Like a normal contact insert, the new system of modular contact inserts pluscon hcm from phoenix contact is screwed in housings of heavy, rectangular industrial plug connectors. It is composed of the most diverse metal holding frames and contact insert modules for the joint transmission of electrical signals, power, pneumatics and high frequency. The new wiring concept, in other words the combination of plug connectors and different contact inserts in one housing, is much more economical and flexible, as all contact insert modules can be combined as desired. The modules are tested according to the us standard ul 94 vo. The robust structure allows the application in the most harsh industrial environment.