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Old 04-18-2019, 04:51 PM   #1
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Default Mini-split inside unit Disconnect

Inspector is telling me that I need to install a disconnect for the inside head of a mini-split. Keep in mind that the outdoor heat pump has the lockable disconnect already in place. I'm I wrong about not being necessary? He didn't reference and article number either making it even harder to believe he is correct.
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Old 04-18-2019, 04:57 PM   #2
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Originally Posted by nherndon View Post
Inspector is telling me that I need to install a disconnect for the inside head of a mini-split. Keep in mind that the outdoor heat pump has the lockable disconnect already in place. I'm I wrong about not being necessary? He didn't reference and article number either making it even harder to believe he is correct.
Yes, it's required, just like a typical split AC air handler. A toggle switch will do.
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Old 04-18-2019, 05:14 PM   #3
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We have not been called on no inside disconnect yet. I would agree that it is necessary.
430.102(B)/(1) and (2). If your powers of persuasion of really high you might be able to win with exc (a) about it not being practicable. (As in the homeowner will not let me put anything else on the wall and when was the last time you tried to run a wire out of the inside unit terminal box. Good luck.
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Old 04-18-2019, 05:23 PM   #4
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Doesn't article 440.8 identify the two as a single machine? If not that then in 440.12 B to paraphrase says when two or more loads may be simultaneous on a single disconnecting means?
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Old 04-18-2019, 05:25 PM   #5
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We have not been called on no inside disconnect yet. I would agree that it is necessary.
430.102(B)/(1) and (2). If your powers of persuasion of really high you might be able to win with exc (a) about it not being practicable. (As in the homeowner will not let me put anything else on the wall and when was the last time you tried to run a wire out of the inside unit terminal box. Good luck.
Are you saying to run the power to the unit, then run a switch leg down to a switch to serve as a disconnect?

If so, I was thinking about that right after making my post, but I wonder if that's allowed? Reason being, there would still be power going to the unit. It won't run, but a service person could still get shocked while working on it.

The way I have done it is to just run the cable from the outside unit into a switchbox with a 2-pole switch, then run another leg up to the inside unit.
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Old 04-18-2019, 06:07 PM   #6
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Doesn't article 440.8 identify the two as a single machine? If not that then in 440.12 B to paraphrase says when two or more loads may be simultaneous on a single disconnecting means?
I think that is referring to ratings of controllers, not the location of disconnects. You need to install a disconnect at the fans in a walk in freezer or cooler even if there is a disconnect outside at the compressor.
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Old 04-18-2019, 06:31 PM   #7
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There is no requirement for a disconnect for the inside unit. The mini split is considered a single system and as such the disconnect at the outdoor unit is sufficient.


This question has come up many time over the years and cmp members have answered it saying what I stated above.
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Old 04-18-2019, 10:57 PM   #8
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422.3 clearly defines the inside unit as an appliance, not an air conditioner. The inside unit contains no compressor.
422.31 (a) says if your motor is not over 1/8hp (most ductless units are way under this) the breaker if within sight or a lockable disco not within sight is permitted to be used as your disconnecting means. Even the cheap home creepo pull out discos are lockable. When you disconnect the outdoor unit, the indoor unit is usually powered from the same source through the same outside disco.
I just did 7 of these units a few weeks ago. The wall units they used were .057 hp for the 2 ton units and smaller motors in the smaller heads. The ceiling cassette units were even better. The 4 ton units were under 1/8th.
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Old 04-19-2019, 07:05 AM   #9
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422.3 clearly defines the inside unit as an appliance, not an air conditioner. The inside unit contains no compressor.
422.31 (a) says if your motor is not over 1/8hp (most ductless units are way under this) the breaker if within sight or a lockable disco not within sight is permitted to be used as your disconnecting means. Even the cheap home creepo pull out discos are lockable. When you disconnect the outdoor unit, the indoor unit is usually powered from the same source through the same outside disco.
I just did 7 of these units a few weeks ago. The wall units they used were .057 hp for the 2 ton units and smaller motors in the smaller heads. The ceiling cassette units were even better. The 4 ton units were under 1/8th.
Joe, I get what you are saying but I don't believe that is correct-- the part about not being an a/c unit.

The minisplit is sold as a unit and in that sense it is considered part of the a/c unit. Since it is considered a single unit then only one disconnect is required. At least that is how NC and many other areas are looking at it.

For NC electricians here is the formal interpretation from the state.

Quote:
This document designates the term “mini split system” as specifically referring to a ductless heating, ventilation, and air-conditioning (HVAC) system that consists of both an exterior condenser unit and an interior blower unit; and is a complete listed and labeled engineered design manufactured so that the entire system receives its power supply at only one place from a
structure’s electrical system; and where control wiring, that is part of the same design, supplies power for all equipment within the system.

Question:
Does a mini split system require disconnects at both the exterior condenser unit and the interior blower unit?

Answer:
No, unless required by the manufacturer or listing instructions.
Mini splits systems as defined above are connected to the structure’s electrical system by one individual branch circuit. Because a mini split system is supplied with electrical power at only one point from the structure’s electrical system, the mini split system is one single machine as
defined by section 440.8 of the State Electrical Code. A single machine defined by section 440.8 shall be permitted to have a single disconnecting means to serve all the motors of a mini split
system as provided in section 430.122 Exception (a).

Section 440.14 requires a disconnecting means to be located within sight and readily accessible from the air-conditioning or refrigeration equipment. Therefore, the single disconnecting means shall disconnect the structure’s electrical system from the mini split system at only one point and
shall be located within sight and readily accessible from that point of connection.

For clarity, section 440.8 does not apply to a typical HVAC split system with air ducts because the air-handler and heat pump are separate pieces of equipment that are supplied by a minimum of two branch circuits from the structure’s electrical system.
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Old 04-19-2019, 07:19 AM   #10
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Dennis, what happens when someone needs to work on the interior unit, which is in a back office of a hospital behind multiple locked doors, and the outside unit is located on a roof somewhere behind a different handful of locked doors?

Hell, which one of the 6 units on the roof is the one powering the interior unit that needs to be worked on?

It just seems odd.
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Old 04-19-2019, 07:48 AM   #11
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NC thinks it isn't required.


CT does.


Quote:
2018 CT State Building Code

(Amd) 440.14 Location

(Add) Exception No. 3: Where the interior section of a factory packaged split system is fed solely from the exterior section of the system and the disconnecting means for the exterior section is capable of being locked in the open position, a separate disconnecting means for the interior section shall not be required within sight from that section. The provisions for locking or adding a lock to the disconnecting means shall remain in place with or without the lock installed.
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Old 04-19-2019, 08:01 AM   #12
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Dennis, what happens when someone needs to work on the interior unit, which is in a back office of a hospital behind multiple locked doors, and the outside unit is located on a roof somewhere behind a different handful of locked doors?

Hell, which one of the 6 units on the roof is the one powering the interior unit that needs to be worked on?

It just seems odd.
I am just stating what the interpretation is by the code panel members and the state of NC .

I have never seen mini-splits used in a hospital but I believe the idea is to hit the disconnect- which should be marked if there are more than one and that would kill power to the indoor unit
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Old 04-19-2019, 08:03 AM   #13
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I have never seen mini-splits used in a hospital but I believe the idea is to hit the disconnect- which should be marked if there are more than one and that would kill power to the indoor unit
I brought that up because I have installed quite a few in hospitals and remember how far it was between the units and how much of a pain it was to get security to give us access.
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Old 04-19-2019, 11:53 AM   #14
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I side with Dennis on this one. 440.8,it is a single machine. 440.3 B specifically excludes split systems from any 430 requirements. This concludes today's broadcast , we will resume programming at 6:00 AM tomorrow.
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Old 04-19-2019, 12:01 PM   #15
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I can't edit my above posts so hopefully people reading this thread will scroll down to see that I was incorrect.

I was so sure about this, I specifically remember Badger saying how it was required and how he used a toggle switch just like I did. Someone go to Holt's and yell at him for me please.
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Old 04-19-2019, 01:18 PM   #16
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We have been required by the local AHJ for years to install disconnects on the interior portion of small splits, even though there is indeed a lockable exterior disco feed. Argue it. Overruled. AHJ makes the final call. Pick your battles. Save it for the big ones. We just install a 3-pole toggle in a IR cover (yes I know 1 cond is just a signal, but that’s what makes them happy), and add the lab/mat to the proposal. We know it’s coming so we just do it. BTW, don’t forget your GFCI within 25’ of the exterior unit.
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Old 04-19-2019, 01:25 PM   #17
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The disconnect has to be with in sight.

Been using a two pole switch for a disconnect since I first installed them.
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Old 04-19-2019, 01:34 PM   #18
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Originally Posted by nherndon View Post
Doesn't article 440.8 identify the two as a single machine? If not that then in 440.12 B to paraphrase says when two or more loads may be simultaneous on a single disconnecting means?
The indoor unit is an air handler and needs a service disconnect in sight to work on the fan and or integral condensate pump.
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Old 04-19-2019, 01:41 PM   #19
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I don’t disagree. Makes sense to have one there regardless of what the code says. That’s why we don’t argue it.
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Old 04-19-2019, 01:59 PM   #20
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Technically you can size the circuit breaker to the exact size and install a lockout in the panel itself. Then you would not need a serviceable disconnect at the outdoor unit either. So to me it does not make sense to have a disconnect at the indoor unit of the system. Why is it more important to make it convenient for someone that might be servicing the equipment in the future, than it is to make it convenient to the installer? Furthermore if you are servicing the indoor unit why would you not also be servicing the outdoor unit. I could argue the ladder or the two is more important, but I'm not and HVAC guru.
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