The housing of robust, high grade phenolic moulding, capable of long & trouble free performance in varied climatic conditions. It is designed and manufactured for indoor application. The terminals are brass, duly nickel plated. The contacts are spring loaded, silver plated and supported by phosphor bronze strips. Each contact is encapsulated separately in a module. Screws are provided at the rear for terminations. Alternatively, studs with nuts and washers could also be provided. Sealing holes on cover studs are provided to prevent unauthorized access. The front Cover can be removed for test purpose and replaced, thereafter. This Cover is fitted with a silver plated Contact finger to close the trip contact, when inserted. Otherwise, the trip contact would remain open. Thus the contact finger on the Cover, completes the entire circuit. Isolation of the trip circuit is feasible by removing the contact finger fitted to Cover, thus avoiding unwarranted tripping under test conditions.