Hello,
I charge my trainee (he is already an ITA, now doing a 2nd training as an IT specialist with me) about 60% of my hourly wage in situations where I consider it appropriate. Where he completes the work in the same time as I would (e.g. simple routine tasks), I charge the same rate that I would take.
Regarding the electrical work, I don’t believe it is fundamentally appropriate to charge trainees the "master craftsman’s wage" if the quality is not the same. The OP has already provided examples above.
For example, I recently had most of the electrical work renewed in my old house by 2nd-year trainees (no one else wanted to do it... because it was very old electrical work, electricians looked inside, closed the door again... gone... that’s why...)
After they unfortunately left nothing labeled and did not complete an important supply line (even after several requests), I had an acquaintance (who is a master electrician) do it. He kindly “took pity” but only because I sometimes help him “like that.” The quality of the wiring in the cabinet was “worse” than what a journeyman/master would have done. That’s his opinion. Experience was simply missing. But I also didn’t pay a master’s wage and therefore am not allowed to complain. They probably also took twice as long as a journeyman with more experience?!
Here I think the result counts. If it is a bit worse:
.... Forgot cables, switches too close to doors, etc. He also confirmed to me that he hadn’t understood electronic plans for the kitchen or heating....
then it is impossible to demand the same price for that or to generally reduce the invoice because of the existing defects (if those are indeed “real” defects).
zapp