Ground Fault Protection for Separately Derived System

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FDSENG

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Da UP
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Engineer
A customer has recently become Primary Metered, and their old "service" is now a separately derived system. The existing system is ungrounded, 480 delta, 1,600A disconnect (with 1,200A fuses). There are no feeders or branch circuits originating from this bus that are 1000A or greater. We are keeping the existing fused disconnect switch and fusing, but replacing the transformer (and the MV system that feeds it). So here is the question: Do I need to have the existing fused disconnect switch retrofitted with a ground fault protective device? The utility IS requiring the new transformer to provide 480Y277VAC from the 12,470 system, so the new separately derived system IS solidly grounded (you guys already helped with the bonding location, thanks).

230.95 doesn't apply, because this isn't a service, correct?
210.13 doesn't apply, because this isn't a branch circuit, correct?
Does 215.10 apply? The definition of a feeder is "all circuit conductors between the ... source of a separately derived system ... and the final branch-circuit OCPD."

Thanks!
 
215.10 does apply to the OCPD on the load side of your transformer. The only way to get around this would be to use multiples sets of transformer secondary conductors and multiple secondary OCPDs rated less than 1000 amps.
 
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