Just before all the self isolation and not being closer  than 6 foot to anyone else I had a chat with a couple of DNO engineers who were doing insulation tests on the  HV cables going to/from a sustation at the end of the road the 11Kv cables are tested at 15 Kv to Earth not sure if they used AC or DC. Another thing was the that I never realised just how big the fuse holders for the outgoing LV cables are I asked what size the fuses were and they told me they were 400 amps. I was just being nosey but it's interesting to me to see just where my juice comes from which is a rather scruffy 500 KVA transformer