I'm installing a small minisplit for my garage. The garage is part of the house (front right corner of the house) and I have to put the minisplit condenser in the back of the house. My breaker panel is outside at the front right corner of the house. If I go straight through the back of the panel, I'm in the garage. I need to get power to the rear right corner of the house.

What I've come up with for options is the following..run pipe from the bottom of the panel down to the area where the slab and stucco meet. It varies between 6 and 8" off the ground. Then follow that down the side of the house to the back, make the turn to the back and run up to a disconnect where I need it. I would pull individual wires. Is there any issues running pipe like that?

The other option is to go into the garage, pipe it to where the lineset will be going up into the space between the first and second floor and follow the lineset out the back of the house. but this means the wire would partially be in pipe and partially be in a rafter space. That means I can't use individual wires. I'd have even more pipe in my finished garage. I'm also unclear the proper way to exit the building. When I exit I have to pipe it to the disconnect correct?

I'm in Phoenix, so no issues with snow. Thanks.

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  • Why not the same wall as the panel? Air conditioners don't need a south/west exposure, that's just Murphy's Law. May 21 at 17:16
  • @Harper-ReinstateMonica are you talking about the indoor unit or the condenser? The condenser has to go where it is because of the HOA and there is a narrow walkway on the side of the house and it would take up too much space. The indoor unit could be moved, but that affects the lineset length as well as where the lineset runs. Again I was trying to avoid any major changes to the outside of the house in front of the yard gate which is about halfway between the front and back.
    – Mike
    May 21 at 17:54

Since you are running your lineset inside run your power along with the line set. Conduit up the wall from the panel enter the house and change over to NM cable. Or run n conduit inside your choice. Run to the back wall. Most Electrician’s will use an LB conduit body to enter the home (and or exit). Run down to your disconnect with conduit.

To me that sounds like the cleanest install but you can run your conduit at the foundation. There is less chance of the conduit getting damaged up and inside schedule 40 pvc conduit inside would not be that hard to put in. Schedule 80 will be needed at the foundation level of using pvc. EMT can be used in both locations also. I prefer emt over pvc I think it is easier for sizes under 1” but that’s just an opinion many people use pvc. Note; You will probably need an expansion joint with pvc outside along the foundation.

  • I would likely run EMT too, but would caution a homeowner that he might find bending EMT and struggling with raintight EMT may prove to be difficult. May 21 at 16:18
  • @nosparksplease Since this will be a small split 1/2” emt will be more than enough (24000 btu feeder will fit in 1/2”) raintight is just a compression fitting verses a screw fitting I see no difference in install other than one uses a screwdriver the other a wrench.
    – Ed Beal
    May 21 at 16:27
  • I'd try to run EMT all the way inside. +1
    – JACK
    May 21 at 17:17

No problem running on the exterior, limit the added angles of bends to 360° or less between pull points. Use conduit bodies where tight bends are required. Penetrate cabinets at the bottom of cabinets or only where otherwise indicated as OK. Normally only the bottom couple inches of the sides allow entry.

Running through the garage as you propose creates a few issues if you run NM cable through conduit, the size of conduit, securing the cable to the cabinet, and re-entering a wet location.

Conduit fill for cables in conduit calculates the widest diameter of the cable assembly as a single round cable. The result is not too deadly for a small single NM cable, but if you need to run UF or an additional circuit for the required maintenance receptacle outlet your calculation bulks up quickly. Depending on age of the house your existing receptacle may be more than the now required 25' rule, your new unit must meet the current rule.

Securing to the cabinet can be confusing. The NEC treats cabinets (Article 312) and junction boxes (Article 314) differently. Generally (with a N/A 7 point exception) where cables enter a cabinet the cable has to be secured to the cabinet. The acceptable product list for doing this is short (or non-existent). There are work arounds, such as a short conduit out of your panelboard to an interior junction box, run THWN conductors to that J-box, then change to your cable assembly in the j-box. Edit: You can avoid the above fill issues and securing to the cabinet issue by splicing NM cable from joist space to individual wires in a j-box at the back of the garage.

When your penetration leaves the building you can't have NM-b in wet location, inside an exterior conduit is considered a wet location, so you need a box to convert back to THWN wire. Most AHJ''s will allow the NM to penetrate the wall directly into a j-box, I've heard rumors of some that require the change before exiting. You can use UF to overcome that, but UF is often flat, increasing the conduit fill calculation.

Yes you need a disconnect within sight of the AC unit. If you run through the building then down then to penetrate the top of a disconnect you would need a raintight hub using a tapered nipple in the hub, then a female adapter to PVC. Might be easier to extend down the side of the disconnect and enter the bottom edge of the side using a conduit body.

Fasteners to the building have to be adequate to securely hold to the wall, an inspector could go all UL on you. Your biggest issue really is building code preventing water damage.

  • Why is conduit required for the NM shown in the diagram (yellow)? Can’t NM run through the rear house wall directly into the back of the cutoff box that isn't shown in the diagram? And from that box via a watertight flexible PVC pigtail to the compressor?
    – jay613
    May 21 at 16:51
  • @jay613 It isn't required to be in conduit in the joist space. OP had already qualified that it wouldn't be in pipe, and I didn't oppose that. Only sounded to me like he would be using only NM, through the conduit in the garage. I will edit to make clear he can avoid fill issues by using THWN in conduit. Fishing down from joist space into disconnect may be an option. May 21 at 19:31

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