When performing a service change the electrician is responsible to verify that each branch circuit he reconnects is in good repair and adequate for the purpose it was installed, at the time it was installed.
so if you want to reconnect a K&T circuit you need to check that there are no 3 wire outlets installed, no light fixtures that need to be connected to 90 degree wire or be bonded. You want to check for extensions to circuits that were done badly too. Check at every device to see the insulation on the wire is still in tact. Only the deficiencies need to be corrected. For a relocated outlet? today's code. Upgrades for outlets where the walls are stripped to bare studs.
That doesn't really happen in Canada - at least in my part of the country.
