downsize feed

[wireday]

I have a 30 amp breaker feeding a 30 amp fused disconnect that feeds an air compressor. The air compressor is being downsized needing 20 amp feed.
Do I need to down size the 30 amp breaker to a 20 amp, and lower the fuses in the disconnect to 20 amp

 

[augie47]

Unless the compressor specifically calls for "fuse protection". either one

 

[ron]

The 30A breaker is protecting 30A worth of wire. It can be a 30A breaker or 20A.

The fused switch protects the 30A worth of wire and the compressor, so if the MOCP for the compressor is 20A, you can reduce the 30A breaker or fuse to 20A to protect the weak part of the system which is the compressor.

 

[LarryFine]

Do I need to down size the 30 amp breaker to a 20 amp, and lower the fuses in the disconnect to 20 amp

No to the first question, yes to the second.