The single-phase wall mounted STS prepaid energy meter is exported to the African market, and the power wiring method is LNNL, which meets the requirements of the African market. The case material adopts flame retardant PC, which has high case strength and anti-aging. Prepaid electricity meters, pay first and then use electricity, effectively solve the problem of charging difficulties; Overcurrent automatically cuts off the power supply to protect the safety of the wire.