Feed Thru Lugs Question

[AZJeff2013]

I am designing a hotel and have a question concerning feed thru lugs / panels. I am bringing 400A to each guest floor and landing in a 400A M.L.O. panel (panel 'A'). Panel 'A' then feeds thru to Panel "B"which feeds thru to Panel 'C'.

Question 1 Are all 3 panels rated 400A or can Panels B and C be rated for the actual load they carry. In this case 200 and 100 amps respectively.

Question 2 When specifying the last panel in the chain (Panel C), does it need feed thru lugs or just normal lugs. Not sure since it is being 'fed thru' to from Panel 'B'

Thanks for any help on this matter.....

 

[John120/240]

All three panels are fed by your 400 A breaker. If you had a 200 A breaker between panel A & B, a 100 A breaker between panel B & C this might fly. But that set up negates your use of feed thru lugs. I've been wrong before, Others will chime in.

Panel C only needs lugs on one end.

PS Have you ever worked at your prison in Marion ?

 

[kwired]

Each panel needs to be protected at or below its rating.

Conductors supplying each panel need to be protected at or below their rating (with exception of the next standard size rule)

To be able to use smaller conductors you could use feeder tap rules if distances between are short enough for a particular tap rule, but in general the feeder tap will need to end in an overcurrent device so that means a main is still needed either at one end or the other.

Depending on how loads end up distributed I may go with the 400 amp panel and subfeed to a second 400 amp panel then install a 100 amp feeder and 100 amp panel on the last one, or it may very well be less cost to install the first panel as 400 amps then run two separate 100 amp feeders to each of the other panels and of course use 100 amp panels.

BTW there is nothing prohibiting running the feeder for panel #3 through panel #2 other then to make sure you don't overfill wiring "gutters" of the panel, which is probably not that likely to happen .

 

[AZJeff2013]

All three panels are fed by your 400 A breaker. If you had a 200 A breaker between panel A & B, a 100 A breaker between panel B & C this might fly. But that set up negates your use of feed thru lugs. I've been wrong before, Others will chime in.

Panel C only needs lugs on one end.

PS Have you ever worked at your prison in Marion ?

NEVER HAVE WORKED THERE OR LIVED THERE