NEC.

Most times these are not inspected not permits pulled, this is why they are installed wrongly, plus most inspectors in my area are uneducated.


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## skymaga (Mar 14, 2014)

stickboy1375 said:


> It's a cord, I've seen these a million times, at any rate NM wouldn't fly either because it is run exterior. As a side note, they are installed with this cable all the time, I'm not saying your house will burn down, just that it violates the NEC.
> 
> Most times these are not inspected not permits pulled, this is why they are installed wrongly, plus most inspectors in my area are uneducated.


The cable is 14 guage with 5 different colors. I ran it in a whip from outside into garage and then through the living room wall.

It looks like a standard cable that central AC would use between condenser and air handler and then air handler and thermostat except that it's 14 guage.


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## stickboy1375 (Apr 28, 2012)

Still doesn't meet chapter 3 wiring method


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## skymaga (Mar 14, 2014)

stickboy1375 said:


> Still doesn't meet chapter 3 wiring method


Hmmm... so all these central A/Cs that are hooked up this way don't meet the code? I had central air swapped on our rental unit and it pasted inspection without having to rewire the cable that ran from condenser to air handler. Is that different?

Can you describe in detail how I need to rectify this situation to be up to code?

Thanks in advance.


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## stickboy1375 (Apr 28, 2012)

skymaga said:


> Hmmm... so all these central A/Cs that are hooked up this way don't meet the code? I had central air swapped on our rental unit and it pasted inspection without having to rewire the cable that ran from condenser to air handler. Is that different?
> 
> Can you describe in detail how I need to rectify this situation to be up to code?
> 
> Thanks in advance.


I really wouldn't waste your time, this install is done all the time, this is what happens when a product is brought in from another country, if you really feel the need to change the wiring, I would just use UF type cable.


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## WyrTwister (Jul 22, 2013)

skymaga said:


> As far as the 30amp 120/220V AC Disconnect, it has two Line In and two Load In plus two screws for grounding, currently I'm only using one side of it, with running the Hot wire into Line In and running hot wire from LOAD IN to the condenser. I have the white neutral capped together and taped. I have a 15amp fuse on the pull out.
> 
> Is this the correct way to do it?
> 
> Can I put another 15amp fuse on the other side and run the white neutral threw LINE IN / LOAD IN? I would prefer for it to be screwed into place instead of being capped/taped.


 No , you do not fuse a neutral .

God bless
Wyr


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## WyrTwister (Jul 22, 2013)

stickboy1375 said:


> Still doesn't meet chapter 3 wiring method


 I installed a 12,000 btu mini split A/C - Heat pump this last summer . I used 14/4 plenum cable between the outside & the inside unit . This is low voltage , like thermostat cable installation . 

There is nothing in the inside unit but electronics , a tiny fan motor and a servo motor to operate the louvers . Pretty sure , digital communications between the inside & the outside .

Chapter 3 wiring methods are a non issue . The power connects to the outside unit .

Mine is on a 15 amp SP CB & 14/2 W/G Romex . I have a no-fuse pull disconnect on the outside , at the unit .

This is not rocket science . And the wiring is the simplest part of the install .

God bless
Wyr


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## stickboy1375 (Apr 28, 2012)

WyrTwister said:


> I installed a 12,000 btu mini split A/C - Heat pump this last summer . I used 14/4 plenum cable between the outside & the inside unit . This is low voltage , like thermostat cable installation .
> 
> There is nothing in the inside unit but electronics , a tiny fan motor and a servo motor to operate the louvers . Pretty sure , digital communications between the inside & the outside .
> 
> ...



You are sending 240v to the indoor unit, and a communication conductor, you also need a disconnect at the indoor unit as well.











Typical wiring diagram, as you can see, two disconnects are required... so simple you installed yours incorrectly and non code compliant, sometimes I think this is rocket science for some people.


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## skymaga (Mar 14, 2014)

WyrTwister said:


> I installed a 12,000 btu mini split A/C - Heat pump this last summer . I used 14/4 plenum cable between the outside & the inside unit . This is low voltage , like thermostat cable installation .
> 
> There is nothing in the inside unit but electronics , a tiny fan motor and a servo motor to operate the louvers . Pretty sure , digital communications between the inside & the outside .
> 
> ...



Mine is pretty much same, except in those plastic like whips. It's working great, and with 15amp fuses both at disconnect and at fuse box, I feel pretty safe. I also have 12 smoke / heat detectors throughout, including garage, some are hooked up to fire monitoring.

I was in a house fire at a rental few years back, so I'm a little paranoid. 


Thanks for everyone that has contributed to this post.


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## skymaga (Mar 14, 2014)

stickboy1375 said:


> You are sending 240v to the indoor unit, and a communication conductor, you also need a disconnect at the indoor unit as well.
> 
> 
> 
> ...


How would he send 240v to the indoor unit? Mine 12BTU runs on 120v.


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## stickboy1375 (Apr 28, 2012)

skymaga said:


> How would he send 240v to the indoor unit? Mine 12BTU runs on 120v.


I've never seen a 120v unit, but i'm sure they exist.


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## WyrTwister (Jul 22, 2013)

Mine is 120 VAC . To the condenser unit .

And the control cable for mine is low voltage .

http://s719.photobucket.com/user/Wy...sor07-08-2013_zpsaf78ed8f.jpg.html?sort=3&o=2

God bless
Wyr


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## carmusic (Oct 11, 2011)

i also have a 120v unit, indoor part is at 32v! :laughing:


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## stickboy1375 (Apr 28, 2012)

carmusic said:


> i also have a 120v unit, indoor part is at 32v! :laughing:


And what is your point? You still have to follow the NEC. :whistling2:


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## WyrTwister (Jul 22, 2013)

No matter what the schematic that you came up with says , many / most of ours are low voltage between the inside & outside unit . Same as tstat wiring between a furnace and a tstat .

I do not know what is SOP in your location , tstat cable is run " wild " here . And , evidently , other places , too ?

God bless
Wyr


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## stickboy1375 (Apr 28, 2012)

WyrTwister said:


> No matter what the schematic that you came up with says , many / most of ours are low voltage between the inside & outside unit . Same as tstat wiring between a furnace and a tstat . I do not know what is SOP in your location , tstat cable is run " wild " here . And , evidently , other places , too ? God bless Wyr


 I'm betting they are not low voltage, I'm betting you are mis reading the schematic, and by the looks of your unit, you are mis informed.


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## WyrTwister (Jul 22, 2013)

Well , I got off the sofa and my lazy behind . Went out to the truck and got my Fluke & a screwdriver . Got up on a chair & proceeded to check the voltage , at the terminal strip , where the interconnecting plenum cable is terminated at the inside unit .

Different terminals yielded different voltage between them . The first 2 are probably the low voltage " power " I got 29 - 32 volts . Did not bother to notice if it was AC or DC , I did not really care . The other readings were less than that to zero . 

We use that particular plenum cable , 2 pair T/S cable for energy management . Brought about 25' from work . Seems to work fine .

There is nothing more that I can think to add ?

God bless
Wyr


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## stickboy1375 (Apr 28, 2012)

WyrTwister said:


> Well , I got off the sofa and my lazy behind . Went out to the truck and got my Fluke & a screwdriver . Got up on a chair & proceeded to check the voltage , at the terminal strip , where the interconnecting plenum cable is terminated at the inside unit . Different terminals yielded different voltage between them . The first 2 are probably the low voltage " power " I got 29 - 32 volts . Did not bother to notice if it was AC or DC , I did not really care . The other readings were less than that to zero . We use that particular plenum cable , 2 pair T/S cable for energy management . Brought about 25' from work . Seems to work fine . There is nothing more that I can think to add ? God bless Wyr


And? What's your point?


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## WyrTwister (Jul 22, 2013)

Mine is low voltage . Many / most of these units are . " 

Low voltage " cable is fine . ( Although , I think the cable I used is rated for 300 volts ? )

My 120 VAC is run in Romex . Where it exits the vertical " cover " , it is inside LiquidTite flex . To the pull no-fuse disconnect and from there to the condenser . 

As is the plenum cable , in a separate flex .

Have a fine day .

God bless
Wyr


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## rjniles (Feb 5, 2007)

WyrTwister said:


> Mine is low voltage . Many / most of these units are . "
> 
> Low voltage " cable is fine . ( Although , I think the cable I used is rated for 300 volts ? )
> 
> ...


NMB in Sealtite in a wet or damp location is non compliant.


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