Transformer Secondary Protection

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tyha

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central nc
feeding a small tenant space withing an airport. the service was supposed to be supplied with the shell so the drawings do not show anything but to connect to it and install our new panel. well it isn't there and the general wants us to price doing it. we are going to install a 50amp 3p cb in a 480v panel. run to a 30k x-fmr in the same electrical room. the panel in the tenant space is mcb but do I need to install an enclosed breaker inside of the electrical room. will the tenant space panel that is about 70 or so feet down the hall not qualify as secondary protection.
 
tyha said:
feeding a small tenant space withing an airport. the service was supposed to be supplied with the shell so the drawings do not show anything but to connect to it and install our new panel. well it isn't there and the general wants us to price doing it. we are going to install a 50amp 3p cb in a 480v panel. run to a 30k x-fmr in the same electrical room. the panel in the tenant space is mcb but do I need to install an enclosed breaker inside of the electrical room. will the tenant space panel that is about 70 or so feet down the hall not qualify as secondary protection.
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Sounds fine as long as it is sized correctly for the wires and transformer.
 
Transformer protection is only one item to consider.

Your 75' of indoor cable is not protected per 240.21(C).
 
jim dungar said:
Transformer protection is only one item to consider.

Your 75' of indoor cable is not protected per 240.21(C).
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It, in effect, becomes a tap conductor issue then right?
 
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