Accessory DIN rail mounting for 4NC51 plug-in current transformer 4NC. The plug-in current transformers are used for primary nominal currents from 40 A to 3000 A, secondary nominal current 5 A or 1 A and in classes 0.2S, 0.5 and 1. They are also suitable for measuring functions with PAC and AI Energy Meter due to better accuracy and are used in mechanical engineering, especially for new systems with medium electrical power or in plant engineering.