(2) mini-splits, (1) breaker?

[Kline]

I am adding (2) mini-splits to my home, 240v, 15a max OCP per unit.

I have room for one DP breaker in my QO panel, I am not interested in adding a sub panel at this time.

I would like to run 10-2 UF, off one 30A DP GFCI(per Mitsubishi) breaker, this circuit would then hit (2) 30a, fusible A/C disconnects, each with 12A time-delay fuses installed.

While an unusual installation, does anyone see an issue with it?

The wire is protected by the breaker, the mini-splits are protected by the fuses.

Thanks for the feedback...

 

[kwired]

I am adding (2) mini-splits to my home, 240v, 15a max OCP per unit.

I have room for one DP breaker in my QO panel, I am not interested in adding a sub panel at this time.

I would like to run 10-2 UF, off one 30A DP GFCI(per Mitsubishi) breaker, this circuit would then hit (2) 30a, fusible A/C disconnects, each with 12A time-delay fuses installed.

While an unusual installation, does anyone see an issue with it?

The wire is protected by the breaker, the mini-splits are protected by the fuses.

Thanks for the feedback...

Not as unusual as you may think, the 30 amp portion of the circuit is called a feeder and each branch circuit starts at each fused disconnect.

 

[Little Bill]

Why are you using a GFCI breaker? Unless the mfg requires it, its not required.

 

[Kline]

Mitsubishi mentions putting GFI protection in locations that require it. I'm on the outside of the house...?

 

[Kline]

Mitsubishi requires it per instruction manual

 

[iwire]

Mitsubishi requires it per instruction manual

No only if code required and it is not.

 

[Kline]

No only if code required and it is not.

This is copied from the manual:










I'm interpreting that the "installation area" is the environment/location/etc the unit is located. Had they meant code or local jurisdiction, I think they'd have used that language? This is their installation spec's don't we have to follow them?

One could install the outside unit in a plant to feed a small office. In my mind that is an instance where one would not need the GFI, because the location is dry?

I'm just trying to do what's right. I don't mind installing the GFI if I have to, I'm just not convinced I don't have to.

 

[kwired]

This is copied from the manual: View attachment 14054










I'm interpreting that the "installation area" is the environment/location/etc the unit is located. Had they meant code or local jurisdiction, I think they'd have used that language? This is their installation spec's don't we have to follow them?

One could install the outside unit in a plant to feed a small office. In my mind that is an instance where one would not need the GFI, because the location is dry?

I'm just trying to do what's right. I don't mind installing the GFI if I have to, I'm just not convinced I don't have to.

That text from instructions is not very specific at all.

NEC does't automatically require GFCI protection just because you are outside or there is water in the vicinity. Most non cord and plug connected equipment is not required to have GFCI protection by the NEC, swimming pool areas one of the biggest exceptions to that as a general rule, there are a few other items, but nothing in there as relates to air conditioning or refrigeration equipment.

Most GFCI protection required by the general rules of 210.8 only applies to receptacle outlets that are 15 or 20 amp and 120 volts. Your mini-split likely does not have that for a supply and is not a situation covered by anything in 210.8.

 

[capybara]

two things to consider:
1. disconnect in sight of the condenser (outdoor part of the split unit) ?
2. 440.65 Leakage-Current Detector-Interrupter (LCDI)
and Arc-Fault Circuit Interrupter (AFCI). Single-phase
cord-and-plug-connected room air conditioners shall be
provided with factory-installed LCDI or AFCI protection.
The LCDI or AFCI protection shall be an integral part of
the attachment plug or be located in the power supply cord
within 300 mm (12 in.) of the attachment plug.

 

[iwire]

two things to consider:
1. disconnect in sight of the condenser (outdoor part of the split unit) ?
2. 440.65 Leakage-Current Detector-Interrupter (LCDI)
and Arc-Fault Circuit Interrupter (AFCI). Single-phase
cord-and-plug-connected room air conditioners shall be
provided with factory-installed LCDI or AFCI protection.
The LCDI or AFCI protection shall be an integral part of
the attachment plug or be located in the power supply cord
within 300 mm (12 in.) of the attachment plug.

I don't build them so I won't consider 440.65 even if this thread was about window units.

 

[kwired]

two things to consider:
1. disconnect in sight of the condenser (outdoor part of the split unit) ?
2. 440.65 Leakage-Current Detector-Interrupter (LCDI)
and Arc-Fault Circuit Interrupter (AFCI). Single-phase
cord-and-plug-connected room air conditioners shall be
provided with factory-installed LCDI or AFCI protection.
The LCDI or AFCI protection shall be an integral part of
the attachment plug or be located in the power supply cord
within 300 mm (12 in.) of the attachment plug.

The units in question here are not intended to be cord and plug connected, and should be a violation to connect them via cord and plug. With no cord and plug you eliminate the need for LCDI and as long as the unit is not 120 volts the need for AFCI as well.

 

[Dennis Alwon]

This is copied from the manual: View attachment 14054






I'm interpreting that the "installation area" is the environment/location/etc the unit is located. Had they meant code or local jurisdiction, I think they'd have used that language? This is their installation spec's don't we have to follow them?

One could install the outside unit in a plant to feed a small office. In my mind that is an instance where one would not need the GFI, because the location is dry?

I'm just trying to do what's right. I don't mind installing the GFI if I have to, I'm just not convinced I don't have to.

I think the area in question means in your area of the country where they may require gfci for some reason. I cannot imagine where they would require that but the NEC does not

 

[hbiss]

Why are you using UF? Will it be buried or exposed on the outside of the house at some point? Also I would probably use 15A fuses in the discos.

-Hal

 

[Mgarf33]

The gfci receptacle is to be located within 25' of the outdoor unit. Article 210.63 It is for corded use for a technician to perform servicing on the equipment, i.e. a vacuum cleaner, vacuum pump, etc..
This is not for connection of the equipment disconnect.
Not to mention, some gfci's have issues with some inverter type motors, as would be used in most mini split equipment.

Instead of using 2 separate disconnect boxes, why not use a double can breaker? This would eliminate a splice coupling.

 

[Mgarf33]

The gfci receptacle is to be located within 25' of the outdoor unit. Article 210.63 It is for corded use for a technician to perform servicing on the equipment, i.e. a vacuum cleaner, vacuum pump, etc..
This is not for connection of the equipment disconnect.
Not to mention, some gfci's have issues with some inverter type motors, as would be used in most mini split equipment.

Instead of using 2 separate disconnect boxes, why not use a double can breaker? This would eliminate a splice coupling.

Correction, I reviewed the manual and contacted Mitsubishi, as we routinely install their equipment.
This is a CYA warning from them. Speaking to the "tech rep", it's to be installed where either unit is installed near water. This would also include the indoor units, which are fed high voltage via class 1, listed 4- wire bundle by the outdoor units. I.e. an air handler installed in a bathing area or indoor pool area.

 

[kwired]

Correction, I reviewed the manual and contacted Mitsubishi, as we routinely install their equipment.
This is a CYA warning from them. Speaking to the "tech rep", it's to be installed where either unit is installed near water. This would also include the indoor units, which are fed high voltage via class 1, listed 4- wire bundle by the outdoor units. I.e. an air handler installed in a bathing area or indoor pool area.

For swimming pools NEC would already have restrictions on how close it can be to the pool, and possibly a zone that permits certain items if GFCI protected, but outside of that, GFCI protection goes back to the general rules of 210.8. Presence of water does not automatically mean GFCI protection is required by NEC.