ELCB TESTER
1811 EL is a Digital ELCB Tester TEST DISCONNECTION SENSITIVITY (mA) TEST DISCONNECTION TIME (ms)

Taut Band movement, Wiring Check, Robust, Simple Operation, Can be used on 2 wires L-E(ELCB/RCCB/GFCI tester), Can be used on 3 wires L-E-N (with wiring check), No batteries, Sense automatically 50 or 60Hz.
Current injected in phase with the voltage.