The term "self-contained meter" refers to the standard watt-hour meter or k Wh meter which is commonly used to measure electrical energy use for most residential customers. Standard self-contained watt-hour meters can generally handle currents up to 200 amps and voltages up to 480 volts. If the customers service requirements are larger than this, a standard self-contained meter can still be used, but it must be installed in conjunction with instrument transformers known as CT's (current transformers) and PT's (potential transformers).
Self-contained meters are made to fit in standardized meter sockets. The meter is simply pushed into place in the socket, secured with a clamp ring, and sealed in order to make it tamper proof. They come in both single phase and three phase types.