I just watched that Youtube link " Single wire through metal holes " The guy passes the live meter tail through a 20mm hole and back out again , with an ammeter on it and a temperture probe on the metal . basically , nothing detrimental occurs but thats not actually what happens . In real life it would be the live through one KO and the Neutral through the next ....which is what we are warned not to do.
Also instructed NOT to a single Live or neutral in a steel conduit for the same reasons .
Years ago we used to do a lot of , either large single core PVC or large single core Pyros entering panels etc and as the apprentii we were given the job of putting a hacksaw cut between all the holes or making a new plate from aluminium or brass.
These were 3Ph supplies but I the same occurs between L& N .
I don't think any eddy currents are created as on the Youtube video but I would stand corrected .
I have a post on here which describes meter tails on a 3Ph X 200A supply , clipped to a tray, about 25mm apart instead of trefoil. They created an induction field that extended about 1 mtr , through a block wall and caused interference across some office PC monitor screens . Moved the screens by 1 mtr and they were fine .
The staff refused to sit at that wall until it was sorted.
Edit: I thought they were hinging the doors in the top position to ensure they were not left open to stop all the fireballs from exploding out of the front !
