C1 C2 low probability strike Circuit Breaker

[aquashot]

Dear Colleague,

For the medium voltage circuit breaker, said around 30kV, that feed to harmonic filter (reactor and capacitor bank), is there any provision for the CB?
(There is only disconnecting switch between CB and harmonic filter)
I am confused, must CB be C2 class? Any reason ?
Could it be C1 class?
Is there any electrical standard document that clearly mention C2 or C1 on this case?

C1 : low probability of restrike
C2 : very low probability or restrike

Thanks for any kind response
Aquashot