RCD diagnostics before installation

To eliminate false positives RCD and to make sure it will work at the right time, you need to do the following:

1. Measure the leakage current in the protective zone of the RCD. It should not exceed 1/3 of the rated residual current of the RCD.

2. To measure amperage with electrical appliances turned on at maximum power in that section of the wiring. The rated current for which the RCD is designed must be greater than the value obtained during the measurement.

3. Check the RCD itself, as there are many fakes.

Through the RCD you must pass a current equal to the rated breaking differential current of this instance of the RCD (according to the marking) with a time limit of 200 ms. If the tested RCD trips, this means:

a) The RCD is correctly adjusted, its sensitivity is normal, the disconnection occurs at a differential current equal to the nominal one.

b) The speed of the RCD is sufficient as it trips in a time interval of 200 ms.

The actual tripping time of high-quality electromechanical RCDs is 30 — 40 ms, although the standards specify the maximum allowable time — 300 ms.

Considering that the RCD plays a huge role in your safety, it is imperative to carry out diagnostics before installation!