Safety disconnect, VFD and arc flash

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Sebastienc

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Ottawa, Canada
We have a VFD (about 100A, 600V) controlling a motor. This VDF is designed to be directly mounted on a wall and we have a safety disconnect switch located to the left of it (about 18in between them). Therefore the disconnect handle is located between the disconnect switch and the VFD.

An operator questioned the setup, suggesting that when switching on the safety disconnect, he would essentially be standing in front of the VFD, therefore exposing himself to an arc flash risk. The VFD does not start the motor automatically when powered up.

Where can I look for information about this? Or what are the standards that apply?

Thanks for the help.

Seb
 
Are you under the CEC or are you using the NEC. Most of us here are NEC people but there may be a few who know the CEC
 
Sebastienc said:
I'm under the CEC but any info from the NEC will likely point me in the right direction, at least for research.
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As long as working clearances are maintained this is not covered by the NEC (NFPA 70), it is a design issue.
Like wise, this is not outlined in Electrically Safe Work Practices (NFPA 70E) as it is up to each employer to develop their own specific safety procedures.
 
Is the disconnect on the line side or the load side of the VFD?

The amount of current that can get through a VFD in a short circuit condition is pretty limited so IF it is on the load side there may be very little risk of arc flash.
 
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