These DBs come with built-in pre-wired phase changeover switches. These are 40 A, 4 Way TPN, built-in DBs. Detachable Din rail assembly and intermittent door facilitates ease in Wiring during installation and maintenance. DBs are subjected to seven tanks Process and treated with Premier quality powder coating. Cement Masking Sheet protects the DBs against extreme site conditions.DBs are supplied in Dual Packing for safety during transit and storage.