430.110 Motor Disconnect

[Bob Clukey]

Please help. Is the rating of the motor disconnect based on the FLA motor nameplate or FLC motor Table 430.250?

 

[Gregg Harris]

Please help. Is the rating of the motor disconnect based on the FLA motor nameplate or FLC motor Table 430.250?

FLC of the name plat on the motor

430.250 references the current equivalent HP rating of the motor

 

[Jraef]

FLC of the name plat on the motor

430.250 references the current equivalent HP rating of the motor

Not entirely correct. For almost all calculations in 430, you use the FLC from the tables NOT the motor nameplate FLC, unless the motor nameplate FLC is HIGHER than that shown in the tables, which will be unlikely.

The reason is, no two motors are alike, and no two have the same FLC. So if you used the nameplate FLC on a high efficiency motor, then later in an emergency someone replaced it with a standard motor with a higher FLC, the conductors, switches, SCPDs etc. had been selected using the lower values may end up too low.

The ONLY thing that you consistently use the motor nameplate FLC for is overload heater selection / adjustment.

Read section 4.1 of this NECA guide, and keep it handy if doing motor work, it's a great resource.

 

[iwire]

Read section 4.1 of this NECA guide, and keep it handy if doing motor work, it's a great resource.

Saved it to disk and it is printing now.


Thanks.