Mini-Split Disconnect??

[jahilliard]

We installed a Mini-split system, or I should say the electrical for it. We have done the electrical in several different AHJ's for mini-splits and have never once been required to have an additional disconnect for the Air Handler inside the building...now we have a failure notice on an inspection requiring a disconnect at the Air Handler as well?? Curious what experience you all have had with this or why/why not a disconnect would/would not be required for the Air Handler??

 

[Ragin Cajun]

Sounds familiar.

As an engineer I often must design for the worst case of AHJ inspection.

I do call for a disconnect for the air handler. The only issue is often you have to disconnect three wires, even though it's only 120V. Depends on the unit. Look closely at the vendor wiring diagram. SOME AHJ's have allowed a plug, but check ahead of time.

RC

 

[GoldDigger]

:thumbsup:
Of the ungrounded wires, only one is nominally power but the control wire may be signalling by a low offset voltage from the hot wire in some cases.

Tapatalk!

 

[iwire]

Its a motor an insight disconnect is required.

Also I bet if you look at the instructions it shows one.

 

[iwire]

:thumbsup:
Of the ungrounded wires, only one is nominally power but the control wire may be signalling by a low offset voltage from the hot wire in some cases.

Tapatalk!

In my experience the indoor unit is 208 or 240 so a two pole disconnect switch is needed. Sometimes we use a 3 pole and break all three including the low volt signal wire.

 

[tom baker]

If you are in Washington we have an exemption for mini splits in dwelling units, no disconnect required.

 

[GoldDigger]

In my experience the indoor unit is 208 or 240 so a two pole disconnect switch is needed. Sometimes we use a 3 pole and break all three including the low volt signal wire.

This two or three pole disconnect could be just a snap switch, yes? Or is a visible break required?

 

[iwire]

This two or three pole disconnect could be just a snap switch, yes? Or is a visible break required?

Two pole right or wrong I have used a standard snap switch

Three pole we use 30 amp 3 pole manual motor starters. They fit in a standard box.

 

[jahilliard]

IMO the correct response would be NEC 110.3(b)...and the instructions show NO disconnect between the outside and inside unit. AND I have yet to see ANY mini-split anywhere to ever have a disconnect inside. It would look terrible having a disconnect mounted inside an office like that. We installed one in our offices and had it in inspected just yesterday and it passed final just like the tons of others. I have just never been asked to put a disconnect inside. So per 110.3(b) and the installation instructions provided I am disputing the "failure"..we'll see what happens.
BTW..this particular unit is a 3ph 208V Mitsubishi

 

[jahilliard]

Instructions

Instructions


Notice no disconnect between indoor and outdoor units

 

[iwire]

I can show you many instructions that show one.

But regardless the NEC requires one baring local amendments. Its a motor.

As far as looks not the NECs concern but we use a wall switch beside the unit in a color to match other devices

 

[augie47]

The other inspectors in this area and I required one based on 430.102(B).

(admitting that when HVAC folks from some other areas are informed of the requirement we are often faced with "Oh! You are one of those"
You many draw your own conclusions as to who "those" are .. I prefer to think they are referencing "those inspectors who follow the Code " )

 

[Wenty4]

mini-split disconnect

mini-split disconnect

you may want to check Article 440.14 which tells you that the disconnect for AC and refrigeration equipment shall be within sight of. There is no exception in your case to allow a lockable disconnect to be installed outside to disconnect both units. Having said that, I feel that with these systems being installed everywhere lately that a second disconnect inside is both redundant and ugly, but code compliant

 

[jahilliard]

I guess it's an interesting argument. The one we have in our office doesn't even have an access on the bottom or side for any way to tie any kind of conduit or cable etc. They are designed to install the factory provided cable along with the set line straight into the back from the exterior of the wall/building where the condenser is. And the fact is that we have installed A LOT of these all over SWFL and not one has a disconnect on the inside...I have never heard or have yet to see one like that installed by anyone. I would actually be curious to see a picture of that type of installation if one of you guys wouldn't mind posting one. Also, what about voiding any warranty for the equipment by cutting the cable provided as well as drilling a hole in the side of the interior unit?? I don't know man, seems just totally impractical, and according to 110.3(b) it SHALL be done the way I do it to be CODE compliant. :?

 

[augie47]

Curious, what kind of "cable" ?
I ask as we have had a ongoing battle involving inspectors, installers, UL and ETL.
Some of the units in this area had instructions that showed using SOOW cord, which we see as a violation of 400.8; others came supplied with TC, which we see as a violation in residential installs unless installed in a raceway (336.12).
I have a HUGE folder of correspondence from ETL, UL,. etc. discussing the UL standard used in the ETL listing and so forth.
Part of the problem is that a lot of the units were manufactured outside of the US and a lot of the instructions show methods acceptable by Canadian Code and not the NEC.
I has been a real headache for inspectors and contractors in this area.
In a number of the local installations the contractors use NM cable, routed thru a switch box with a DP switch. (The NM is transitioned to THWN on the outside).;

 

[mgookin]

When I saw the 208v 3p supply it made me wonder just how "mini" that split system is. I'd question it too. That's an air handler without a doubt. As far as I have ever known, a workmen's disconnect is required inside and outside for every split system. I've never known size of the system to dictate that requirement.

A UL Listing or listing to UL Standards (by other than UL) does not authorize a violation of the NEC.

I can appreciate the prediciament the OP is in. He has a manufacturer's installation sheet showing the installation without the disconnect and the NEC says to follow the manufacturer's installation instructions.

I'd contact the manuacturer and ask them to resolve it with the AHJ. Even though it was likely made overseas and sent over on a boat, they likely have local (north america) reps here. They will go to great effort to see that their product is allowed to be installed; without that they have no business.

 

[Bwas]

I have always required a disconnect switch adjacent to the indoor unit. I have never hear of or seen one installed without a switch and I can't imagine how any inspector could knowingly approve an installation without a switch. This would seem especially important in a residential installation where a homeowner might try to 'fix' a problem without understanding how the unit is wired.

 

[iwire]

I don't know man, seems just totally impractical, and according to 110.3(b) it SHALL be done the way I do it to be CODE compliant. :?

No, you must follow 110.3(B) and any other NEC requirements that go beyond it.

Also, what about voiding any warranty for the equipment by cutting the cable provided as well as drilling a hole in the side of the interior unit??

I have never used a cable provided by the maker to install a split system, that would be an NEC violation. The HVAC guys here know that so they do not buy it.

We use pipe and wire or MC / NM cable.

I would actually be curious to see a picture of that type of installation if one of you guys wouldn't mind posting one.

Sure, here is a pair I did last summer, one wall unit one ceiling mount.

 

[iwire]

When I saw the 208v 3p supply it made me wonder just how "mini" that split system is. I'd question it too. That's an air handler without a doubt.

We install some fairly small mini splits in data rooms loss prevention rooms, small labs etc. that are 3 phase.

The indoor fan is single phase, its only the compressor that is 3 phase.

 

[jahilliard]

I appreciate the pictures...again I have NEVER ever seen a disconnect on a mini-split on the indoor unit. The AC guys here, including the one I share a building with have never seen one either. The inspector for the unit at our office couldn't get access to the indoor unit because the door was locked at the time...but he told the AC guy it didn't require a disconnect so he didn't need to see it. Also, the "cable" is provided along with the units..it doesn't have to be ordered separately or anything...it's included as part of the equipment/materials provided from the manufacturer. I really don't have a problem doing it...I just can't stand doing something because "I said so" from an inspector, that doesn't fly with me and shouldn't with anyone else either. Again, I really do appreciate the pics, as I have yet to see one installed that way.
Just curious, are those units in the pics "back to back" or are the CU's outside somewhere else around the building??