Mr. Cool - Disconnect Toggle Switch

[Rock86]

Hey all, just helped a buddy of mine install a Mr.Cool ductless split system. I read previous threads, but i'm curious as to how often inspectors call out for disconnect switches at the wall mounted units? I discussed this with my mechanical guys and the other EE. We have never seen them with disconnects, but the manufacturer called for it. We debated in the office if NEC 422.31 would need to be met.
For those who know, the ductless splits come pre-wired and hosed, so someone would have to modify the manufactured wiring to install the disconnect switch.

 

[petersonra]

Is the disconnect between the inside and outside parts? Or is it to feed the whole thing?

 

[wwhitney]

We have never seen them with disconnects, but the manufacturer called for it. . . . the ductless splits come pre-wired and hosed, so someone would have to modify the manufactured wiring to install the disconnect switch.

I don't quite follow--the manufacturer calls for the installer to add a disconnect, but they make it hard to do?

If it's not required via 110.3(B), I have seen the argument that 430.112 Exception (a) permits the omission of a disconnect at the interior unit. Not sure if that applies.

Cheers, Wayne

 

[rc/retired]

I never required a disconnect for the head, (inside unit).
I don't have one on mine.

 

[electrofelon]

This is one of those hotly debated topics. One argument is that nothing in 440 applies because the interior unit does not have a hermetic compressor. Whether or not and what in 430 or 422 applies depends on whether it is considered an appliance, and the VA rating of the indoor unit.

 

[wwhitney]

the VA rating of the indoor unit.

Now that 422.31(A) and (B) are identical, are there other disconnect rules that depend on the VA?

Cheers, Wayne

 

[electrofelon]

Now that 422.31(A) and (B) are identical, are there other disconnect rules that depend on the VA?

Cheers, Wayne

the only thing I can think of off top of my head is that Article 424 has disconnecting means requirements that depend on horsepower rating.

 

[Rock86]

I don't quite follow--the manufacturer calls for the installer to add a disconnect, but they make it hard to do?

If it's not required via 110.3(B), I have seen the argument that 430.112 Exception (a) permits the omission of a disconnect at the interior unit. Not sure if that applies.

Cheers, Wayne

So the indoor unit has the refrigerant piping, and wiring (sjow cable) bundled together and installed on the unit. The manual tells you to install a disconnect at each indoor unit, but in order to it so that it complies with being in line of sight is to cut the cable.

I don't think 430.112 would apply... but

 

[Rock86]

Is the disconnect between the inside and outside parts? Or is it to feed the whole thing?

There is a disconnect for the outdoor heat pump. From that unit, a cable runs indoors to each indoor unit and the disconnect goes between the indoor and outdoor connection. This is to provide protection in the even someone needs to work on the indoor unit without shutting down the system.

 

[Rock86]

Now that 422.31(A) and (B) are identical, are there other disconnect rules that depend on the VA?

Cheers, Wayne

I've thought that as well.

 

[Rock86]

This is one of those hotly debated topics. One argument is that nothing in 440 applies because the interior unit does not have a hermetic compressor. Whether or not and what in 430 or 422 applies depends on whether it is considered an appliance, and the VA rating of the indoor unit.

Yeah, i saw that it was a hot topic in older threads. Name plate on the indoor unit claims a very minimal RLA... under 300 VA.

 

[Jraef]

If connecting power to fixed wiring, the following must be incorporated within it, in accordance with the wiring rules; an all-pole disconnection device...

I think you may have missed that opening part of the sentence. If it has a cord and plug on it, then it is NOT "fixed wiring",

 

[Rock86]

I think you may have missed that opening part of the sentence. If it has a cord and plug on it, then it is NOT "fixed wiring",

These are not cord and plug. just cord hahaha. But i'm not sure that you made the comment. I don't see where the comment came from, sorry.

 

[tom baker]

WA has exemption for the indoor unit in residential locations, meaning it’s required in any other occupancy. Art 430 requires a disconnect for motors.

 

[GoldDigger]

Common installation here is a snap switch (two circuit) mounted on the wall next to the (each) inside unit.
Third (control, but at L voltage) is problematic.
Two zone mini split is also quite comomon.

 

[Rock86]

Common installation here is a snap switch (two circuit) mounted on the wall next to the (each) inside unit.
Third (control, but at L voltage) is problematic.
Two zone mini split is also quite comomon.

That's what we did. The instructions call for an "Air-Break" Switch. My buddy looked that up before talking to me and he was freaking out a little hahaha. I set him straight though. All good now.

 

[Strathead]

Common installation here is a snap switch (two circuit) mounted on the wall next to the (each) inside unit.
Third (control, but at L voltage) is problematic.
Two zone mini split is also quite comomon.

Most that I have run in to require 3 poles. Two hots and the control (switch) leg. And this is a fixed appliance, so it would need a disconnect in my mind.

 

[Little Bill]

I see no need for an inside disconnect as power comes from the outside. There is a disconnect outside. I've never installed one inside.

 

[GoldDigger]

I see no need for an inside disconnect as power comes from the outside. There is a disconnect outside. I've never installed one inside.

But the outside disconnect is rarely within sight of the inside unit.

 

[Little Bill]

But the outside disconnect is rarely within sight of the inside unit.

A technician working on the unit would know to turn off the disconnect. At least he/she should or they have no business working on them. I never saw in the instructions, on the ones that I have installed, where there was any mention of an inside disconnect.