A metering box is the complete assembly of measuring instruments and auxiliary equipment required for electrical energy measurement, including electricity meters, voltage and current transformers for metering and their secondary circuits, metering panels, cabinets, and boxes.

       Metering boxes can be installed in either suspended or floor-mounted configurations. To ensure installation quality, suspended boxes must be secured using built-in expansion bolts, with bolt dimensions meeting safety, stability, and outdoor installation requirements.

      Direct connection types must include an incoming line switch compartment, a metering compartment, and an outgoing switch compartment; transformer-connected types must include a line switch compartment, a transformer compartment, a metering compartment, and an outgoing switch compartment. Each functional area must be independently separated. Electricity meters and power information collection terminals should be installed on fixed clamps, mounting racks, or panels. The horizontal distance between electricity meters should be no less than 30mm, and the vertical distance no less than 80mm. The distance between test terminal blocks, electricity meters, power information collection terminals, and the enclosure should be at least 60mm. The distance between the front face of the electricity meter and the observation window should be between 15-20mm.

       Altitude: <1000m; Ambient temperature: -10 to +45°C; Extreme operating temperature range: -15 to +55°C; Relative humidity: at +20°C, not higher than 90%; at +45°C, not higher than 50%; Protection rating: outdoor not lower than IP34D, indoor not lower than IP20; Rated voltage: below 500V; Rated current: single-phase or three-phase direct connection, load current per household not exceeding 40A; Rated insulation voltage: 660V; Frequency: 50Hz; Grounding method: TT, TN.