The two new definitions and one new regulation can be printed on less than half a page of A4 paper but in a new ten-page waste of paper document the IET have introduced the latest update to the 18th Edition Wiring Regulations; BS 7671:2018+A3:2024, released on July 31, 2024, and should be followed right away.
Older installations that followed previous versions of the standards might not meet all the new requirements. However, this doesn’t necessarily mean they are unsafe or need to be updated.
This simple update introduces two new definitions and one new regulation concerning the use of devices that control the flow of electricity in one or both directions.
The two new definitions introduced in Part 2 of BS 7671:2018+A3:2024 relate to bidirectional protective device and unidirectional protective devices.
Bidirectional Protective Devices: These are devices that can allow electrical current to flow in both directions. This is important in systems where energy can be both consumed and generated, such as in solar power systems with battery storage.
Unidirectional Protective Devices: These devices only allow electrical current to flow in one direction. They are typically used in systems where power needs to be directed in a specific path, like in traditional electrical circuits.
These new definitions help clarify how these types of devices should be used and understood in electrical installations.
The single new regulation 530.3.201 introduced in BS 7671:2018+A3:2024 specifically addresses the use of bidirectional and unidirectional protective devices in electrical installations.
Regulation 530.3.201 outlines the safety requirements, installation practices, and testing procedures for these devices to ensure they are used correctly. It is particularly relevant for systems that involve energy storage, renewable energy generation (like solar panels), and other advanced electrical systems where the direction of current flow is a critical factor.
This regulation ensures that these devices are installed in a way that maintains the safety and reliability of the entire electrical system, whether current flows in one direction or both.
Here is Amendment 3 without the filler in its entirety. Please feel free to print, cut out and insert it into your brown BS7671:2018+A2:2022 book.
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Part 2 Definitions
Bidirectional protective device. A protective device where it is intended by the manufacturer that a source of supply is connected to either or both sets of connection terminals.
Unidirectional protective device. A protective device where it is intended by the manufacturer that a source of supply is only connected to one defined set of connection terminals.
Regulation 530.3.201 Selection and erection of equipment for protection shall take account of appropriate use of either a unidirectional protective device or a bidirectional protective device.
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