Square D Meter Mains are single phase power distribution panels used in residential applications where local codes require service disconnects to be located outside the dwelling. The meter socket supports a standard utility meter and a main disconnect breaker which provides a time and space saving solution for contractors and installers. Meter mains are surface or semiflush mount with provisions. This is for the field installation of the service disconnect(s) that feed devices downstream. Interior subfeed load centers are typically used with these. This CSED is a QO ring type, class 320 socket with test block bypass, and underground feed. With a current rating of 400A, this product has a short circuit current rating of 25kA. Main lug interior option is also available. Devices meet the Electric Utility Service Equipment Requirements Committee (EUSERC) standards, Federal Specifications W-P-115C for government housing.