Can I use a 220v 60 amp breaker and 4/3 line for a sub panely with 2 breakers 220 1 35 amp and 1 15 amp

Question

I have two old package heatpumps supplied by what looks like 4/3 lines each on its own breaker. 60 amp fuses. I am installing two split units the condenser requires 220 and 20 or 35 amp depending on if I run it in 2 ton or 3 ton mode. Plan is to start wit 2 ton mode. The air handler takes a 220v 15 amp fuse. So worst case I have 50 amps more likely 35 amps. I do not want to run to more lines to get 4 circuits at that location, likely $400 just for the wire. So I want to take each 60 amp 220v circuit run it to its own sub panel with two 220v circuits summing 50 amps or less. To stick with code I then need to have a disconnect on each circuit at the unit a few feet away. Any issues with this, I want to stay 100% safe. The old units are or WERE beasts, the new ones high efficient inverter technology with variable speeds with no hard starts so a lot easier on the entire circuits.

Looking for confirmation on my plan as safe and PROPER. Will verify the wires are 4/3, would it still work of they are 6/3. Plan to start tearing down and seeing what the wires actually are tomorrow. Thanks

Answer 1

As long as you have the clear space, go for it

You should have no problem installing a small NEMA 3R "spa box"-sized subpanel in place of the existing disconnect and running your flex whips directly from it. Just make sure that you have the NEC 110.26(A) required clear working area (30" wide, 36" deep) at the disconnect location before you start, as HVAC installers don't always remember that when fitting local disconnects. Also, you'll need to make sure the panel has a grounding bar fitted and remove the bonding screw from the neutral bar on the panel.