Im trying to understand the concept of amperage ratings for panels, and sub panels, but I'm not sure I have it figured out, sorry for any novice terminology.
I'm in America. Grounds omitted for clarity. Thanks!
Let's say I have a 100amp main service panel (two hots at 120v each and a neutral coming into it).
I install a 60amp double-pole breaker in my main. (Lets say for ease of example that this is the only breaker in the main panel, aka nothing else is using electricity in the main panel.)
I run 6 gauge feeder wires (two hots, one neutral) from this 60amp double-pole breaker to a smaller 60amp panel, a few feet away.
This sub-panel has a 60amp main breaker.
Now I install four 20amp single pole breakers, all in line, so two on each leg.
Now lets say I install four total 20amp single outlet receptacles, 1 outlet per circuit (using 12 gauge wire).
I have four theoretical high powered devices and i plug one into each outlet and turn it on. Each device continuously draws about 1,920 watts. So in total i am drawing about 7,680 watts (four x 1,920 watts).
The 60amp sub-panel can handle this because it is less than 14,400 watts (60amp x 240v). Is this the correct way to calculate this?
Now lets say i double up and install eight 20amp single pole breakers, and eight total 20amp single outlet receptacles, one on each circuit -- but now i also have eight total high-powered devices, and i plug one into each receptacles and turn them all on.
Each devices continuously draws about 1,920 watts. So in total i am drawing about 15,360 watts (eight x 1,920 watts).
This would trip the breaker in the sub panel, because it is over the 14,400 watts (60amp x 240v) it can handle, correct?
If this is all correct, then I am wondering this:
In the first example, I installed four 20amp single-pole breakers, two on each leg. But what if i install them all on one leg -- for instance, I leave a space between each breaker I install.
Now I run the same experiment -- one 20amp outlet on each circuit, four devices total, each plugged into one outlet. Each device draws 1,920 watts, for a total of 7,680 watts (four x 1,920 watts).
Would the 60amp breaker still be fine, or would it trip because all the circuits, and therefore devices, are on one leg?
Essentially I'm asking, would i still calculate the amount the breaker can handle by multiplying 60amp by 240v, or would i now have to multiply 60amp by 120v, which would only be 7,200 watts (less than the 7,680 watts my devices are drawing).
Thank you so much for your time!