I have come across a concern with regards to article 240.86(C) in the NEC- which indicates that series rating is not allowed when the motor contribution exceeds 1% of the interrupting rated of the lowest rated circuit breaker.

This particular article does not seem to take into consideration if these large motors such as chillers are VFD controlled which to my understanding will limit or not allow any fault contribution onto the system.

Trying to find a separate article which explains this condition.

Thanks in advance for your help.