Auxiliary Contact Mounting Frame Required to mount 'Standard Auxiliary Contacts' to the 'Mini OS Fused Switch Disconnectors' Simply clips to the left hand side of frame Two rows of 3 'Standard Auxiliary' contacts can be fitted (e.g. type OA1G10 stock no. 513-4350 ) ABB OS Range A fused switch disconnector provides a cost effective means of short circuit protection, together with circuit isolation. The choice of fuse rating determines the level of protection, the maximum value is determined by the fused switch disconnector. These items have been tested in accordance with EN 60947-3.