Mini Split Indoor Unit Wiring

[magic_garage]

Hi All:

I just got a Mitsubishi 18k unit installed and I saw that the contractor used 14/3 romex (light blue) to wire the indoor unit to the outdoor unit. He ran the wire from the indoor unit with the linesets in Inaba lineset covers to the outdoor unit. The Inaba lineset cover ends on the wall behind the outdoor unit so there's about 2 feet of non-covered distance to the connection on the outdoor unit...typical setup. The contractor put the romex in liquid tight conduit for this last remaining length to the outdoor unit. They had the liquid tight conduit start a few inches in on the lineset cover before it ended, and terminate on the conduit mount on the outdoor unit, using the proper fitting. I initially thought the LT ran all the way to the indoor unit.

Anyway, my question is, is it to code to use romex for the indoor unit? I was looking at the info tag on the indoor unit and it seems to run off 208/230V, unless the voltage was meant for the outdoor unit. So shouldn't the indoor unit follow NEC for the wiring? If it should follow NEC, then the installers should use UF cable in the lineset cover, or run the wire separately in electrical conduit? Or use THHN in the LT conduit in the lineset covers? I'm confused.



Thanks!

 

[PCustoms]

Post a pic, with any writing on the jacket you can see.

I'm curious about blue romex, never seen it. I suspect your looking at control cable.

 

[magic_garage]

Sorry I tried to read off anything from the cable and I can't see anything. I would need to get a lot more invasive in order to see more and being that I just got this installed, I don't want to risk mucking something up.

The color got my attention too but it's not like I know a lot about electrical work so I figured it was a new color I personally never seen. But I swear, I seen at least "NM" on the wrapping, and it's flat just like romex.

In any case, should the indoor unit get treated like any typical AC powered device that's being hardwired so the wiring portion should abide by NEC? Isn't the indoor unit control + power?

 

[southalabama]

CerroMax™ NM-B

Cerrowire offers blue and purple color coded wire, including 4/3 and 12/3 NM-B electrical wire, so you can tell the difference quickly.

www.cerrowire.com

 

[chinboys]

Overkill for the purpose of conducting 220v AC under 8 amps, a cooling signal, and ground.
Worst is the use of a solid conductor when stranded wire is sought to reduce potential vibration based work hardening of conductors.
We normally use 14/4 STR THHN 600v cabling to connect the indoor evaporator to its outdoor condenser unit.

 

[magic_garage]

CerroMax™ NM-B

Cerrowire offers blue and purple color coded wire, including 4/3 and 12/3 NM-B electrical wire, so you can tell the difference quickly.

www.cerrowire.com

Thanks for the confirmation.

 

[magic_garage]

Overkill for the purpose of conducting 220v AC under 8 amps, a cooling signal, and ground.
Worst is the use of a solid conductor when stranded wire is sought to reduce potential vibration based work hardening of conductors.
We normally use 14/4 STR THHN 600v cabling to connect the indoor evaporator to its outdoor condenser unit.

Good point on the solid/str cable. But I'm still confused on what is the right way to run the cable was well. So you use THHN, how exactly are you running the conduit for it? I'm assuming you have some covering for the linesets as well so how do you integrate both?

 

[4x4Pete]

I don't know for sure but would think that the wiring from the outdoor unit to the indoor unit would fall under a different law than normal residential service wiring. Almost like it's part of the appliance?

 

[rlitman]

No, that's not at all code compliant. UF would take care of the wet location issue, but would still need protection from damage for that jump from the wall to the unit. That's why most people nowadays use tray cable made for mini-split hookups.

That being said, if there's no way for water to wick up that NM, it's probably not too bad.

 

[pcmeiners]

"Worst is the use of a solid conductor when stranded wire is sought to reduce potential vibration based work hardening of conductors."

Your minisplits vibrate excessively? Let not get carried away

 

[SVibs]

But I'm still confused on what is the right way to run the cable...

I believe the correct cable for the application is four conductor "Tray Cable". It's rated for in-wall and conduit use. The SJOW cable that ships with most mini split line set "kits" is rated for neither. I was similarly confused about the wiring--you may find this post helpful.

 

[magic_garage]

I believe the correct cable for the application is four conductor "Tray Cable". It's rated for in-wall and conduit use. The SJOW cable that ships with most mini split line set "kits" is rated for neither. I was similarly confused about the wiring--you may find this post helpful.

That post was very helpful...thanks.

 

[pcmeiners]

This metal shielded cable will pass any inspection.​

EZ-in shielded Minisplit cable , 14-4​

https://www.supplyhouse.com/Southwire-59351203-EZ-IN-Shielded-Mini-Split-Cable-14-4-Stranded-600V-50?utm_source=google_ad&utm_medium=Shopping_withoutdata&utm_campaign=Shopping_Without_PLTV_data&gad_source=1&gclid=CjwKCAiA44OtBhAOEiwAj4gpOSzp0uwqis9eqrj2dIerfZ1Vqqq6790GIzf2hHaN50bhSZiJtJeD5BoCfQEQAvD_BwE