BS7671 18th Edition Requirements for Surge Protection Devices

Posted in Electrical | Electrical Testing, Safety & Compliance | Regulations & Practise
Published on April 4, 2019
3-phase SPDs by Hager

3-phase SPDs by Hager for BS7671 compliance

The 18th Edition of the BS7671 IET Wiring Regulations became the latest standard in electrical installations at the beginning of the year. The 18th Edition introduced several key amendments to the requirements for surge protection.

BS7671

BS7671 IET Wiring Regulations Ups 18th Edition

Chapter 53 (Protection, Isolation, Switching, Control & Monitoring) has been completely revised. Section 534 (Devices for Protection Against Overvoltage) focuses on the requirement for SPDs to protect against transient overvoltages.

This section focuses mainly on selection & erection requirements for SPDs protecting against transient overvoltages, as required by Section 443, the BS EN 62305 series, or as otherwise stated.

Given the small size of many of today’s sophisticated electronic components, protection from ever-smaller transient voltages is increasingly of paramount importance. Transients usually originate from lightning strikes, transformer switching, lighting and motors. SPDs therefore prevent equipment downtime, network failures and reduced lifespans for components.

Guidance is provided to help engineers choose the appropriate level of voltage protection. Crucially, emphasis has shifted from assessing whether you might need SPDs, to proving that you definitely don’t.

Surge Protection Devices are now mandatory

The bottom line is that any business that meets one of the following four criteria must no longer simply carry out a risk assessment. It’s now mandatory to install the appropriate surge protection on new installations.

BS7671 Section 433.3 now states: “Protection against transient over voltages shall be provided where the consequence caused by overvoltage effects results in:

  1. serious injury to, or loss of, human life
  2. interruption of public services and/or damage to cultural heritage
  3. interruption of commercial or industrial activity, or
  4. affects a large number of collocated individuals

In addition, any building fed via an overhead supply line will also require an SPD.

These criteria will apply across a very broad spectrum of businesses. Any business where a transient overvoltage could result in an interruption to commercial activity or public services must install surge protection.

Compliance & fixed wire inspections/testing

Finally, not all businesses will meet the above criteria. If not, a documented risk assessment is required as evidence if an SPD is not to be installed.

The latest regulations apply to all new installations. Regular fixed wire inspections & testing will be subject to, and assessed for, compliance with BS7671 IET 18th Edition.


Article by Barney Scott, Kiasu Group

© 2019 Barney Scott, Kiasu Group