Heat Pumps

[GThomas23]

If I have 3 outside heat pump that have 2) 16.5A and 1) 9A FLA Can I install a 100A 8 Circuit sub-panel to feed them? I would be pulling the feed from a 200A 42C ML panel. Can I run #2-3 RX (copper)?
GT

 

[Dennis Alwon]

Sure you can but #2 and 100 amp is way more than you need. Add the 3 compressors together and figure 125% of the largest. I believe you only need a 60 amp feeder-- #6 will do.

 

[Dennis Alwon]

When you say a 42 circuit panel I am thinking non residence. I am assuming that RX is okay to pull in this situation.

One other note is you don't have to pull a grounded conductor to the panel if you don't need one. I would advise to bring a neutral there so you can wire a receptacle to service the units.

 

[GThomas23]

Thanks, This is a single family home. 2-3 RX is 3 conductors and a ground. I did that so I could put a service outlet by the equipment.
GT

 

[infinity]

Sure you can but #2 and 100 amp is way more than you need. Add the 3 compressors together and figure 125% of the largest. I believe you only need a 60 amp feeder-- #6 will do.

Do these units have a nameplate Minimum Circuit Ampacity rating? If so I don't see a need to add 25% to the calculation if you're using the MCA since each units' MCA already contains the extra 25%. But I do agree with Dennis since the OP mentioned FLA not MCA.