Zellweger Off-peak

Zellweger Off-peak

Zellweger is the brand name of an electric switching device used to switch off-peak electrical loads, such as off-peak hot water, on and off. Power stations transmit a ripple on the main transmission lines when off-peak rates start (often around 10 pm). This ripple noise is picked up by the Zellweger, which after a random delay turns the hot water heater on. The noise is often picked up by other equipment, especially audio amplifiers and stereos and the noise can cause problems with other electrical devices. Even some telephone lines can pick up the noise. The noise can be particularly obtrusive from some fluorescent light systems.

Newer electrical meters incorporate this technology into the meter. "Time of use" meters charge electricity to the current tariff within half an hour, giving customers incentive to run appliances such as dishwashers, pool pumps and clothes dryers during the night.