Additions or alterations to lift or escalator or moving walk installation

Additions or alterations to lift or escalator or moving walk installation. No additions or alterations, which cause any change in the characteristics of lift or escalator or moving walk like change in passenger capacity, speed, stops, steps, etc., or other than those required to be made under section 21, shall be made to any lift or escalator or moving walk installation except with the prior permission in writing of an Electrical Inspector (Lifts).