Ductless mini-splits circuit connection - Voltage Drop

[Cartoon1]

Hi All,

I have a ductless mini-split type A/C unit. This unit condenser circuit feeds the indoor unit (1 circuit) per manufacturer. My question is how do you typically calculate the voltage drop for something like this and how are they typically connected? For example: The condenser on the roof (above 3rd floor) and indoor unit is in the (1st floor hallway).

Distance: (Panel to condensor 50feet) ----- (condensor to indoor unit 50feet) ---- (Panel to indoor 10feet)

Assume the panel that is feeding the condenser is also on the first floor. Is the circuit going from the panel location to roof condenser to indoor unit?
Or is the circuit in the first floor being split on 1st floor where one is going to condenser (roof) and one is going to indoor unit 1st floor?

The voltage drop will be much higher if it is a full loop.

Thank you,

 

[Knightryder12]

I have never done a full loop distance on a circuit. In fact I have never heard that you have to do it that way. Also, typically, the AH (indoor) is fed from the CU (outdoor) by a specific cable provided by the manufacturer. I would not worry about voltage drop on that section at all since its typically DC.

 

[winnie]

Most times the indoor unit just has blower(s) and maybe a condensate pump. Very low current consumption.

The cable used to supply the indoor unit will likely be 14 ga for _mechanical_ reasons. The indoor unit cable pretty much follows the refrigeration lineset, and so has limited length. Voltage drop is almost certainly not an issue on the cable to the indoor unit.

On the Fujitsu units, the supply to the indoor unit is AC at the mains supply voltage. But that gets rectified to DC to run the electronically commutated blower motors, so any voltage variation will be controlled for.