The Encapsulated Chassis 18P is a top feed chassis with a 400 A capacity and a pitch of 27 mm. It has a withstand rating of Icw 25 kA/0.1s and 10 kA/1s, as well as an Icc rating of 30 kA. The incoming terminals are made of 3 mm thick copper, while the base is made of 1.2 mm thick galvanized iron. The chassis is coated with duravin SCI-TV, making it suitable for S800 breakers in the IA range IPD.