metering, or, if it will be used for protective relaying. Burden The load, or burden, in a CT metering circuit is the (largely resistive ) impedance presented to its secondary winding. Typical burden ratings for IEC CTs are 1.5VA, 3VA, 5VA, 10VA, 15VA, 20VA, 30VA, 45VA & 60VA with ANSI/IEEE B-0.1,