The residual current device (RCD) is an essential electrical safety device which is installed to protect any person coming into contact with an installation from electric shock, and to mitigate the risk of electrical fires. An RCD breaker is installed into a circuit and has the function of continually monitoring current flow. The objective of the RCD is to detect any amount of current leakage in the circuit, which could be caused by a series of potential issues; faults, damage, water ingress or contact with live wires. If any amount of current leakage is detected, the RCD has the role of cutting off power supply to protect individuals from injury and the risk of an electrical fire.
So essentially the RCD has two main roles:
- To protect against electric shock
- To protect against electrical fire
The benefits of RCD protection
We have already established that the RCD has a major safety function, but what specific benefits does that bring?
- Compliance – By installing RCDs an employer has fulfilled their duty to protect employees and the general public, and a landlord has complied with their duty to protect commercial or domestic tenants and provide a safe and comfortable property.
- Peace of mind – An employer or tenant can be satisfied they have gone as far as is reasonably practicable in protecting employees and tenants.
- Additional protection – RCDs can be installed as an additional protection device in an electrical circuit.
- Simple installation – An RCD is typically located in a main distribution board or a consumer unit, and therefore it can protect multiple circuits running concurrently. There is no need for extensive or complex rewiring, and retrofitting an RCD doesn’t require an electrical system to be significantly modified or changed.
- Cost-effective – Installing RCD breakers in a system, such as an old fuse board for example, can be much cheaper than a complete rewire to upgrade the fuse board.
How RCDs are covered in the 18th Edition Wiring Regulations
As RCDs are such an effective safety device, it is no surprise that there are specific requirements for their use stipulated in the 18th Edition IET Wiring Regulations. These include:
- Any socket outlets which are rated up to 32A must have an RCD device installed, including domestic rooms such as kitchens, bathrooms and outdoor areas.
- All circuits supplying luminaires – a complete lighting system that includes a light source, a housing or body and any necessary electrical components – must be fitted with RCD protection.
- RCD protection must be used in all circuits which will supply portable equipment that is intended to be used outdoors.
- RCDs must be installed by a suitably qualified electrical installer and all installations must undergo a thorough testing regime.
The importance of RCDs
RCDs are an essential safety device which play a critical role in protecting individuals from injury and preventing electrical fires. They can detect the smallest amount of current leakage and immediately interrupt the power supply, hence minimising the risk of injury and building damage. This has the role of comprehensively improving the electrical safety of a building, be it commercial, industrial or residential.
These benefits are supplemented by an ease of installation and cost-effectiveness, which makes it one of the most commonly used safety components in an electrical installation. RCDs are reliable, robust and provide protection against electrical hazards, which complies with the requirements of the 18th Edition regulations.
Find out about an RCD tester on our knowledge base article also.
Please note that this section is for information purposes only. Anyone using equipment referred to in this section must be suitably qualified and/or experienced within the respective field. If in doubt before use, please consult a qualified electrician or engineer & thoroughly read all instruction booklets.
Please note that this section is for information purposes only. Anyone using equipment referred to in this section must be suitably qualified and/or experienced within the respective field. If in doubt before use, please consult a qualified electrician or engineer & thoroughly read all instruction booklets.