VEM4 mechanical and electrical interlock unit is used for the interlocking of two AF contactors of the same size: for AF09, AF16-30-/AF26, AF38-30-00/AF09, AF16-40-00/AF26, AF38-40-00. When mounted between two contactors, the VEM4 interlock unit prevents one of the contactors from closing as long as the other contactor is closed. VEM4 set includes a mechanical interlock unit VM4 with 2 fixing clips (BB4) and a VE4 electrical interlock block with A2-A2 connection. Fixing the electrical interlock block to the contactor front face connects the 2 built-in NC interlocking contacts with the two coils. VE4 block must be used with A2-A2 connection to respect the electrical connection diagram.