KYZ is a designation given to a relay used to create pulses for electrical metering applications. It is commonly a Form C relay. The term KYZ refers to the contact designations: K for common, Y for Normally Open, and Z for Normally Closed. When incorporated into an electrical meter, the relay changes state with each rotation (or half rotation) of the meter disc. Each state change is called a "pulse." When connected to external equipment, rate of use (kW) as well as total usage (kWh) can be determined from the rate and quantity of pulses.