What you need to know about RCBOs in the workplace & Amendment 2
In the workplace keeping the power on is an important factor. Business services must not be interrupted by unwanted power outages. That’s why RCBOs should be used when there is also a requirement for 30mA protection for the users of the installation. Personal safety being paramount.
Protecting Users to Amendment 2 Requirements
Regulation 411.3.3 of the IET Wiring Regulations was revised by Amendment 2. This regulation now requires additional protection by means of a 30mA device for users of socket outlets (not rated higher than 32A) in all locations where they are liable to be used by persons of capability BA1, BA2 or BA3.
The terms BA1, BA2 or BA3 probably need some further explanation. Appendix 5 of the Wiring Regulations includes a list of external influences, and under the sub heading of ‘Utilization’ BA refers to the capability of persons. BA1 is described as an ordinary person (a person who is neither a skilled person nor an instructed person) BA2 as children, and BA3 as disabled.
No Exceptions Permitted
Therefore, in all locations where socket outlets (not rated higher than 32A) are liable to be used by ordinary persons, disabled persons, or children, additional protection by use of a 30mA device is mandatory. No exceptions permitted.
Providing Protection & Maintaining Power Continuity
Providing additional protection and maintaining power continuity is actually easy. Each socket circuit should be protected by an individual Type A 30mA RCBO. This will meet the requirements of Regulation 411.3.3 and the requirements of the business because it will eradicate unwanted tripping and guarantee that every healthy circuit remains in service.
Other Considerations Also Apply
Catering for modern demands on the electrical installation of a workplace, school or university environment for example means taking account of the connected equipment, and portable devices. These will have a significant impact upon the design of the installation and will no doubt bring DC influences and PE currents into consideration for the designer & installer.
Regulation 531.3.2 requires protective conductor currents (standing earth leakage not due to a fault) to be limited to 9mA for a 30mA device to help to avoid unwanted tripping but that can’t be achieved if several circuits are protected by one device.
Designers will not only have to take account of PE currents when dividing the installation into the necessary number of circuits. There are also the requirements of Chapter 31 & Regulations 314.1 to consider.
Regulation 314.1 requires the installation to be divided into the necessary number of circuits to
- avoid danger and minimize inconvenience in the event of a single fault
- take account of hazards that may arise from the failure of a single circuit
- reduce the possibility of unwanted tripping of RCDs
- facilitate safe inspection, testing and maintenance
Wherever additional protection by a 30mA device is required each circuit should be served by an individual Type A RCBO in order to meet the requirements of BS7671 including Amendment 2.
Discover more on Amendment 2
Learn more about RCBOs, Amendment 2 and what it means for your next installation here.