Surge arrester 3EK7 for medium voltage networks for outdoor use arrester standard, Ur=15 kV, Uc=12.0 kV rated leakage current 10 kA arrester class, DH Ures (10 kA, 8/20) = 39.8 kV charge transfer rating 0.4C thermal rated charge transfer rating 1.1C rated short-circuit current 20 kA creepage distance 485 mm height 200 mm short-term load