vfd protection of cable

[hhsting]

I have a question. On below VFD drive the ouput cable is 4#10 awg. What is protecting that output cable? Does the engineer need to provide output protection size or is it protected by the 15A fuse?

 

[bwat]

See 430.124... specifically 430.124(A)

Also 240.4 and then 430.22

 

[infinity]

Why 4 conductors?

 

[hhsting]

By output conductors I meant the conductors between the VD and the Filter pump disconnect. What is protecting them?

 

[ptonsparky]

In 2". That should be easy enough to pull.

 

[hhsting]

See 430.124... specifically 430.124(A)

Also 240.4 and then 430.22

I dont follow. If no overload protection require then how do you size them and what protects them?

 

[bwat]

I feel like you didn't read the sections I posted. 430.22 shows how to size them.

The drawing posted looks like there are three things that could be providing protection. The 25A CB, the 15A fuse, and the VFD.

 

[ptonsparky]

I dont follow. If no overload protection require then how do you size them and what protects them?

No additional overload protection is required.

 

[don_resqcapt19]

All of the conductors are 10AWG...the OCPD at the beginning of the circuit is 25 amps....the conductors are all protected below their ampacity by the 25 amp breaker.

 

[tom baker]

The VFD has internal overload protection in the software. Also, it will have ground fault, protection, built-in. Once you set the motor follow the amperage and the service factor, the VFD software will not let that current be exceeded.

 

[infinity]

Given that the motor FLA is 7.5 amps couldn't the conductors between the motor and the drive be #14 AWG?