... accuracy class of the calibrated electric energy meter. 9. Measure CT variable ratio, ratio error, angle error and polarity. 10. ... , according to demand, select clamp meter with 5A, 10A, 100A, 200A, 500A, 1000A, 2000A current span or flexible coil mutual inductor to ... . Extended measurement: PT secondary voltage drop, PT secondary load, CT secondary load. 24. GPS interface is reserved, which can conduct ...