QO All in One meter mains devices are single phase power distribution panels ideal for residential use for when the local codes require the service disconnect to be located outside the dwelling. These devices come with a meter socket that supports a standard utility meter and a main disconnect breaker and include provisions for field installation of service disconnect(s) to feed downstream devices. Square D meter mains products are single compact solution provides a time and space saving solution for contractors and installers as well as meet a wide range of applications in use today. This meter main is designed for QO range, and is rated at 400 A. This device has a lever bypass type, uses a ringless meter socket type and can be service feed either overhead or underground. This CSED uses AWG 4 to 600 kcmil and AWG 1/0 to 350 kcmil in aluminium and copper.