The 48 x 48 selector switches are designed for flush-mounted installation on doors, wicket doors and front plates of enclosures and cubicles. The voltmeter selector switch uses a single voltmeter for successive measurement of the voltages (phase-to-phase and phase-to-neutral) of a three-phase circuit. Electrical durability of 100,000 operations, and mechanical durability of 2,000,000 operations. This product is calibrated for 500V network. 7 silver-nicket contacts for phase 1, 2, 3, phase 1 to neutral, phase 2 to neutral, phase 3 to neutral or none. Complient to standards IEC/EN 60947-3. Ingress Protection IP65 on front, and IP20 on the back at terminal level. Product dimensions are 48mm in height, 48mm in width and 93mm in depth. Embedded depth behind a door, 66mm.