Mini-Split wire

[myhvacguy]

Good day all,
I was hoping to get some clarification from experts. Or, at least someone familiar enough with the 2017 NEC that can point me in the right direction. My company is currently working 2 different job sights (multi family residential apartments buildings) in the city and county of Denver, CO where we are installing LG mini splits in some common amenity areas. One of the electrical contractors is asking us to run the communication wire alongside out line set without any conduit. The other stated that this will not pass the electrical inspection and that it needs to be run separately and in conduit. This communication wire is a 14/3 that carriers 208VAC from the condenser to the head unit. Any help in this would be appreciated. From my understanding Denver follows NEC2017 for its electrical requirements.


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[Dennis Alwon]

I am not sure what communication wire is but when we installed these many years ago we used 14/3 nm cable. The 14/3 provided power and the red wire was the communication. I don't know how it is done today

 

[hbiss]

Usually use 14/3 UF for that. But that's in a simple residential setting. In your case whether or not you can use UF as opposed to conduit or some other wiring method, whether the UF can be ty-wrapped to the line set or not depends on other factors because this is multi-family and we don't know what the construction is.

It would be best to have the EC ask the inspector for a determination to settle this.

-Hal

 

[LarryFine]

If you're supplying 208v, that's power, not communication.

 

[myhvacguy]

I am not sure what communication wire is but when we installed these many years ago we used 14/3 nm cable. The 14/3 provided power and the red wire was the communication. I don't know how it is done today

Dennis,
That is pretty similar to what we are doing. I’m just wondering if it needs to be run in conduit or if it can be run along side the copper line set. Is there a NEC article I can reference?


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[electrofelon]

Most often I see type TC-ER used. It was always questionably legit. Can't remember if recent code cycles have clarified it's use. I know WA has an amendment allowing it.

 

[Dennis Alwon]

Tray cable is what the ac guys use but not sure why that over nm

Here is what 2-020 says about TC cale

Uses Permitted
(9)
In one- and two-family dwelling units, Type TC-ER-JP cable containing both power and control conductors shall be permitted for branch circuits and feeders. Type TC-ER-JP cable used as interior wiring shall be installed per the requirements of Part II of Article 334 and where installed as exterior wiring shall be installed per the requirements of Part II of Article 340.
Exception: Where used to connect a generator and associated equipment having terminals rated 75°C (140°F) or higher, the cable shall not be limited in ampacity by 334.80 or 340.80.
Informational Note: See 725.136 for limitations on Class 2 or 3 circuits contained within the same cable with conductors of electric light, power, or Class 1 circuits.

 

[tom baker]

For whatever type of wiring method you want to use (UF, TC) look in the NEC chapter for it, under uses allowed and not allowed. NMB is not allowed in a wet location , like inside a raceway. I would suggest LTFNMC, with UF or TC.

 

[Dennis Alwon]

For whatever type of wiring method you want to use (UF, TC) look in the NEC chapter for it, under uses allowed and not allowed. NMB is not allowed in a wet location , like inside a raceway. I would suggest LTFNMC, with UF or TC.

You can use nm thru the building and exit into a jb and use carflex from there.

 

[augie47]

Locally I see TC-ER-JP ('17 Code change), UF or a jacketed MC (connectors are costly).
Seldom see NM becuase of the "wet location" problem.

 

[shortcircuit2]

TC-ER-JP in residential only (or it must be in a tray or raceway)

Local supply houses carry this now...

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[LarryFine]

If I wired many split units, I would opt for single conductors in a flexible raceway, and not use a cable at all.

 

[Dennis Alwon]

If I wired many split units, I would opt for single conductors in a flexible raceway, and not use a cable at all.

We did more than one where the wire was 50-75' away with lots of twists and turns. You would not be able to do that.

Back then TC cable could not be used in a residence and the hvac guys would run that wire only to find out it would not fly.