Feeder calculation

[sparkync]

It's been some time since I've figured up a "feeder". I've just got a small building, around 12x20 (240 sq. ft.) that is being used as a "guest house" for the family's children (adults), when they come in from out of town. There are 8 general use outlets, including one outside outtlet, and 2 small circuits with 2 outlets each for counter outlets for "coffee pot", etc. (very small counter space), 1 garbage disposal outlet, and 1 very small undercounter refrigerator. There is (1) 15 amp 120 volt "mini split" heating/ac unit. If I figure it like a regular living space, and figure the "general use outlets" at 3 volt amp. per sq. ft. (720 watts), figure 2 appliance circuits at 1500 watt each (3000 watts), the garbage disposal at 600 watts (very small disposal), undercounter refrigerator (600 watts), the mini split system at (16 amps x 125% =20 amps (2400 watts)
I get 7320 watts. 1st 3000 at 100%, remainder (4320) at 35% = 1512 watts, for a total of 4512 watts/240 volts = 18.8 amps?? I must have done something wrong.
It's been around 35 years, give me a break
I figured if I pull a 60 amp service to it, that would be more than sufficient.

Thanks for any thoughts.

 

[suemarkp]

The HVAC goes in at 100%, it doesnt get the excess at 35% discount. For the mini split, just use its MCA value, as it already has the 125% factor in it.