Testing an RCD in a Dutch home: what the test button checks

If the RCD fails to switch off during the prescribed test, arrange an investigation. A successful button test also has limits: it does not establish the safety of the whole installation.

In the Netherlands, an RCD is usually called an aardlekschakelaar and the consumer unit a groepenkast.

Identify the device before operating it

A consumer unit may contain several kinds of device.

• A circuit breaker protects a circuit against overcurrent, including overload and short circuit.
• An RCD responds to an imbalance between the current flowing out and returning.
• An RCBO combines those protective functions.
• A main switch provides switching within the installation's intended arrangement.

Appearance varies by manufacturer. Look for T or Test and identify the model and its instructions. Colour and width alone do not reliably identify the device.

Enexis lists operating accessible switches and the RCD test button as ordinary user activities. Work behind protective covers requires a different approach. Enexis: work in the meter cupboard.

Prepare for the interruption

Choose a time when a temporary power interruption will not cause danger or damage. Tell other occupants, save computer work and consider equipment that needs restarting afterwards.

If medical equipment, an alarm or another essential service depends on power, agree appropriate continuity arrangements with the responsible supplier or person first. If you have an unfamiliar backup or battery installation, have its operation explained before testing.

Keep the consumer unit closed and make sure its normal controls are dry and accessible. Stop before testing if there is moisture, damage, excessive heat, smoke or a burning smell. The test button is not a method of investigating those conditions.

Follow the manufacturer's user-test procedure

1. Read how the test must be carried out and which operating conditions it requires.
2. Operate the accessible test button as instructed.
3. Check that the RCD switches off.
4. Restore it according to the instructions and check that normal user functions return.
5. Record the date and result.

Liander describes this button test and advises calling an installer if the installation does not switch off. Liander: checking an RCD.

If the device will not remain on or a fault returns, avoid repeated resets. Record what happened and arrange an investigation. Keep covers in place and never force a switch to stay on.

How often should you test?

Use the interval in your device's instructions. Hager explains that manufacturers can specify different testing intervals. A reminder when the clocks change may be convenient, but it is not automatically the correct schedule for every device. Hager: RCD testing.

A simple record needs the make, model, location, prescribed interval, last test and result. If you have several RCDs or RCBOs, keep a separate entry for each. Testing one does not check the others.

For example, two devices with different manufacturer instructions should not be combined into a single “consumer unit checked” tick. Record the result against the device that was actually tested.

What the button test does not establish

It does not measure the continuity of every protective conductor, the condition of insulation or whether all protective devices suit their connected equipment. Instrumented checks of trip times and fault protection are separate professional work.

A successful test does not give an unearthed socket an earth connection. A switched-off device also does not prove every part behind a cover is dead. When electrical work is planned, supplies from solar panels, batteries or other sources may need to be considered.

A plug-in socket tester is not a substitute for an installation assessment either. These devices have limitations; a favourable indication is not a complete safety result.

Frequently asked questions

Do I need tools to operate the test button? For normal accessible user controls, you need the device instructions and optionally a record of the result. You do not dismantle anything.

The test does not work during a power cut. Is the device faulty? Some tests need particular supply conditions. Follow the instructions and have uncertainty assessed.

Can I order a replacement RCD myself? The appropriate device depends on the installation. Have an electrician select, replace and verify it.

Ask CAS to investigate an unexpected result

Record the make, model and what happened during the test. Share those details with CAS Elektrotechniek while leaving the unit closed. Discuss a consumer-unit assessment. Call 112 for fire or immediate danger.

Sources

• Enexis: normal user operations
• Liander: checking an RCD
• Hager: user testing and intervals
• Electrical Safety First: socket-tester limitations