Is secondary ocp required when primary protection is right next to this load?

[alblock]

Powering a stand alone air compressor with a 3 phase 15hp 200v fire pump motor. There is no disconnect on this compressor. The wires terminate at the motor starter.

We have an extra 480/208 45kva delta wye transformer that I can put right next to a disconnect that's not being used but has power and change to 70 amp fuses. They will be side by side. The compressor will sit 10ft or less away from the transformer.

Is another secondary ocp required?

 

[kwired]

Powering a stand alone air compressor with a 3 phase 15hp 200v fire pump motor. There is no disconnect on this compressor. The wires terminate at the motor starter.

We have an extra 480/208 45kva delta wye transformer that I can put right next to a disconnect that's not being used but has power and change to 70 amp fuses. They will be side by side. The compressor will sit 10ft or less away from the transformer.

Is another secondary ocp required?

Please clarify the order of things.

I am understanding 480 volt switch with 70 amp fuses>>>45 kVA delta/wye transormer(208 volt secondary)>>>15 HP motor.

If that is correct, I think you need secondary overcurrent device because of the wye secondary.

If it were delta to delta transformer you could protect secondary conductors via the primary overcurrent protection, but for a 15 HP motor you would be looking at 40 amp max fuse (on the 480 volt side) for motor circuit SCGF protection.

 

[alblock]

Please clarify the order of things.

I am understanding 480 volt switch with 70 amp fuses>>>45 kVA delta/wye transormer(208 volt secondary)>>>15 HP motor.

If that is correct, I think you need secondary overcurrent device because of the wye secondary.

If it were delta to delta transformer you could protect secondary conductors via the primary overcurrent protection, but for a 15 HP motor you would be looking at 40 amp max fuse (on the 480 volt side) for motor circuit SCGF protection.

Yes that's correct. Thank you