Testing an RCD under NEN 3140

An RCD (residual current device) protects against dangerous leakage current. You test it with the test button, and a competent person also has it measured during an inspection. You press the test button yourself. A competent person does the measurement. You record the result in your own register and in the report of the NEN 3140 inspection. The RCD is part of the fixed installation, see also NEN 1010 versus NEN 3140. The general duty to work safely is set out in the Arbobesluit (Dutch Working Conditions Decree) .

Test the switch with the test button according to the manufacturer’s instructions, and record the test. If it does not trip, do not take the installation apart yourself. Report it to your installation responsible person immediately.

Two types of check

There are two checks that you should not confuse. You do the first one yourself. A competent person does the second one.

Check	Who	How often	What you record
Test button	Employee with instructions, or a VP (competent person)	According to your schedule and the manufacturer	Date, switch, result and name
Measurement of tripping time and leakage current	Competent person or inspector	At the inspection	The measured values in the report

You record the test button interval in your schedule, based on the manufacturer’s manual. If the manual does not state an interval, ask your installer or inspector which interval is suitable.

Example of a test record

This is a fictional example of a register for one distribution board.

Date	Switch	Group	Test button	Result	Initials
2 March 2026	RCD A1	Ground floor office	Tripped	OK	J.D.
1 June 2026	RCD A1	Ground floor office	Tripped	OK	J.D.
1 September 2026	RCD A2	Workshop	Did not trip	Fault reported	J.D.

The September row shows that you do not only test, but also respond to a fault. That is what an inspector wants to see.

What do you do if it does not trip?

Report it immediately to the installation responsible person, and note it in your register.
Do not keep switching the group on and off to try again.
Have a competent person look at it, and have them replace or repair the switch.

Never bypass the switch, and never replace it with a weaker or incorrect one. That is a dangerous mistake.

Common mistakes

Using the test button but not recording the result.
Testing only after a fault, and not according to the schedule.
Bypassing the switch or replacing it with an incorrect one.
Reporting a fault but then letting the group keep working without follow-up.
Not linking the test record to the installation, so it is unclear which switch it refers to.

Frequently asked questions

How often do I test the RCD?

According to your inspection schedule and the manufacturer’s instructions. Record the interval in your working procedure so that it can be checked.

May a tenant test the RCD?

Yes, if the instructions are available and your employer allows it. If the installation belongs to the landlord, report a fault to the landlord and to your own installation responsible person.

Is an RCD the same as a fuse?

No. A fuse protects against overload and short circuits. An RCD protects against leakage current, which is a different hazard.

What belongs in the inspection report?

The inspector’s measured values and a finding on whether the switch meets the requirements. See NEN 3140 inspection for what else the report contains.

Checklist for the test round

Is the test button accessible and undamaged?
Do you have the register at hand, so you can record the result straight away?
Do you know which groups are on which RCD?
Do you have the manufacturer’s instructions to hand?
Do you know who to call if the switch does not respond?

A test round that you skip has not been done, on paper. That also applies when the switch works fine.

Why testing and measuring are both needed

The test button checks whether the mechanism works. A measurement checks whether the switch trips within the required limits. A switch can respond well to the test button and still trip too slowly. That is why the inspector also takes a measurement, and you test the button in between.

Do I need to test each group separately?

Test per RCD. One RCD often protects several groups. The distribution board schedule shows which groups are on which RCD. That schedule should be up to date. See NEN 3140 inspection for the documentation requirements.

How long is a test result valid?

A test result is a snapshot. It says something about that day, not about the rest of the year. That is why you test according to the schedule, and not only when you think something is wrong.

Who is responsible if the switch does not work?

You, as the employer, are responsible for the safety of the installation. The installation responsible person decides on repairs. See Installation responsible person and work responsible person for the division of tasks.