Scope and Purpose These specifications are intended as a reference for purchasers and users of circuit breakers in the preparation of requests for quotations and as a reference for manufacturers and vendors in submitting bids. These specifications apply to all types of alternating- current power circuit breakers (indoor and outdoor) having an interrupting rating of 50 mva or higher and a voltage rating above 1500 volts. Individual clauses apply to all types except where otherwise indicated. These requirements of necessity include some elements of construction and materials@ but are not intended to preclude ingenuity of design or improvement.