How to check an RCD for operation?

  • Dec 14, 2020
click fraud protection

The residual current device is a useful and even irreplaceable device that must be installed in absolutely every electrical panel. The RCD operates in the event of a current leakage, stopping the supply of voltage to the line and thus protecting a person from a potential hazardous to life and health. And there are several proven ways to check it, because it must be done periodically.

"Test" to help

On the body of any residual current device there is a special button "Test", when you press which simulates the leakage current, that is, the rated current is forcibly supplied to the RCD cut-off.

Figure 1: Each RCD has a Test button
Figure 1: Each RCD has a Test button

The button is hard not to find, since it is installed on the front panel of the device and has a marking designed for the most inattentive user, as well as a bright color.

How to check the functionality using the "Test" button:

  1. Click on the "Test" button. No protective equipment, for example, gloves, is required - the device body is made of dielectric materials, all operations with the RCD can be carried out with unprotected hands.
    2. instagram viewer
  2. Measure the output voltage with a multimeter or just see if there is electricity in the home.

Professional masters advise to carry out this simple operation with a residual current device at least once a month in order to remain confident in its performance.

Lamp, wire, resistor

It is possible to simulate current leakage with a fairly simple device. To do this, you will need: a lamp with a socket, a park of wire sections with a cross section of at least 1.5 mm2, a variable resistor. The lamp power, for maximum compliance with the nominal operating conditions of the RCD, should not exceed 15 W. A resistor with a resistance of 2.5 kOhm for such a light source will be enough.

Figure 2: Checking the RCD in an unusual way - using a battery

It remains to assemble the circuit:

  • Solder the resistor to one piece of wire.
  • Fix the wire with the resistor to one terminal of the cartridge.
  • Fix the wire without resistance on the second terminal of the cartridge.
  • For convenience, test leads can be soldered to the free ends of the wires.

Now, with one wire, you need to touch the zero entering the RCD, and the second - the outgoing "phase". A luminous lamp will signal the presence of a leakage current, and the residual current device after all actions must "cut off" the network.

The hardest way

It is difficult because you have to assemble a circuit consisting of a lamp, a resistor, a rheostat and an ammeter. The ammeter will show at what actual leakage current the residual current device trips.

The circuit differs from the above only in that the wire with the soldered resistor must be connected to the rheostat, from the rheostat it must be put into phase. And connect the second conductor to one of the multimeter probes. Fix the second probe on the operating "zero" entering the RCD. The multimeter in this case will be the same ammeter.

Figure 3: Checking an RCD with a multimeter

Smoothly increasing the current with the help of a rheostat, you can see at what value the RCD will work. If at nominal, then the device, firstly, is operational, and secondly, it is correctly configured by the manufacturer.