This ring core is designed for the Vigilohm insulation fault location devices and the VigiPacT type A residual current protection and monitoring relays. It allows for the monitoring of the fed component from the Vigilohm Insulation Monitor and the measurement of a rated current up to 160 A for VigiPacT monitoring and protection relays. The transformation ratio is 1/1000. The inner diameter of the toroid is 80 millimeters, and the weight is 0.9 kg. The cables must be centered within the toroid, and the diameter of all these cables must not exceed 40 mm. The maximum cross-section per phase (R, S, T, N) is 95 mm² for a copper conductor.