Almost for sure that's what happened to the OP as he was having an external disconnect, so the entire panel got depowered + likely big lines were run for whatev

Almost for sure that's what happened to the OP as he was having an external disconnect, so the entire panel got depowered + likely big lines were run for whatever he needed the disconnect for. There's sometime exceptions for Solar now that don't require full upgrades, but some cities don't give a fuck. The US is way worst about this than most other places though. Here they inspect your insulator, lead-in wires, meter, and distribution panel and then ask what if any problems you are having (they is the power company) every four years. Mostly the electrician/contractor does the work and there's no inspection of that.