Square D Panelboard Series Rating

[shrimp_sushi]

Hello,

I have a series rating question not specific to just Square D, but in my specific case, I'm looking at a Square D system.
In this branch, there is a main switchboard that's feeding a panelboard with a 200A JJ type breaker, rated for 65kAIC. The downstream panel is an NF panel with EDB breakers. These two types are series rated for 65kAIC according to Square D's latest series rating chart. However, the panelboard also has a main breaker that is a type JD, rated for 18kAIC, and this type is not listed as part of the series rated breakers. Basically looks something like this:

-MSB- ---------------------Panelboard--------------------
200A JJ --> 200A JD (Main breaker) --> EDB (Feeder breakers)

Will the series rating still be valid here, since the upstream type JJ feeder breaker is in series with this type JD main breaker? Or would it be a valid recommendation to remove the main breaker since it's redundant and also invalidates the series rating?

 

[jim dungar]

Will the series rating still be valid here, since the upstream type JJ feeder breaker is in series with this type JD main breaker.

The series rating between the upstream JJ and the down stream EDB breakers remains valid. However the downstream panel board would not be series rated because of the JD main breaker.

Either remove the JD breaker entirely or replace it with a JJ breaker.