ESI 50-2 : ISSUE 1 AMD 1

Limited to electrical measuring instruments in which the deformation of a bimetallic element, directly or indirectly heated by a current, is transmitted to the moving element. It specifies requirements for such instruments which measure current on single phase or balanced polyphase ac systems operating at not more than 650V. Applies to such instruments fitted with both maximum and minimum reading pointers or either, in addition to the drive pointer; also to instruments having a position sensing device to detect any movement of the pointer beyond a predetermined deflection. Includes certain integral components used with such instruments e.g. current limiting transformers. Applies to such instruments scaled in amperes, active or apparent 'power', viz: A, kW, MW, kVA or MVA.