Busways

[Canton]

I have a couple of installations with meter stacks that have a 2000 and 1600 amp Main breaker, but than have feeder bussing with 1200 amp bussing/meter branches and 800 amp amp bussing/meter branches

Regardless of what the manufacturer says are permissible configurations, and these being feeder busing/busways with branch taps/OCPDS to go to apartments, how does the feeder busway ampacity comply with 368.17 when it has an OCPD larger (2000 or 1600 amp) than the busway ampacity 1200 amp/800 amp?

Even looking at TAP rules, it appears to be tapping a tap.

Any thoughts from the brain bank?
Thanks

 

[jim dungar]

Is the main breaker in the 'middle' of the metering bus bars? This way you have 2 taps from one device not a tap of a tap.

 

[Canton]

It is. But I have a 1600 amp Main with 1200 amp meter stacks (and 800 amp) on both sides with 125 amp TAPs/Branch breakers to the apartments.

1600 amp Main supplies 1200 amp meter stacks (and 800 amp) with 1200 amp bussing (and 800 amp) than has TAPs to 125 amp breakers

1600 amp Main ———-1200/800 amp feeder bussing———-125 amp internal TAPS/branch breakers

The 1200/800 amp feeder busways are not protected at their ampacity. How does this comply with 368.17?

 

[jim dungar]

If this is 'unitized metering equipment' its internal bussing taps are not subject to art 368.
Or is this a single main breaker that feeds separate busway runs that then feeds the meters?

 

[Canton]

I think I found my answer……take a look at 240.21(B)(1)(1)(b) exception for manufacturers equipment