Tap Load Calcs?

[BenjiF23]

I am overthinking this so looking for extra input to help end my brain fart:

Looking to tap off of existing 1200A rated feeders (120/208V) to a new 800A distribution panel (600A connected load).

That said, is there a way to calculate if this would disrupt the existing 1200A feeders or equipment?

Or since we are tapping the existing feeders, the existing 1200A feeders will only see the existing building load and the new tap feeders would only see the new 800A distribution panel load?

I have all conductor tap rules taken into consideration, but I don't see anywhere in the code that limits you on additional load added via taps, only requirements on feeder sizing and OCPD.

 

[jaggedben]

You will need to do a load calculation per article 220 to ensure that the 1200A feeder can supply the existing load plus your new load.

Unless some large amount of load was removed from the existing 1200A feeder at some point, what you're doing doesn't sound all that prudent.

 

[don_resqcapt19]

Tap conductors are a special case of feeder conductors. The feeder rules apply along with the special overcurrent protection rules in 240.21(B).