RCD Testing
Professional RCD Testing Across the UK
Verifying That Your Residual Current Devices Will Operate Correctly When It Matters
Electrical Testing UK carries out RCD testing for commercial, industrial and public sector clients. Residual current devices are a critical element of electrical safety. They detect earth faults and disconnect the supply within milliseconds. As a result, they protect people from electric shock and reduce the risk of electrical fire. However, an untested RCD cannot be relied upon to operate correctly under fault conditions. Pressing the test button only confirms the button works. It does not confirm the device will trip at the correct current and within the required time. Therefore our engineers test all types of RCD using calibrated instruments. In every case we record actual trip times and trip currents against the limits required by BS 7671.
Key Features Include
Calibrated Instrument Testing
We test all RCDs using calibrated instruments that measure actual trip times and trip currents, not the test button, which only confirms the mechanical function of the device.
All RCD Types Covered
We test all types and sensitivities of RCD including 30mA general purpose devices, 100mA and 300mA time-delayed devices, Type A, Type B and Type F devices, and RCBOs.
commercial and industrial Testing
We test RCDs in commercial distribution boards and industrial switchgear, with results documented and reported for every device tested.
Clear Pass or Fail Results
Every device tested receives a clear pass or fail result against the BS 7671 limits for trip time and trip current, with failed devices flagged for urgent replacement.
Replacement and Remedial Work
Where testing identifies failed or underperforming RCDs, Electrical Testing UK carries out replacement and remedial work directly, restoring protection without delay.
RCD Testing for Commercial, Industrial, and Public Sector Installations
Commercial Premises and Distribution Boards
Modern commercial distribution boards incorporate RCD or RCBO protection on every circuit. Over time, however, RCDs can degrade. Mechanical components wear, and electronic components drift from their original calibration. As a result, we test commercial RCDs using calibrated instruments. In every case we confirm each device trips within the time and current required by BS 7671. Larger installations also use a range of RCD types at different points. Often, time-delayed upstream devices coordinate with instantaneous downstream devices to provide discrimination. Therefore we verify trip times and trip currents for each device type, and we check that discrimination between upstream and downstream devices is maintained.
Industrial Switchgear and High-Risk Environments
Industrial installations may incorporate 100mA or 300mA time-delayed RCDs protecting distribution circuits. In addition, 30mA devices protect socket outlets and portable equipment. In high-risk environments, correct RCD operation is critical. These include construction sites, agricultural premises and other locations with an increased risk of electric shock. As a result, we test industrial RCDs carefully. Moreover, we verify that the protection provided suits the risk level of the environment.
Following Installation or Modification
New RCDs are sometimes installed, or an existing installation is modified in a way that affects the distribution system. In these cases, RCD testing confirms that all devices are correctly installed and correctly rated. It also confirms they operate within the required parameters. Therefore we test before the installation is put into service or returned to normal operation.
How We Test and What We Report
How RCDs Are Tested Using Calibrated Instruments
First, we test each RCD at the test currents required by BS 7671. For 30mA devices, this typically means half rated tripping current, rated tripping current and five times rated tripping current. At each test current we measure the actual trip time. Then we compare it against the maximum permitted trip time. For time-delayed devices, we also verify that the device does not trip instantaneously at the rated current. As a result, discrimination with downstream instantaneous devices is maintained. Finally, all tests use a calibrated RCD tester, and we record the results for every device.
What RCD Test Results Mean
A device that trips within the required time at the rated current passes. By contrast, a device that takes too long, or that fails to trip at all, fails. Therefore it must be replaced before the installation can be considered safe. A device that trips below the rated current may cause nuisance tripping, so it should also be investigated. In every case, we explain the result clearly and give an unambiguous pass or fail status for each device.
Reporting and Documentation
On completion, we provide a written test report. It records every RCD tested, the test currents applied, the measured trip times and the pass or fail status of each device. Failed devices are clearly identified with the recommended action. Finally, the report is provided in a format suitable for your compliance records and insurance requirements.
Why site operators and Businesses Choose Electrical Testing UK for RCD Testing
Calibrated instruments, not test buttons The test button on an RCD confirms the mechanical trip function works. It does not measure trip time or trip current and cannot confirm the device will operate correctly under real fault conditions. We use calibrated instruments that measure what actually matters.
Experience across all RCD types From standard 30mA commercial RCDs to Type B devices for EV chargers and industrial time-delayed devices, our engineers understand the different requirements and test parameters for all RCD types and apply the correct test procedure to each.
Testing and replacement under one contract Where testing identifies failed devices, we carry out replacement directly. One visit, one contractor, protection restored without the need to arrange a return visit or find a separate electrician.
Clear documentation for compliance purposes Our test reports provide the documented evidence of RCD performance that insurers, compliance auditors and, in the event of an incident, the courts require. Every device tested is recorded with its actual measured performance.
Qualified engineers, not subcontractors All RCD testing is carried out by our own NICEIC-qualified engineers. We do not subcontract, so quality and accountability remain with Electrical Testing UK throughout.
Our Work
RCD Testing
Electrical Testing UK tests residual current devices at commercial, industrial and public sector sites across the UK. Moreover, we provide calibrated instrument testing and clear documentation. As a result, site operators and businesses gain confidence that their RCD protection will operate correctly when it is needed.
National Coverage
We are a local Lincolnshire business, but with satellite offices in Peterborough, Cambridge, Nottingham and Enfield, no matter where you’re based in the UK, we can help. Just give us a call or drop us an email.
