I had a similar experience with a manufacturer based her in TO.
They insisted in using their own electrician, who was a power/HVAC guy.
Of course he did EVERYTHING wrong
- route the cable through steel conduits
- with power cables
- and past fluorescent lights
And of course the company was doing it all on the cheap so it wasn’t shielded cable!
But the real showdown was that he punched the wires into the rack and the outlets in a completely arbitrary manner.
And guess who got yelled at when the network didn’t work?
When I FINALLY convinced the COO what was wrong he went through with me and we re-routed and re-punched the wiring together. Of course I billed for that time, which he wasn’t happy about.
The moral is that you should do the job properly, which often means getting the experienced professional.