Can the panel handle more HVAC units

[Willis1]

Have an existing 480Y/277V 3phase 400 amp panel backed up by a 600kw generator that has (2) 400amp output breakers. Panel currently has a couple 10 ton split systems installed. How do I find out if I can add more? I have all the cut sheets of the existing units and the new units they want to add. Not sure how to do the calculations to determine current load. The units only come on when ATS switches to gen power.

 

[kwired]

Have an existing 480Y/277V 3phase 400 amp panel backed up by a 600kw generator that has (2) 400amp output breakers. Panel currently has a couple 10 ton split systems installed. How do I find out if I can add more? I have all the cut sheets of the existing units and the new units they want to add. Not sure how to do the calculations to determine current load. The units only come on when ATS switches to gen power.

For a rather quick calculation 1 ton of refrigeration should be about 3.5 kW from an online conversion tool I used. That means your existing 20 tons is about 70kW. - about 84 amps before factoring in power factor and efficiency, and probably blower motors. Still guessing you can nearly triple your load before you are pushing a 400 amp circuit too far. Seems your generator is large enough to handle about anything you would put on a single 400 amp circuit but probably can't fully load both 400 amp breakers at same time.