The use of steel conduit seemed to be almost universal in older properties, I can remember assisting my Bro in law rewiring such properties and getting the modern twin and earth in and through the conduit was a real PITA. Power sockets were also a mare as invariably power distribution was hit and miss by means of radial wiring, no such thing as ring mains.
As for the question of where the power came from, well DC was not uncommon so the use of dynamo may well have been the choice of some.
My secondary school in the late 50s was in fact run on a DC system.
Looking back it is terrifying what people did, I still have the image in my head of my Nan plugging her iron into an adapter which was plugged into the lightbulb holder. I can also remember as a teenager going to parties at houses with no power at all only gaslighting. Fortunately for us battery powered record players existed
Phil