Running two mini-splits off the same breaker

[Mortimer452]

Getting ready to install a couple mini-splits in my workshop, both are 240V. One is a 4 ton, 42A max current, recommended breaker size 50A. Second is 1.5 ton, 16A max current, recommended breaker size 20A.

They're going to be located right next to each other outside. My question is, does each unit have to have its own breaker, or can I run both off a single 60A breaker with two appropriately sized fused disconnects (one 20A and one 50A). Trying to save the slots in my panel (and less wires to run).

 

[wyliesdiesels]

you essentially would be putting in a subpanel with that setup.

Dont forget the service outlet if you dont have one nearby

 

[Zeke]

The short answer is no if they are to be wired with 240v. I don't know of any 4-ton units that would run on 120v. If so, it would be debatable in my book.

Edit: OK so a sub panel would be ideal. I didn't think he asked that.

 

[Mortimer452]

you essentially would be putting in a subpanel with that setup.

Dont forget the service outlet if you dont have one nearby

Didn't think about a subpanel, but I suppose I could just put a small 2-slot 60A outdoor-rated subpanel, then feed two nonfused disconnects off that. Actually, in that case, I suppose I probably don't even need the disconnects, since having the breakers right there probably meets the disconnect requirement?

 

[wyliesdiesels]

Didn't think about a subpanel, but I suppose I could just put a small 2-slot 60A outdoor-rated subpanel, then feed two nonfused disconnects off that

If the nameplate on the compressors call for fuses then you would need to use fused disconnects.

Do you have an outlet near the compressors?

 

[Mortimer452]

If the nameplate on the compressors call for fuses then you would need to use fused disconnects.

Do you have an outlet near the compressors?

They do not call for a fused disconnect, they just list a "recommended fuse/breaker size of 50A" for the 4ton and 20A for the 1.5ton. I believe it's up to the installer whether the 50A protection occurs at the breaker or a fuse. My thought is, I can run both off a single 60A breaker, then used two fused disconnects (one 50A and one 20A) to meet that requirement.

Yes, I have a 20A regular GFCI outlet within a few feet of where the compressors will sit

 

[wyliesdiesels]

They do not call for a fused disconnect, they just list a "recommended fuse/breaker size of 50A" for the 4ton and 20A for the 1.5ton. I believe it's up to the installer whether the 50A protection occurs at the breaker or a fuse. My thought is, I can run both off a single 60A breaker, then used two fused disconnects (one 50A and one 20A) to meet that requirement.

Yes, I have a 20A regular GFCI outlet within a few feet of where the compressors will sit

what is the exact wording on the nameplate?

dO you have a pic?

 

[Bert_]

A 60A breaker feeding 2 fused disconnects is the same as using a 60A breaker to feed a sub panel. Each unit will still have individual overcurrent protection.

I agree with wanting pic's of nameplate. The currents you listed seem pretty high for the size of the unit. I'd be expecting more like ~10A for the 1.5 ton and mid 20's for the 4 ton.

 

[Mortimer452]

A 60A breaker feeding 2 fused disconnects is the same as using a 60A breaker to feed a sub panel. Each unit will still have individual overcurrent protection.

I agree with wanting pic's of nameplate. The currents you listed seem pretty high for the size of the unit. I'd be expecting more like ~10A for the 1.5 ton and mid 20's for the 4 ton.

They are Mitsubishi H2i Hyper-Heat mini-split heat pumps. Model MXZ-8C48NAHZ for the 4-ton and MUZ-FH18NA2 for the 1.5ton. I don't have the units on site yet, just trying to get the electrical part done for the HVAC installers in a few days. Those amperage ratings are stated in the installation manual.

 

[ant.foste]

A 60A breaker feeding 2 fused disconnects is the same as using a 60A breaker to feed a sub panel. Each unit will still have individual overcurrent protection.

I agree with wanting pic's of nameplate. The currents you listed seem pretty high for the size of the unit. I'd be expecting more like ~10A for the 1.5 ton and mid 20's for the 4 ton.

The Fujitsu 18,000 with two heads I installed in 2017 called for a 15 amps at 240vac. If I still owned that house I'd go outside to snap a picture.

 

[Milton Shaw]

4 ton rating is not a mini-split. It may look like a mini but that capacity is equivalent to a full size. Just doesn't have the duct work. Are you sure you would not be better off with duct work and more evenly split air flow for more room comfort.

 

[Mortimer452]

4 ton rating is not a mini-split. It may look like a mini but that capacity is equivalent to a full size. Just doesn't have the duct work. Are you sure you would not be better off with duct work and more evenly split air flow for more room comfort.

I'm pretty well settled on mini-splits for the shop, we have them in the house and absolutely love them. Cost-wise the difference is negligible, maybe even cheaper to go ductless, especially considering having to bring in propane lines or a second propane tank for the furnace (and the wildly fluctuating price of propane from year to year)

 

[theoldwizard1]

G... can I run both off a single 60A breaker with two appropriately sized fused disconnects (one 20A and one 50A). Trying to save the slots in my panel (and less wires to run).

The short answer is YES !

You need an 120V outlet within a specified distance of these units for service.

FYI - Large capacity mini-splits or ones that have multiple air handlers connected are less efficient.

 

[matt_i]

The short answer is YES !

You need an 120V outlet within a specified distance of these units for service.

FYI - Large capacity mini-splits or ones that have multiple air handlers connected are less efficient.

I disagree because this scenario requires landing 2 wires under the same pressure pad or pressure screw somewhere in the system. I regard this as poor wiring practice and should be avoided at all costs. Easiest solution is to put in a 240vac subpanel. Menards has a 4 slot (2 double poles) panel for under $25, which does not include the correct breakers.

 

[dcg9381]

The Fujitsu 18,000 with two heads I installed in 2017 called for a 15 amps at 240vac. If I still owned that house I'd go outside to snap a picture.

I have Daikin 24k units (2 ton). Their spec is 20A breaker.
I have them running (currently) on 15A breakers (as I originally had a different 24k unit picked out). They have not tripped the breakers - so I haven't gotten around to replacing them, but new breakers are sitting on the sub panel.

If you're asking if you can run a 50A spec and 20A spec Ductless ACs on a single 60A circuit, I'd say that the chance of that working just fine is very high..

I agree with the others - that for your install, I'd be looking at an exterior grade subpanel. The breaker protecting that subpanel can be 60A (assuming correct wiring) and the sum of the breakers inside 50 + 20 = 70A is fine.

I wasn't able to parse out if AC disconnects are still required in this case or not, it's not entirely clear to me. Non-fused disconnects *may* still be required - like I said, not clear... But AC disconnects can be had for like $20.


I wasn't aware of the requirement for a 120V service outlet (and I'm not compliant with this), so I looked it up:

"210.63 Heating, Air-Conditioning, and Refrigeration Equipment Outlet. A 125-volt, single phase, 15- or 20-ampere-rated receptacle outlet shall be installed at an accessible location for the servicing of heating, air-conditioning, and refrigeration equipment. The receptacle shall be located on the same level and within 7.5 m (25 ft) of the heating, air-conditioning, and refrigeration equipment. The receptacle outlet shall not be connected to the load side of the equipment disconnecting means."

Exclusion: (A receptacle outlet shall not be required at one and two-family dwellings for the service of evaporative coolers.)


One solution would be to use my favorite exterior rates sub-panel:
Siemens TL137US Talon
It's got 4 slots for the two breakers you need, includes a 20A GFCI "service outlet" on a separate circuit.. And has a 50A @ 240V / 30A @ 120V outlets - lots of options for running an RV, a welder, whatever..

 

[Norcal]

If a 60A feed was run either a loadcenter or fusible disconnects would have to be used to comply with data plate requirements. A 4 space NEMA type 3R panel would be ideal.

 

[rlitman]

Didn't think about a subpanel, but I suppose I could just put a small 2-slot 60A outdoor-rated subpanel, then feed two nonfused disconnects off that. Actually, in that case, I suppose I probably don't even need the disconnects, since having the breakers right there probably meets the disconnect requirement?

Exactly. My understanding is that breakers in a subpanel in sight of the equipment satisfy the disconnection means perfectly, and that also makes it very easy to add a third breaker for a 120V service outlet. I think this would be the easiest solution (though not necessarily the most cost effective).