VFD Overcurrent Protection

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jbond

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How do you appropriately size a breaker/fuses that are feeding a VFD? I am driving a 0.5HP motor with a 3HP VFD. My thought is that the breaker/fuse size would be sized to accomodate the VFD.

I have seen in the past where the VFD manufactures give a recommended fuse size but I am looking for reference in the code. Do I use the input current rating of the VFD?
 
The code specifies that the conductors feeding the VFD be sized at 125% of the input amps, but does not specify the OCPD size.
 
I would call the manufacturer of the VFD for their recommendations. Usually it is only to protect the wire from faults and not the VFD. Sometimes (rare) a high speed overcurrent protection device is recommended.

Just my $.02 (adjusted for inflation)
 
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