Leakage current: disease of old wiring. Why is it dangerous and how to find it?

  • Dec 14, 2020

The simplest diagnostics of electrical wiring that you can do on your own is to determine the leakage current. This requires a minimum of tools and almost the same amount of knowledge.

What is leakage current and what does it lead to

Leakage current Is the conversion of electrical energy into another type of energy that does not have a beneficial effect. For example, a slight heating of the wires is not beneficial, but it consumes electricity.

Interesting! The algorithm for finding current leakage given in the next paragraph can be used not only in the wiring of an apartment or private at home, but also... in your own car, where it is so necessary, because a constantly working glove compartment lamp can plant battery.

Leakage results in high energy consumption. For example, a pinched cable creates additional resistance, to overcome which the current must be higher. The location of the damaged conductor heats up and consumes energy for useless, minimal heating of the environment. And with strong heating, it can lead to a fire.

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Figure 1: Old or damaged wire insulation - the first cause of current leakage

Leakage current detection

The algorithm for finding current leakage involves the use of a clamp meter, but you can also use a simple multimeter (best with a fuse provided by the device design).

Leakage current search sequence:

  1. Make sure that all machines are on, and all consumers, on the contrary, are off.
  2. Turn on the device and grasp the phase wire with pliers, measure the readings.
  3. Grasp the neutral wire with pliers and also measure the readings.

The rated current when the consumers are disconnected should be no more than 10 mA. If this figure is too high, then it is necessary to look for a specific leak location. This can be an electrical appliance, damaged insulation on a wire, or an unreliable twist.

Figure 2: Resistance measurements in a junction box, which also helps to find leakage current

Buying a clamp meter for a one-time search for current leakage is impractical. But a simple and inexpensive multimeter can be useful both in an apartment or house, and when repairing a car. To find the current leakage with a multimeter, you must first disconnect the wire from the attachment point, touch it with one probe, and touch the second one to the very attachment point. Thus, an open circuit occurs, and the multimeter operates in ammeter mode.

A few tips for eliminating current leakage

So that such a problem as current leakage does not bother conscientious owners, it is best to check all connections in sockets, switches, on lighting sources, and then in junction boxes. A poor connection is the first cause of current leakage and unwanted heating of the conductor.

Figure 3: Finding current leakage on the washing machine body

So that the fall of the phase wire onto the body of the electrical appliance (which is also a current leak) could not it is necessary to harm the residents of an apartment or house, the hulls of all washing machines, boilers, hobs ground. Or use a zeroing scheme, which is also quite effective. The best option in this case is the installation of an RCD, which is quite inexpensive, because you should never save on safety.