It specifies current sensing coils of the toroidal-coil type as a current sensor for welding current meters or a welding current measuring system used to monitor the welding current in resistance welding, and is applicable for both current types, i.e. alternating current of 50 Hz or 60 Hz and direct current.
BS ISO 17657-3:2006 history
2006BS ISO 17657-3:2006 Resistance welding - Welding current measurement for resistance welding - Current sensing coil