Emergency Loading. The emergency capability of the equipment in which the bushing current transformer is installed is first calculated. With this value as a base, apply the applicable principle outlined in Section 3.2.1, above, to determine how the emergency capability of that equipment should be modified, because of the current transformer. EXTERNAL BUSHING CURRENT TRANSFORMERS These are current transformers that use the current-carrying parts of major equipment as their primary windings, and are not usually purchased as integral parts of such equipment. Such current transformers are to be assigned ratings in accordance with the manufacturer’s recommendations. DEVICES CONNECTED TO CURRENT TRANSFORMER SECONDARY CIRCUITS In all cases where current transformer secondaries may be loaded in excess of 5 amperes, a careful check should be made of the effect this will have on the devices connected in the secondary circuits, with respect to both accuracy and thermal capability. Refer to Appendix K, Current Transformer Circuit Components for accepted practices for determining ratings of such equipment.
