Mini Split AC Install

[jhort]

Hello all. Wanting to install Gree mini split 12000 btus 220 volts. Wire run has been done already from breaker panel to outside wall near where exterior unit will be placed. I believe wire is 10/2 with ground. It's yellow sheath.

The wire comes down the wall in a conduit from attic and ends in a junction box. The wire enters the box in the conduit from the top. The box though is solid. No knock out holes. Has a front cover with 4 screws. Inside the box, the 10/2 is just coiled up inside. There is nothing in this box to connect anything.

Is this a temporary box? I was expecting a box with knock out holes to wire up the whip that goes to condenser. Also, if another box is needed, my search for a box does not yield any boxes that have an opening at the top so that wire can be fed through there. I wish i could post pics.

Any ideas, suggestions, advise, comments appreciated. Thanks

 

[mike93lx]

That is #12, not #10. It is also NM-b, which is not allowed outside.

You need a disconnect, so another box is needed

Where are you located? Are you really comfortable with doing electrical work?

 

[Syberia]

If there are no holes then you can drill your own, however the previous poster is correct. Wire type is incorrect and you're probably better off replacing the box with an AC disconnect or 2-pole switch.

 

[jhort]

Hello. I am not an expert but have done some electrical work. Just not with installing mini split. Im in California. I feel comfortable enough with some guidance. I am not rushing and am very patient following directions and putting safety first. Any suggestions on type of disconnect box i can get. I can't find any that feeds from top.

Can wires be simply redirected to enter a box from the side or bottom? Seems typically where knock out holes are in boxes I have seen. It would be so much easier to get a box with opening on top. Also, what will this box need to have inside so that these 12 gauge wires can be connected as well as the whip coming out ? The whip i got has 10 gauge wire in it. Probably won't work then? posted a pic of the whip I have. Is this correct whip? And the box.? Thanks so much!

 

[jhort]

Sorry. Pics didnt upload.

 

[mike93lx]

You need to remove the wiring and replace it with something rated for outdoor use, like THWN.

When you do that, it would be best to remove the existing box and have the conduit run directly into the new disconnect

 

[Git]

Yes, I would say that is just a temporary box

Just get a disconnect with a whip and replace that box - they sell them as kits, or you should be able to piece something together at Lowes/Home Depot. I got mine from eComfort when I ordered my Mr Slim

Not an electrician, but I thought you were able to run Romex in a conduit for a short length?

 

[mike93lx]

Yes, I would say that is just a temporary box

Just get a disconnect with a whip and replace that box - they sell them as kits, or you should be able to piece something together at Lowes/Home Depot. I got mine from eComfort when I ordered my Mr Slim

Not an electrician, but I thought you were able to run Romex in a conduit for a short length?

Conduit isn't the problem.

Outdoors is

 

[jhort]

Thanks guys. Did just that. Pieced together at home depot. Got empty whip and individual 12/2 wire, black, white, green that i will slip through whip. As for disconnect nox i got a 30 amp. AC guy told me is what i needed since mini split is one ton. The box is GE brand and has 3 knock outs. I'm just going to inmstall it sideways so opening is facing up where conduit is coming from then use other two knock outs to run whip out. What do you all think?

 

[Bert_]

Thanks guys. Did just that. Pieced together at home depot. Got empty whip and individual 12/2 wire, black, white, green that i will slip through whip. As for disconnect nox i got a 30 amp. AC guy told me is what i needed since mini split is one ton. The box is GE brand and has 3 knock outs. I'm just going to inmstall it sideways so opening is facing up where conduit is coming from then use other two knock outs to run whip out. What do you all think?

Don't mount the disconnect sideways. The drain holes in the bottom will become "fill" holes. Just put an lb on the existing conduit and go into the side of the new disconnect.

The wire in the outside conduit can be argued. My opinion is it's fine. A piece of vertical conduit like that can never accumulate any water.

 

[mike93lx]

It's fine until it gets inspected, but either way it isn't my house

 

[jhort]

Thanks. There is actually inspection pending so will know then. And I'm sorry, but what is an lb? Some kind of an adapter?

Attached is the inside pic of 30 amp disconnect box. From top left to right nuts reads "line , load, load, line. Then there are bottom nuts. This is where i really want to take my time and ensure i get connections right. Need some guidance where each wire goes coming from conduit as well as the wires leaving box through whip. I have black, white, green coming from breaker and black, white, green in whip.

Also, the unit came with two sets of control/communication wires to connect interior unit to exterior unit. From all videos i have seen, i only noticed one set. Is this just an extra or am i missing something? Thanks in advance!

 

[LS6 Tommy]

Deleted post made by mistake...

 

[56Mark]

An LB is basically an elbow that has a sealed cover you can remove to help you feed the wires through. Can get at any big box or electrical supply place.

Line -Load - Line = Put the incoming 12 ga wires on the outside terminals, this is the line. Put the whip wires to your Load (minisplit) on the inside terminals. So, left to right; Black incoming - Black wire in whip to mini - White wire in whip to mini - White incoming. When you pull out the disconnect with the copper blades it breaks these connections. Make sure your ground wires are connected to the lower ground lugs, the bottom nuts (very important to keep you from becoming a crispy critter). If you are not sure, get some help!

 

[jhort]

Ok. Much appreciated

 

[SlappyWhite]

Can they do rear entry through the wall directly into a disconnect box with the NMSC under NEC/etc.?

 

[Syberia]

Use this or this to come into your disconnect box from the side.

 

[metlmunchr]

also, the unit came with two sets of control/communication wires to connect interior unit to exterior unit. From all videos i have seen, i only noticed one set. Is this just an extra or am i missing something? Thanks in advance!

IIRC, both my units have 5 conductor comm cables. What you have could be an extra, or it could be something like a 3 wire and a 2 wire. Just have to look at the installation instructions to verify the comm wiring and compare to what was supplied to know for sure.

 

[jhort]

Got it thanks. I guess they could have done rear entry through wall but didn't. Went through attic and came down the wall.

Can someone confirm if the 12 gauge is thick enough for this 230V mini split? Also, the 30 amp disconnect box is good enough for one ton unit? Just want to confirm. Thanks

 

[Jakemedic]

12 gauge wire is only good for 20 amps. 10 gauge for 30 amp. Hope that helps you!

 

[Bert_]

12 gauge wire is only good for 20 amps. 10 gauge for 30 amp. Hope that helps you!

It's important to note that this is true when talking about the running current but the breaker size can and often is larger when it comes to anything with a motor.

 

[56Mark]

Got it thanks. I guess they could have done rear entry through wall but didn't. Went through attic and came down the wall.

Can someone confirm if the 12 gauge is thick enough for this 230V mini split? Also, the 30 amp disconnect box is good enough for one ton unit? Just want to confirm. Thanks

Unless you have some auxiliary heat or something unusual, yes 12 ga is good for a one ton mini, 240V or 120V. Amperage should be pretty low if you have a 240V unit. Amp draw should be in the manual.

 

[jhort]

Thanks all. I had checked but will double check to be sure.

 

[jhort]

While i get home and look for manual, does this say anything with regards to amps? Also, the disconnect box is fused and was told i could install 20 amp fuses though it's for 30 amp. Was i told correct? Thanks

 

[SlappyWhite]

12,000 BTU/h is mathematically ~15 amps at 240 VAC and ~30 amps at 120 VAC. That is without any losses factored in.... or any start-up factors.

 

[Bert_]

12,000 BTU/h is mathematically ~15 amps at 240 VAC and ~30 amps at 120 VAC. That is without any losses factored in.... or any start-up factors.

That's way too high. My 18,000 btu window unit is like 9 or 9.5A on 240v

 

[Bert_]

While i get home and look for manual, does this say anything with regards to amps? Also, the disconnect box is fused and was told i could install 20 amp fuses though it's for 30 amp. Was i told correct? Thanks

I would say max of 15A for that unit. I think 4.5A is the running current.

 

[mike93lx]

12,000 BTU/h is mathematically ~15 amps at 240 VAC and ~30 amps at 120 VAC. That is without any losses factored in.... or any start-up factors.

My 2 ton mini was something like 7a 240 and window units are commonly available at 12k btu on 120v

How are you calculating that?

 

[Syberia]

12,000 BTU/h is mathematically ~15 amps at 240 VAC and ~30 amps at 120 VAC. That is without any losses factored in.... or any start-up factors.

That's for resistive heat. Heat pumps are "more than" 100% efficient so those numbers aren't relevant.

From the label that OP posted, it looks like the unit draws 4.5 amps at 240 volts. #12 wire will be just fine.

 

[jhort]

Awesome. Thanks. I Went and got electrical elbow. But shoud it have threads or something to attach to box.

 

[Bert_]

Awesome. Thanks. I Went and got electrical elbow. But shoud it have threads or something to attach to box.

Need a box connector.

 

[Syberia]

Raintight compression fitting

 

[Yankeefarmer]

12,000 BTU/h is mathematically ~15 amps at 240 VAC and ~30 amps at 120 VAC. That is without any losses factored in.... or any start-up factors.

Your numbers assume a COP of 1. Heat pumps/AC are much more efficient than that.

 

[jhort]

Thanks think i got what i need.

So I'm at the point of drilling hole in the inside of wall where piping, drain tube and unit wires will be exiting. I tried drilling pilot hole first before going in with hole saw. The drill bit went through dry wall but soon as it fot through it hit stud, or joist i don't know. Not going through that very easily so i stopped.

Would hole saw go through what ever is in there? I know its not metal or wires. It's wood alright. Any advice appreciated. Thanks

 

[56Mark]

move the hole over 1 1/2" or so? Use a stud finder to see where the studs are first. Best to avoid cutting a stud into.

 

[jhort]

Well it wasn't studs. Actually just more dry wall but harder had wire inbedded. Got the hole done. Ready to mount unit on bracket. Just have to bend ac lines a bit so they exit out the hole but don't want to kink them.

 

[jhort]

I'm at point of connecting unit wires. I noticed that one set has three wires and the other set has four. See pics. Could it be that the one with three is the one to be used through whip. That is the wiring that will go from disconnect box to condenser unit?

 

[jhort]

Here pics

 

[jhort]

Also....I thought this would be simpler but; that 14-4 cable include wires green/yellow which i can pretty much deduce is ground, a blue, which almost looks aqua blue, a light gray and a black, which you can also say it's dark brown. Except for ground, i don't know where others go for interior unit. See pic.

Also, I looked at exterior unit and prewiring is as follows: from left to right n1 is blue wire. This blue looks like actual blue. Next is black (2). Also actually looks black. Then it's actual looking brown (3). Lastly of course rhe ground symbol. I know i need to probably match interior unit wiring but can't really distinguish colors. Any guidance please much appreciated. I am tempted to go with closest color matching but don't want to chance it. Thanks

 

[metlmunchr]

The gree installation manual shows N1, 2, 3, and ground, and also indicates the indoor unit terminals are marked same as outdoor unit. Regardless of color, a given wire needs to hook to the same numbered terminal on both units. Are you saying the terminals on the outdoor unit aren't marked?