I work for a utility that has off-peak metering using two meters. The off-peak meter has a timeclock and built in 30 amp 2 pole relay to control the lower element of the hot water tank. As for the installation, we require a licensed electrician, working for the home owner, perform all electrical work for our off-peak metering, including providing and wiring the meter sockets.
The off-peak system we use, saves the customer approx 40% of the cost to heat their hot water.
