A major line is down. You and Bob, the only maintenance electricians available, trace the problem back to an 800A breaker. Your distributor doesn’t have a replacement for that breaker in stock and it will take 10 days to get it. They do have the rebuild kit in stock however, and it costs a fraction of what a replacement breaker costs.
The plant engineer says this is a no brainer, order the kit delivered and rebuild the breaker. You’ve never been trained in how to rebuild any breaker, much less this model, and neither has Bob. Should you refuse this job?
Absolutely! You are not “qualified personnel.” Not only would doing that job violate NFPA 70E (and OSHA regulations), any “trainee mistake” would create a hazard for people in the vicinity of that breaker.
One reasonable solution in this situation would be to ask your distributor to whom they have sold that rebuild kit before. You may quickly find someone who is qualified to do that job.