musty wrote:
Hi,
I need a little bit of info about the wire sizing for upgrading a
10 hp motor to a 15 hp motor. The present system uses a 30 amp
protective circuit. The 15 hp motor is rated @ 23.7 max amp. The wiring
is 8 gauge. Please tell if a direct swap in motors is likely. nb the
voltage is 3 phase 460 volts.

The #8 wire is OK, the 30A protective device is not.

You need a 40A protective device.

If the protective device is a fuse, then you will have to change to a
60A fuse block to accept the 40A fuse.

If the protective device is a c'bkr, then you will have to change the
c'bkr.

You will also have to change the motor starter from a NEMA size 1 to a
NEMA size 2 complete with the proper overload heaters.

Lew