A residual-current device (RCD) is the most important protective device for personal safety in an electrical installation. Normally, the current going out and coming back in a circuit is equal. But when a leak occurs, for example current escaping through damaged cable insulation or a wet appliance, this balance is broken. The RCD detects the difference and cuts the circuit in less than thirty milliseconds.
The current level that is dangerous to the human body is around thirty milliamperes. That is why RCDs used in homes must have a sensitivity of thirty milliamperes. In industrial facilities, three-hundred-milliampere values are used for fire protection. Always choose the thirty-milliampere type for your home.
There are a few critical points to watch when installing an RCD. The device must be fitted in the distribution board after the main switch and before the line breakers. A properly working earthing line is essential for the RCD to trip correctly. In an installation without earthing, an RCD gives only partial protection.
Testing whether an RCD works properly is very easy. Just press the test button marked T on the device. When the button is pressed, the RCD should trip and cut the circuit. We recommend doing this test once a month. If the RCD does not trip when you press the test button, the device is faulty and must be replaced immediately.
RCD protection is mandatory in areas where contact with water is possible, such as bathrooms, kitchens, laundry rooms and gardens. It is also recommended in children's rooms for extra safety.
There are RCDs of different brands and types on the market. A type A RCD detects both alternating-current and pulsating direct-current leakage and is the best choice for homes with modern electronic devices. By choosing quality, certified products you can keep your family safe.
