Daikin Mini-Split

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crispysonofa

Senior Member
Location
New England
Occupation
Electrical and Security Contractor
I just wired up a Daikin mini-split that had two heads. When I usually install these I do not use a GFI breaker but the plumber insisted so I ordered an expensive GFI 240V breaker. The Daikin Condenser/heatpump outdoors does not have a connection for a neutral wire. I hooked up the GFI breaker, connecting factory installed neutral pigtail to the neutral bar in the panel. I left the space for the load neutral empty on the breaker since their isnt one for the unit. Before turning the disconnect on I verified 240V at the line side of disconnect, I verified 240V at the unit terminals. The unit will come on for about 3 minutes and then when the fan goes to kick on the GFI breaker trips. I am getting some mixed things about using GFI breakers with these units and am also questioning my breaker. Does anyone have any input? Maybe I should just install a standard breaker and be done with it?
 

GoldDigger

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Location
Placerville, CA, USA
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Retired PV System Designer
Chances are that the fan simply has too much unbalanced leakage to ground and is properly tripping the GFI when it turns on.
The alternative is that the GFCI breaker is false tripping.
I would carefully open the EGC connection to the unit, insert a milliammeter and measure the ground current while feeding the unit from a non-GFCI breaker. But that would not necessarily deliver a solution, just define the problem better. :)
What happens if you connect only one head unit?
 

crispysonofa

Senior Member
Location
New England
Occupation
Electrical and Security Contractor
Thank you for the reply. I was thinking this might be the case as well. I was doing a little weekend catch up, that's what I get for working on Sunday. My plan was to test the breaker, I have a QO panel at the shop I was going to put a load on it and see how it did. The other thing that makes me worry is that the plumber decided to wire the heads and when I got inside the outdoor unit I noticed that he did not strip the wires properly giving every conductor a haircut. I remade all the outdoor connections properly and am now thinking I might have to check the interior as well. I will know if the breaker is good. If I do not land the neutral pigtail from the breaker will it function as a normal breaker? Would it trip when I press the test button?
 
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manic67

Member
Location
Knoxville,TN
My first though is: why listen to a plumber about electrical work.
I've had a similar problem with variable speed pumps. The two pole gfi doesn't like unbalanced loads(especially GE). If the fan is being run off one leg, it will trip. If anything is being run of one leg, it will trip.
But why would you want to run an a/c unit off a gfic?
 

crispysonofa

Senior Member
Location
New England
Occupation
Electrical and Security Contractor
He told me that the warranty on the product would not be valid if the GFI was not installed. I wasn't going to argue about it. I may try to contact the manufacturer about it and see what they have to say.
 

sparky1118

Senior Member
Location
Massachusetts
Occupation
Master Electrician
Why did he want it GFCI protected? I install Panasonic mini split units and I've wired Daikin as well. I've never installed GFCI protection. I'm curious why he wants it?

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GoldDigger

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Location
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Retired PV System Designer
My first though is: why listen to a plumber about electrical work.
I've had a similar problem with variable speed pumps. The two pole gfi doesn't like unbalanced loads(especially GE). If the fan is being run off one leg, it will trip. If anything is being run of one leg, it will trip.
But why would you want to run an a/c unit off a gfic?
I doubt that the fan is being run off one leg if no neutral has been run to it. :)
The mini-split diagrams I have seen show only the two hot wires and a signalling wire are run to the inside units.
I suppose that there could be unbalanced leakage associated with the signalling wire which is close in potential to only one of the hot wires.

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ceb58

Senior Member
Location
Raeford, NC
My first though is: why listen to a plumber about electrical work.
I've had a similar problem with variable speed pumps. The two pole gfi doesn't like unbalanced loads(especially GE). If the fan is being run off one leg, it will trip. If anything is being run of one leg, it will trip.
But why would you want to run an a/c unit off a gfic?

I agree, what code section is the plumber sighting in the NEC?

The other thing that makes me worry is that the plumber decided to wire the heads

Why is the plumber doing any wiring?
 

MAC702

Senior Member
Location
Clark County, NV
My first though is: why listen to a plumber about electrical work...

That was mine, too.

FWIW, my two primary trades are electrical and HVAC. I've installed more mini split systems than I can remember. I've never put one on a GFCI breaker.

Here are the installation manuals: http://www.daikinac.com/content/resources/manuals/installation-manuals/multi-zone-ductless-systems/

I'm going to take a gander through one. I've never done a Daikin.

And there is it on page 12 of the outdoor unit instructions:
• Be sure to install a ground fault circuit interrupter. (One that can handle higher harmonics.)
(This unit uses an inverter. Therefore, a ground fault circuit interrupter capable of handling higher harmonics must be used in
order to prevent the ground fault circuit interrupter malfunctioning.)

Well, I'll be danged. The vast majority of the systems I've installed use an inverter.

So, does the one you installed "handle higher harmonics?" :ashamed: I've never looked for that before.

EDIT: So I just went through the big installation manual for a current LG multi-zone inverter unit. Lots of warnings about grounding it and using the proper size circuit breaker. Nothing about GFCI protection.
 
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MAC702

Senior Member
Location
Clark County, NV
...If I do not land the neutral pigtail from the breaker will it function as a normal breaker? Would it trip when I press the test button?

Does the breaker use its line-side neutral to power itself? Regardless, I don't think your problem is there.

Back to the "handle higher harmonics" issue, take this for what its worth. I know very little about Reddit, other than I've heard of it. Someone who claims to know what they are talking about says this: "the GFCI breaker IS NOT required and a letter confirming this can be obtained from the manufacturer of the minisplit (in this case Daikin). The breaker will absolutely trip upon startup. It isn't due to current draw but how the inverters work. A GFCI breaker rated for high harmonics (super-expensive) could be used. The reason it still exists in manuals is leftover from overseas manuals as they use different electrical system setups."

Found here: https://www.reddit.com/r/HVAC/comments/2xd5jg/do_you_specify_a_gfci_to_be_installed_with_a/

Makes me wonder how many of these the plumber has done. Bill him for that breaker.
 
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crispysonofa

Senior Member
Location
New England
Occupation
Electrical and Security Contractor
Ok, I think it will be worth my time to contact Daikin and put this to bed regarding GFI's. I only installed one because the plumber said it would void his warranty. I am interested to see what they have to say. I appreciate your insight thanks very much!
 

Little Bill

Moderator
Staff member
Location
Tennessee NEC:2017
Occupation
Semi-Retired Electrician
It was asked why the plumber was doing any of the wiring. I have another question....

Why is a plumber installing HVAC equipment?
 

hbiss

EC, Westchester, New York NEC: 2014
Location
Hawthorne, New York NEC: 2014
Occupation
EC
And there is it on page 12 of the outdoor unit instructions:
• Be sure to install a ground fault circuit interrupter. (One that can handle higher harmonics.)
(This unit uses an inverter. Therefore, a ground fault circuit interrupter capable of handling higher harmonics must be used in
order to prevent the ground fault circuit interrupter malfunctioning.)

"Be sure to install a ground fault circuit interrupter" doesn't sound like "this unit requires a ground fault interrupter" nor is there anything like not using one voids the warranty.

It just sounds like some friendly advice that a GFI would be a good idea and if you do use one be sure it's capable of handling higher harmonics or it will false trip.

Stupid plumber.

-Hal
 

MAC702

Senior Member
Location
Clark County, NV
"Be sure to install a ground fault circuit interrupter" doesn't sound like "this unit requires a ground fault interrupter" nor is there anything like not using one voids the warranty.

It just sounds like some friendly advice that a GFI would be a good idea and if you do use one be sure it's capable of handling higher harmonics or it will false trip.

Stupid plumber.

I give kudos to the plumber for reading the installation manual.

I do think the manual seems to say it's required.

I do think the plumber exaggerated it beyond that, and will probably be glad to learn that it may be a misleading requirement given the "harmonics" requirement which I don't think is something we have commonly available.
 

kwired

Electron manager
Location
NE Nebraska
Does anyone know of a QO GFCI 2 pole breaker that is designed for such higher harmonics?

I think this very well may be what is going on here:

The reason it still exists in manuals is leftover from overseas manuals as they use different electrical system setups."

If anything you maybe need EPD instead of GFCI - 4-6 mA leakage is possibly too low threshold and you need the 30-100 mA leakage threshold to ride through certain conditions while it is in use. You don't want to know how much a QO version costs compared to a GFCI.
 

Jraef

Moderator, OTD
Staff member
Location
San Francisco Bay Area, CA, USA
Occupation
Electrical Engineer
I agree, most likely a translation problem. Elsewhere in the world, "Ground Fault" protective devices are referred to as Residual Current Devices (RCDs). They can have much higher trip thresholds than we can for personnel protection, 30mA and higher; what we would call EQUIPMENT Ground Fault protection or now Class B and C GFP. But the term "GFCI" has a very SPECIFIC meaning here in North America, it means Class A Ground Fault Protection and cannot allow more than 6mA of ground current. That is often more than the common mode leakage current if anything inverter driven, hence the problems people have with inverter driven pool pumps and, apparently, mini-splits.

I think someone translating that manual from Japanese or Korean or Chinese or whatever just looked up the translation of "RCD" and found a reference to GFI then extended it to GFCI so they plugged that in, not knowing the difference. That happens a lot, especially with Asian mass marketers who don't really care much about the details in our marketplace. So if indeed someone has figured this out at the factory and will supply you with a letter stating that a GFCI is NOT required, then you will need to get that, because the NEC requires that all manufacturer instructions must be followed.
 

Jraef

Moderator, OTD
Staff member
Location
San Francisco Bay Area, CA, USA
Occupation
Electrical Engineer
Ok, I think it will be worth my time to contact Daikin and put this to bed regarding GFI's. I only installed one because the plumber said it would void his warranty. I am interested to see what they have to say. I appreciate your insight thanks very much!
When you contact then, understand that "GFCI" is different from "GFI" as well. GFCI is that narrowly SPECIFIC designation for a Class A GF protective device. GFI is a more generic term that could include the Class B and C devices that are NOT intended for personnel protection.
 
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