Non-coincidental loads 220.60

[spikebusters]

I have a house that we used the same branch circuit for the AHU/heater and the compressor load. We used the same size wire (#8 as per drawing) as called for on the drawings for the heater and the compressor load and installed a 2/30 amp breaker to reduce down (originally called for #10). We have done this many many times in the past. I have an engineer that insists he is not sure it is per code, yet he is asking us to install another 30 amp breaker at the AHU for the compressor. He asks us to show us which article allows for this. I know he is an idiot but I can't find anything to show him.

 

[Eddie702]

The equipment, both the condensing unit (compressor) and the air handler have to be wired in accordance with the equipment name plate.

If I understand what you are doing your taking a #8 feeder with probably a 40 or 50 amp breaker and running that to the AHU with electric heat. Then your tapping off the #8s and going to a 30 amp two pole breaker with #8s on the line side of the 30 a breaker and #10s on the load side to feed the condenser. You have to follow the tap rules and have disconnects in the proper locations as I am sure you know

As long as the electric heat is not run with the condenser you are probably ok. If the condenser is a heat pump your not because the electric heat will run during defrost. I would say with straight AC and electric strip heaters (no heat pump) your ok