Residual Current Device Testing: Why does “Safety Switch” need regular testing?

Residual Current Devices or RCDs monitor the flow of current in electrical installation from the main power supply to the circuit. Upon detecting an imbalance current, the switches automatically cut off the current supply, thus preventing the sudden disposal of electricity that may cause electrical shock, serious injuries, or death in some cases. However, you have to conduct residual current device testing occasionally to make them keep working efficiently. That way, you can ensure that the RCD will respond in fatal situations. Read on to find out how you can conduct it successfully.

Residual Current Device Testing

Get Your Free Sample!

Enjoy a free sample worth UP TO $100!
Explore our custom services now. Email us at [email protected] for more details.

What is RCD Testing?

RCD testing is the process of inspecting the sensitivity of an RCD. In this test, you will check how quickly the under observation RCD trips and disconnect all the other electronic equipment of your circuit. The faster your RCDs trip, the greater is the protection they will provide against electrocution. RCD testing is also known as safety switch testing.

For successfully testing RCDs, you will underpass the device from these following two tests

  • Test 1: Pass the current that values half of the rated tripping current range between active and earth of the RCD for approximately 5 seconds. The RCD should pass this test and do not trip.
  • Test 2: Now, pass the current equal to the rated tripping current of RCD between active and earth. The RCDs trip within 40 milliseconds if it is a Type 1 RCD or 300 milliseconds if it is a Type 2 RCD. 

You can get the testing equipment from an electric wholesaler. Moreover, you need to consider the environment where you are conducting this test because external factors change the results.

Why Should You Test Residual Current Devices?

RCD testing is important due to the following reasons

  1. The electric appliances that you are going to connect to the circuit may have a little current leakage. As the RCD gets in direct contact with equipment, it may trip, and you never know you are relying on a disabled safety switch.
  2. Additionally, if you keep adding the devices in your electric network and the RCDs there keep tripping, the entire circuit will be overloaded.

Here in domestic installation, if you get these RCDs installed and checked with time, there may be 90% fewer fatalities. Therefore, you need to inspect these devices and maintain them properly. Hence, we recommend you get this done by a professional for better and more accurate results.

How Can You Test RCDs?

Here are some different methods of tests for which you can test your Residual Current Device

Push-Button Test

Push-button test ensures that the RCD, upon earth leakage, will trip. In addition, RCD will break the electric circuit so that the person in contact is safe from electric shock. Upon pressing the test button, the RCD will detect an imbalance in electricity, and the switch will be from on to off.

Ideally, you have to hire a competent person to perform the push button test. Furthermore, you can only conduct it if you have connected the circuit with the electricity supply.

Residual Current Device Testing– Operating Time Test

In the operating time test, the electrician measures the RCD’s actual trip time and check whether the time is less enough for normal operation in real-time.

Get Your Free Sample!

Enjoy a free sample worth UP TO $100!
Explore our custom services now. Email us at [email protected] for more details.

Residual Current Device Testing– Which electrical equipment can you use for testing?

For additional protection, you can test the RCD’s via

  • Built-in Buttons that you can use to ensure the RCD is available daily.
  •  Solenoid Voltmeter that provides an external path from live to earth. Also, it can test the wiring of RCD at the time of installation of the device.

The installers have to test the RCDs before installing. If they wire the device improperly, it will not work and may result in faulty appliances. 

Residual Current Device Testing

Residual Current Device Testing–When do RCDs need to be tested?

The frequency to test the RCD varies according to the external factors it is working on and the type of electrical appliances. The following table can help you to figure out what suits your device best.

Residual Current Device Testing

What to do during the Residual Current Devices Testing?

The electricians usually perform tests where the RCD is connected to a load circuit. Additionally, they need to test between the phase conductor and connected CPS. You require a device that works with less current, as you will get very little current flow, probably a few milli-amperes in this fault detection.

While you test the 3-Phase circuit of RCDs to protect a three-wire circuit, you have to connect your instrument’s neutral point to earth. Consequently, the test current will not increase the actual flow of electricity, and you will save yourself from getting the incorrect operating time of an RCD. In addition, you also have to remove all the safety devices when you are taking RCD for the test.

As a good practice, we advise you to first look into the correct operation present in the manual to know the threshold values. Secondly, you will reset the device before failing the test. In the end, you can use thermal scanners to check the overall issues. Now you are ready to create a comprehensive report on the problems you detected and a certificate to support the RCD’s current level of safety.

Simple Steps to Perform RCD Testing

You can perform these simple steps to make sure your RCD is live and running.

  1. Take a small lamp and plug it into a powerpoint. Check if it is working properly and leave the lamp turned on.
  2. Also, make sure the electricity is not dim, and you have the proper connection from the main supply.
  3. Turn off all the other electronic devices connected to the same electric circuit as a lamp. The lamp should be the only load here.
  4. Now push the testing button on all RCDs and check whether it turns off the switch or not. If the RCD does not operate, it means it is faulty. Do not keep holding your finger on the test button.
  5. If the RCD is turned off in the upper step, check whether the lamp is turned off or not. Also, test all the other lights and power points. You can check the points by plugging the small lamp on each of them and turn them on. If they light up the lamp, you should get an electrician to check your wiring comprehensively for any hidden fault.
  6. After completing the inspection, if RCD is doing completely fine, you can turn it back on. If not, get it changed by an electrician.


RCD testing is important as RCDs, if incomplete health, protect you from electric shocks or any power surges that can result in fatal damages. Regularly testing the device will make you find faults early and save you a lot of time and costs.

Here at Cloom, we recommend getting your RCD tested once every two or a maximum of three months. For that, we offer custom wiring assembly with attention to each detail so that your wiring is easy to check and maintain. Please fill out the form and contact our team now.

Get Your Free Sample!

Enjoy a free sample worth UP TO $100!
Explore our custom services now. Email us at [email protected] for more details.

Hey, I am John, General manager of Cloom and OurPCB.

I am a responsible, intelligent and experienced business professional with an extensive background in the electronics industry.

Reach me at [email protected] to get a quote for your projects.


Fill in your details and we’ll get back to you in 24 Hours.

contact us


Fill in your details and we’ll get back to you in 24 Hours.