PE (always learning)
Senior Member
- Location
- Saint Louis
- Occupation
- Professional Engineer
I have a question that pertains to selective coordination and turning off the instantaneous function on a switchboards main circuit breaker. For some projects I have turned off the switchboards instantaneous function in order to coordinate with the down stream breakers. I have not thought about this as much until recently, but could this potentially become an issue if the short time delay is set higher than the 3 cycle short time rating of the switchboard? Would the instantaneous override take care of this issue or would this still be a problem?