I have an existing 40-amp subpanel: a 125-amp main-lug load center, wired to a 40-amp breaker in the main panel with 8-3 NM-B.
The subpanel has one existing load - a minisplit heat pump. I wish to add a Level 2 EV charger to it. I'm unclear as to what size charger is acceptable.
Here is the technical manual for the existing load (minisplit), mine being the largest '15' size: https://portal.fujitsugeneral.com/files/catalog/files/%28D&T%29%20ASUG09-15LZAS.pdf
Page 2 of the manual (page 6 of the pdf) shows the "maximum operating current" as 13.4 amps, and the "rated" current as 5.2 amps. On page 68 (page 72 of the pdf) the "minimum circuit ampacity" is specfied as 16.5 amps.
The two EVSE under consideration are rated at 16amps and 20amps, respectively (calling for a circuit 125% as large).
Clearly the 16-amp model, protected by a 20amp breaker in the subpanel, is acceptable. But what about the 20amp model ? There seem to be two issues.
I know a branch circuit supplying a continuous load must be rated at 125% of the load. But I don't believe that's the case with a panel, that the panel's rating must be 125% the sum of all the loads of all the branch circuits served by the panel. So I don't believe I'm restricted to 32 amps (80% of 40-amps).
I'm also unsure which figure to use for the minisplit: 5.2 amps, 13.4 amps, or 16.5 amps.
Will the 20-amp EVSE fail to be code-compliant, or is the only issue nuisance tripping, which seems unlikely given the typical operating currents of the minisplit ?