A clamp-on current transformer allows for the measurement of current flowing in a cable without the need to open the circuit. Additionally, it protects the user from hazardous voltages in the circuit. Together with the installation tester C.A 6116, the accessory clamps are used to measure current, selective grounding resistances, power, and for harmonic analysis. The choice of the current clamp to be used depends on the current value to be measured and the cable diameter.