tomb53
Member
- Location
- Uxbridge, MA USA
I am constantly getting questions about group installation per 430.53 from my German counterparts (they call it "group fusing"). This chapter does not specifically use the term VFD so it has to be interpreted from the context. My sense is that since the VFD performs motor starting, control and overload functions, it can be substituted in 430.53(C) for "motor controller(s)" and "overload device(s)". If so, it would be considered as a "listed factory assembly" of these components. The motor branch-circuit short-circuit and ground-fault protective device (fuses and/or breaker) is specified in the VFD manual which qualifies as a marking per UL508C and UL 61800-5-1. Is this a valid interpretation?