Changing existing air compressor

[Davebones]

Have a existing 250 amp I-line breaker feed to air compressor .New air compressor only requires 200 amp circuit . If we add 200 amp fusible disc at new compressor fused at 200 amps would we have to change out 250 amp I-line breaker to a 200 amp????? Would this fall under a tap rule????????

 

[LarryFine]

If we add 200 amp fusible disc at new compressor fused at 200 amps would we have to change out 250 amp I-line breaker to a 200 amp?????

Nope. The feeder is still protected by the same breaker that protected it before.

 

[ultramegabob]

the breaker is protecting the feeders, the fuses are protecting the compressor where you reduced off of the feeders, I dont see anything wrong as long as you size your wire properly....

 

[augie47]

Just for fun, let me play devil's advocate here.

Lets assume the original circuit was figured for a motor load.
For fun, a 75HP motor.. 480v 96 amps 120 amp branch circuit (#1) and the 250 amp breaker. (The breaker was the first overcurrent device so this is a branch circuit)

On the new compressor we add the fusible switch which becomes the branch circuit protective device. The original branch circuit is now a feeder. We have a #1 THHN feeder supplied by a 250 amp breaker.

Code Compliant ??

I've seen this approached more than 1 way in my life.