reducing of motor wire size

[malachi constant]

Hi all, we have a motor being replaced with a smaller unit. The existing unit was fed with #8s from a 40A breaker. The new unit is smaller and the contractor proposes reusing the breaker and wire, with a new disconnect fused at 15A being installed at the motor. I don't have detailed information on motor size. Assuming the 40A breaker is too large of OCPD for the motor, is it legal to fuse down like that at the motor? This strikes me as a "tap rule" crossed with "motor rules", both of which are out of my wheelhouse beyond the basics, and confound me.

It was our suggestion that they swap out the 40A breaker with a smaller 15A breaker, but the contractor states the panel is older and they do not think they can find a replacement breaker in a timely manner. (I bring that up to head off the common sense suggestion.)

 

[don_resqcapt19]

There is no code or technical issue doing what the contractor has proposed. There is no tap rule issue as all of the conductors are protected at their ampacity.

 

[malachi constant]

Makes sense - conductors are each appropriately protected, so no issues. Thank you!

 

[LarryFine]

As Don said, there is no tapping going on, you'll have a feeder now.

You could actually put a sub-panel at the load end if you wanted to.