NEC 408

[OCPD]

The NEC Article 408.36(B) provides guidance on panelboards supplied through a transformer. What about the equipment considered as a switchboard by the manufacturer does it also require similar protection when supplied through a transformer (with an exception of a service entrance)? I could not find an article for switchboard overcurrent protection.

 

[electrofelon]

The NEC Article 408.36(B) provides guidance on panelboards supplied through a transformer. What about the equipment considered as a switchboard by the manufacturer does it also require similar protection when supplied through a transformer (with an exception of a service entrance)? I could not find an article for switchboard overcurrent protection.

Switchboards do not require protection at their rating by an OCPD like panel boards do. However if this is served by an SDS, you will likely need an OCPD somewhere to satisfy 450.3 and 240.21(C).

 

[don_resqcapt19]

The switchboard does not need line side protection, but the secondary conductors have to be protected per one of the rules in 240.21(C).

 

[OCPD]

Switchboards do not require protection at their rating by an OCPD like panel boards do. However if this is served by an SDS, you will likely need an OCPD somewhere to satisfy 450.3 and 240.21(C).

Thank you for the response. What does the 'SDS' acronym mean?

 

[infinity]

Thank you for the response. What does the 'SDS' acronym mean?

Separately Derived System. From Article 100:

Separately Derived System. An electrical source, other than a service, having no direct connection(s) to circuit conductors of
any other electrical source other than those established by grounding and bonding connections.