The Electrical Safety Council announces results of its RCD investigation in domestic premises
An investigation into the reliability of RCDs commissioned by the Electrical Safety Council has found that in-service devices are reliable in long-term use, but has raised concerns that consumers are failing to follow manufacturers’ instructions to test the devices regularly. As a result, any faults that do develop are unlikely to be detected.
The long-term reliability of RCDs after prolonged inactivity had been brought into question by studies undertaken in other countries but until now there has been no published research carried out in the UK. In order to provide meaningful data for the UK and understand why RCDs might fail to operate, The Electrical Safety Council The Electrical Safety Council announces results of its RCD investigation in domestic premises
An investigation into the reliability of RCDs commissioned by the Electrical Safety Council has found that in-service devices are reliable in long-term use, but has raised concerns that consumers are failing to follow manufacturers’ instructions to test the devices regularly. As a result, any faults that do develop are unlikely to be detected.
The long-term reliability of RCDs after prolonged inactivity had been brought into question by studies undertaken in other countries but until now there has been no published research carried out in the UK. In order to provide meaningful data for the UK and understand why RCDs might fail to operate, The Electrical Safety Council commissioned ERA Technology to undertake a thorough investigation.
In total, 607 RCDs were tested by ERA in Housing Association and Local Housing Authority properties. Of those, over 96% were found to be fully functional and would have provided valuable protection from electric shock and fire caused by electrical fault.
The devices that failed to operate during testing did so due to a range of causes including deliberate shorting out, ingress of foreign materials, component misalignment and contact welding. These failures would have been picked up had the RCD integral test button been regularly operated by the householder. However, the overwhelming number of householders in the properties where testing took place admitted that they had never tested the device.
Phil Buckle, Director of Charitable Affairs at the Electrical Safety Council comments, “Whilst it’s reassuring to note that the failure rate of in-service RCDs was very low, it is clear that there is still a considerable education campaign to be done amongst householders as to the importance of testing their RCDs on a regular basis. Operating the test button would have picked up most, if not all, of the failed devices in our investigation. Those who have responsibility for the location of consumer units containing RCD devices should ensure that they are readily accessible in order to encourage use of the test button on a regular basis.” Current guidance is that the test button should be operated every three months.
Of the RCDs that failed, six had been deliberately shorted out to prevent ‘nuisance tripping’. Phil continues, “Shorting out RCDs is an extremely dangerous practice as it will not afford the householder any protection against electrocution or electrical fault related fires. Part of the Electrical Safety Council’s on-going work must be to encourage the owner or occupier of the property to seek the advice of a registered electrical contractor to investigate and deal with the underlying cause of the problem if nuisance tripping is occurring.”
Guidance is available to electrical contractors on this issue such as that found in the RCD Handbook produced by BEAMA Installation: Guide to the Selection and Application of Residual Current Devices.
The proposed requirements for electrical installations due to come into effect next year (BS7671:2008, 17th edition) place far greater reliance on RCD protection for safety. This is something which the Electrical Safety Council supports.
For further information contact media@electricalsafetyfirst.org.uk