Mini split - securing mc interconnect to line set

[electrofelon]

Ductless mini split with 14-3 MC used for the interconnect between outdoor and indoor unit. Assume there is a transition outside so MC is only in dry location. Can the MC be secured and supported by zip tying to the line set? I keep hearing inspectors citing "independent support". I assume they are referring to 300.11(B) and (C), but that only restricts fastening to electric stuff. I am not seeing anything in article 330 either. Opinions on this?

 

[Greentagger]

Would the last sentence of 330.30 help your case. Type MC cable fittings can be used as support?

 

[JGinIndy]

Above grid secured to line set. I would have to quote 300.11(B) and joking on my way out I would mention (D)

 

[electrofelon]

Above grid secured to line set. I would have to quote 300.11(B) and joking on my way out I would mention (D)

I am not securing the cable to any raceways. I don't see how that applies.

 

[JGinIndy]

300.11(B) yes Independent support is required. 300.11(D) that I mentioned was more in jest as in realistically the MC is not supporting “ Non Electrical Equipment “ Refrigerant Line Set. Also, I had a call just the other day about supporting TC-ER that Mitsubishi is requiring as transmission to indoor VRF units.

 

[kwired]

NEC for the most part doesn't address supporting wiring methods from other types of systems. It does pretty much prohibit supporting other systems from wiring methods though.

Common sense is to not do it - one exception possibly being where the two are associated with one another in some way.

control cables, interconnect, or even main power supply lines often have usually been permitted to be tied to refrigeration lines, gas pipes, etc. if both are associated with same equipement around here.

 

[electrofelon]

300.11(B) yes Independent support is required.

Please re read that code section. I believe this is a case of "Charlie's rule", the code doesn't way what you think it says. The word "independent" does not even appear in that section

 

[JGinIndy]

Please re read that code section. I believe this is a case of "Charlie's rule", the code doesn't way what you think it says. The word "independent" does not even appear in that section

I did I have, are you looking at 300.11(B)(2) which is the common above ACT install.

 

[electrofelon]

I did I have, are you looking at 300.11(B)(2) which is the common above ACT install.

I doesn't matter which sub number because (300.11)(B) does not apply at all:

300.11(B) Raceways Used as Means of Support. Raceways shall be used only as a means of support for other raceways, cables, or nonelectrical equipment under any of the following conditions:

There is no raceway being used as a means of support for my cable, so we don't even need to go to the conditions.

Is there some other section that applies?

 

[JGinIndy]

I doesn't matter which sub number because (300.11)(B) does not apply at all:



There is no raceway being used as a means of support for my cable, so we don't even need to go to the conditions.

Is there some other section that applies?

That’s (D) I thought we were talking about independent support methods for MC cable above grid? If so yes 300.11(B) applies. Maybe we should ask if the Mechanical Contractor has a concern if you attach to line set. The IMC is silent about securing to line set.

 

[wwhitney]

Electrofelon is looking at the 2014 code, JGinInday is looking at 2017 or 2020, the section lettering is different between the two.

Cheers, Wayne

 

[JGinIndy]

LOL yeah I thought something was off I just pulled out the 14 my mistake.

 

[electrofelon]

Electrofelon is looking at the 2014 code, JGinInday is looking at 2017 or 2020, the section lettering is different between the two.

Cheers, Wayne

Ah ok thanks. I am still not seeing (b) under 2017 code requiring independent support, seems to just give details if using wires as support.

 

[JGinIndy]

Pretty much the same just separated Cables and Raceways by adding subsection (D)

 

[JGinIndy]

It just boils down as I mentioned post #10 if Mechanical doesn’t mind if you use the line set. I always required the independent support especially when the distance from grid to deck is a ways up. If it’s just a couple of feet then just shot deck and tie wire it at deck. With the split systems / VRF the line set was not in their options. And sorry about our Code cycle separation I should have mentioned.

 

[kwired]

It just boils down as I mentioned post #10 if Mechanical doesn’t mind if you use the line set. I always required the independent support especially when the distance from grid to deck is a ways up. If it’s just a couple of feet then just shot deck and tie wire it at deck. With the split systems / VRF the line set was not in their options. And sorry about our Code cycle separation I should have mentioned.

From a physics perspective, what difference does that make? You are hanging the same cable off the same line set either way.

 

[gadfly56]

Ductless mini split with 14-3 MC used for the interconnect between outdoor and indoor unit. Assume there is a transition outside so MC is only in dry location. Can the MC be secured and supported by zip tying to the line set? I keep hearing inspectors citing "independent support". I assume they are referring to 300.11(B) and (C), but that only restricts fastening to electric stuff. I am not seeing anything in article 330 either. Opinions on this?

People are talking like you're running this 12' in the air in a plenum space or something. Is this just poke a hole through the wall for a couple of feet or what?

 

[JGinIndy]

People are talking like you're running this 12' in the air in a plenum space or something. Is this just poke a hole through the wall for a couple of feet or what?

That’s what I assumed when “independent support” was mentioned.

 

[JGinIndy]

From a physics perspective, what difference does that make? You are hanging the same cable off the same line set either way.

That was the point of the entire conversation. Can one “zip tie” mini split / VRF transmission cable to and along the line set? I assumed above grid and some inspectors allow it, some don’t, some mechanical contractors say no, some say yes. Where I worked in D.C. No. where I am now just north of Indy No.

 

[electrofelon]

People are talking like you're running this 12' in the air in a plenum space or something. Is this just poke a hole through the wall for a couple of feet or what?

This particular case it is the entire length of the line set, some runs may be around 60'. The line sets do not run through or in any plenums or fire rated assemblies.