On Fri, 23 Mar 2018 09:56:44 -0700 (PDT), Mathew Newton
wrote:

It's just that this time I have to involve BC for the extension (quite rightly IMHO) but I am worried that I won't get the completion certificate without the electrics being formally tested.


The builder extended existing circuits, lighting and power, on my
extension a few years ago. The building inspector was told this and
there was no problem getting the completion certificate.