If the amount of current going into the electrical installation is greater than the current going out, there is leakage current. Electrical wiring and electrical components are usually insulated or shielded. The insulation or shielding ensures that an installation is safe and that the housing of the machine or device cannot be undesirably live. In addition, the insulation of electrical wiring and electrical components ensures that the leakage of current is prevented. A leakage current can be caused by damage to the insulation or a defect in an electrical device, which unexpectedly applies voltage to the entire device. Therefore, if you have connected any power manager in the system, leakage current may disturb its performance. With class 1 equipment, this leakage current will flow through the earth, causing a potential difference and tripping the RCD. In addition, harmonics can also send a current through the grounding conductor and trip the RCD. To solve this problem, you will need to detect in which part or parts of the device/installation the harmonics are located.
Fix errors
When the earth leakage circuit breaker trips, you can use a leakage current clamp to make clear where the problem or several problems are located. The procedure is as follows: make sure that the installation is not used by other people to avoid dangerous situations. Sometimes it is necessary to bridge the earth leakage circuit breaker temporarily for the purpose of the measurement. Now we measure the phase and neutral of the individual groups simultaneously with the leakage current clamp (this is the differential current that the RCD also detects). When we have identified the group with the leak, we go further and further into the installation, measuring the phase and neutral at the same time again and again, until we have identified the problem. Do not forget to return the earth leakage circuit breaker to its original condition after solving the problem.
How do leakage current clamps work?
Leakage Clamp Meters are high-precision AC clamp meters, with resolution in the milliamp range. This makes it possible to visualize the very small leakage currents. This is done by directly measuring the ground wire or by measuring the phase and neutral simultaneously. Leakage current clamps from Kyoritsu, for example, have a 50/60Hz filter, which you can use to rule out whether the leakage current is caused by harmonics.
Conclusion
The most common cause of leakage current is a physical leakage from phase or neutral to ground due to moisture or poor insulation, but it can also be caused by harmonics. Various leakage current clamps allow you to detect the leakage current by measuring the phase and neutral simultaneously or measuring only the ground wire. By means of a built-in filter you can find out whether the leakage current has a physical or harmonic basis.
