Mini Split over Current Protection

[hbiss]

Wait, what?

A 40A breaker supplying two 40A 120V loads? e.g. 40A L1-N for the outside unit and 40A L2-N for the inside unit?

Ahh, no. A 2 pole 40A breaker supplying the condenser that's supposed to have a max breaker of 20A and the indoor unit that's only supposed to be supplied with a max breaker of 15A.

What's wrong with this picture?

-Hal

 

[jaggedben]

Ahh, no. A 2 pole 40A breaker supplying the condenser that's supposed to have a max breaker of 20A and the indoor unit that's only supposed to be supplied with a max breaker of 15A.

What's wrong with this picture?

-Hal

Everything is wrong with that picture.
I was trying to confirm he actually meant it was installed that way because I'm finding it hard to believe.

 

[LarryFine]

Ahh, no. A 2 pole 40A breaker supplying the condenser that's supposed to have a max breaker of 20A and the indoor unit that's only supposed to be supplied with a max breaker of 15A.

What's wrong with this picture?

The sub-panel is missing.

 

[mtnelect]

Are you sure about that?
I just looked at at spec. sheet for a random Daikin mini split unit and it shows the indoor unit to operate at line voltage. I have never seen a Daikin unit in person but all the Mitsubishi and Fujitsu units I have seen are line voltage between the outdoor unit and indoor unit.

The Daikin outside unit is powered by a dedicated AC circuit from the main panel. Then the outside unit powers itself through a power-controlled DC inverter, and microprocessor board. Then the inside unit(s) are controlled from the outside unit through high frequency AC voltages and pulses, through a 4/14 cable. This cable must be routed away from other cables to prevent interference.

 

[curt swartz]

The Daikin outside unit is powered by a dedicated AC circuit from the main panel. Then the outside unit powers itself through a power-controlled DC inverter, and microprocessor board. Then the inside unit(s) are controlled from the outside unit through high frequency AC voltages and pulses, through a 4/14 cable. This cable must be routed away from other cables to prevent interference.

Where does it say the wiring between the units is low voltage? If you look at a spec sheet of the equipment it will show otherwise.

 

[mtnelect]

Where does it say the wiring between the units is low voltage? If you look at a spec sheet of the equipment it will show otherwise.

You are correct ... that was my mistake.

 

[shieldcracker]

The OP is about a 1:1 mini-split system which means 1 outdoor unit serving 1 indoor unit. Depending on the Brand and the technology used, power can be delivered to the outdoor unit and then feed forward to the indoor unit (common); or power can be delivered separately to the outdoor and indoor unit (uncommon) or power can be delivered to the indoor unit and then fed forward to the outdoor unit (this case rare). Always check the IOMs.