What Is an Electronic Leak Detector?
An Electronic Leak Detector is a device that emits a sound or signal to alert the user in the event of an electrical leakage.
Electrical wiring may be subject to insulation deterioration due to the insulation coating peeling off as a result of disasters or age-related deterioration. When this occurs, sparking between the exposed core wire and the building frame generates heat, and wiring with an organic insulation coating can easily catch fire.
Electrical fires are often caused by the above causes. Electronic Leak Detectors are installed for the purpose of preventing such fires.
Usage of Electronic Leak Detectors
Electronic Leak Detector installation standards for buildings are generally using lath mortar.
Lath mortar is a structure in which mortar is spread around a metal mesh called metal lath. Thin metal mesh has a low allowable current and low grounding resistance, which increases the risk of fire.
Even when lath mortar is used, the installation may be exempted if the contract current is low or the total floor area is small.
Principle of Electronic Leak Detector
Electronic Leak Detectors are designed to detect ground-fault currents and to alarm when a certain power system is not normally supplied with power.
When a power system is feeding power normally, the sum of the currents on the distribution lines is always zero. This is true for both three-phase and single-phase systems. In electrical engineering, this is called a balanced state. In a balanced state, the sum of the magnetic fields around the wiring feeding a single system is zero, and the change in the currents around the system due to the magnetic fields is 0A.
However, when a ground fault occurs and a ground fault current flows, the equilibrium state is disturbed and the sum of the magnetic fields of all phases is no longer 0. ZCT is a device that clamps all phases of wiring together and detects currents flowing out of equilibrium.
Electronic Leak Detectors receive the earth fault current value from the ZCT, and if the value exceeds a predetermined threshold value, the alarm is triggered. Since it only emits an alarm, it has no interrupting capability against leakage current. For leakage current fire protection, a separate switchgear or RCD must be installed.