Originally Posted by
Jerome W. Young
The main has 2 300 amp fuses which is 600 amp total
Nope, that's 300 amps fore each leg, for 300 amps total.
The two adjacent downstream non service panels each have 200 amp breakers. I am alittle confused obviously.
I am also confused.
Those 200 amp breakers, are they the breakers that feed the downstream panels, or are they mains in those panels?
The main 300 amp fuses are not overfused for the 400 amp rating of the main, however (and this depends on how the lower rated downstream panels are protected) the downstream panels *may* be ... or ... *may not be* ... overfused at the main.
Look at it this way:
Start at the down stream end, what is the rating of those panels and the conductors feeding them, and is the rating of the overcurrent device protecting them the same as, or smaller than, those ratings.
Next, move upstream to the next panel and repeat the above.
Then move upstream to the main.
As long as the overcurrent protection is the same as or smaller than the rating of the equipment it is protecting, then 'that part' is okay.
Also remember that there are two hot phase legs with a single phase service, and that each phase leg must have *the same* size overcurrent protection, and that the total rating *is not the sum of* those two overcurrent protective device, but *is the same as* each identically protected phase leg. In this case, think of it not as '1 + 1 = 2', but as '1 in & 1 out = 1 total'.