Existing 600 amp/3 phase/120-208/ 4 wire/ Y service panel board contains an existing 3 pole 400 amp fused switch.
Phase A & Phase B of this 3 Phase, 3 pole 400 amp fused switch have been "double-lugged" to feed... (2) seperate 200 Amp/120-208 single phase main breaker feeder panels. (The double lugs on this 400 amp fused switch have been approved for the conductors.)
Both SETS of Feeder conductors from 400 amp fused switch (which does have 400 Amp rated fuses) to EACH 200 amp feeder panel are 3/0 THHN copper.
Question #1) Is this setup a NEC violation?
Question #2) Would having Phase A & B feeding one feeder panel AND Phase A & C (out of this 3 pole 400 amp fused switch) feeding second feeder panel make any difference, as far as NEC is concerned??
Confused because in the past, previous AHJ would allow on RESIDENTIAL... a 400 amp meter base only (no outdoor service disconnect)... to be double-lugged on load side of meter base, with 3/0 copper, to (2) separate 200 amp service panels, as long as outdoor disconnects were not required, due to distance, etc.
If the panelboard is marked 120/208 and it is connected to 120/240, will you write that up as a violation? I've had to do so a couple of times when electricians have used "loadcenter" grade panels. At least one manufacturer (Cutler Hammer) has 3 phase panels with plug on breakers listed for 120/208 only, if you want a 120/240 3 phase, you have to step up to a bolt on breaker.
Few things are harder to put up with than the annoyance of a good example.