Test Blocks facilitates easy in-situ, onload testing of relays, metering and control panels without disrupting load circuit. The housing is robust, high grade phenolic moulding. The terminals are brass, duly nickle plated. The contacts are spring loaded, silver plated and supported by phosphor bronze strips. Each contact is separated with a SRBP shroud. 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.
Relay Test Blocks are also called FT Test Swtiches in other parts of the world