RCD (Residual Current Device) According to BS 7671
A Residual Current Device (RCD) is a safety device designed to quickly disconnect a circuit if it detects an imbalance in the electric current indicating a leakage of current to the ground. Here is detailed information on how RCDs work according to BS 7671:
RCDs monitor the flow of electric current in a circuit. If there is an imbalance between the live and neutral currents suggesting a leakage the RCD quickly disconnects the circuit to prevent the risk of electric shock or fire.
Types of RCDs:
- Fixed RCDs: Installed in the consumer unit (fuse box) and provide protection to a group of circuits or the entire installation.
- Socket-Outlet RCDs: Fitted into a socket outlet and protect the individual socket and any devices connected to it.
- Portable RCDs: Plug into a standard socket and provide temporary protection for devices connected to them.
BS 7671 recommends the use of RCDs with a sensitivity of 30mA for general-purpose protection. Higher sensitivity (e.g. 10mA) may be required in certain locations such as bathrooms and swimming pools.
BS 7671 mandates regular testing of RCDs to ensure proper functionality. This includes a trip-time test to verify that the RCD disconnects the circuit within the specified time limits.
Installation of RCDs should be carried out by a qualified electrician in accordance with BS 7671. The regulation specifies the types of circuits and locations where RCDs are required.
RCDs complement other protective devices such as circuit breakers and fuses. They provide additional protection against electric shock in scenarios where traditional protection may not be sufficient.
BS 7671 is periodically updated to incorporate technological advancements. It's essential to comply with the latest edition of the regulations to ensure the use of RCDs that meet current safety standards.
Implementing RCDs in electrical installations is a crucial safety measure and compliance with BS 7671 ensures that RCDs are installed and maintained according to recognized standards.
What zone does an emergency electrician call out cover?
Emergency electrician call-out zones can vary depending on the electrician or the electrical service company. Common coverage considerations include:
- Local Area: Many electricians serve a specific local area or community where they can quickly respond to emergencies.
- City or Urban Centers: Electricians based in cities may cover the entire city or specific boroughs within the city limits.
- Regional Coverage: Some service providers extend their coverage to broader regions, which can include numerous towns and even rural areas surrounding urban centers.
- National Networks: Larger companies may have a national network of electricians, allowing them to cover wider areas and dispatch local electricians from the nearest branch or partner company.
- Contractual Agreements: Certain electricians may have contractual agreements with commercial clients, such as chain stores or facilities, to provide services across multiple locations, regardless of normal geographical constraints.
- Special Circumstances: In some cases, especially in rural or remote locations, electricians might be willing to travel outside their usual service area to provide emergency assistance if there are no other services nearby.
When seeking an emergency electrician, it's important to verify that your location is within their service zone. Always ask about service area boundaries, especially if you're in a remote or newly developed area, to ensure you can receive prompt help when needed.