In 1994, my new Townhouse when I lived in Midrand, had an odd "box" just outside the front door. On enquiring with the complex electrician, he advised me that it was designed for a ripple control relay.

This was apparently a device that could be used by the Local Municipality, to switch off just the geysers in a suburb, to prevent maximum demand charges.

It might only be necessary to shed the geysers for 15 or 20 minutes, which would have absolutely no effect on hot water, but have a huge reduction on power demand, given that the average geyser is 3Kw per house.

Went back to have a look. Box still there with loose wires.

What ever happened to that simple principle of load shedding, without the need to shut down a suburb completely.