BS7671 18th edition Amendment 2 – now encompasses safety services

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Written by Mark Lloyd, Senior Product Manager- Power Supplies & Surge Protection

The current 18th edition version of BS7671, more commonly known as the wiring regs has been in force since January 2019, so a little over 3 years. I wrote a blog around the time predicting that the issue of surge protection would become much more of a hot topic and thankfully that has proved to be the case.

The list of instances where surge protection needs to be used was fairly clear and has resulted in surge protection being installed more routinely in domestic, commercial and industrial applications.

As a reminder the current 18th edition states: 

Protection against transient over-voltages shall be provided where the consequence caused by over voltage could:

i. Result in serious injury to, or loss of, human life
ii. Result in interruption of public services and/or damage cultural heritage
iii. Result in interruption of commercial or industrial activity
iv. Affect a large number of co-located individuals”

As always happens these standards don’t stand still for long and on the 28th of March of 2022, amendment 2 will come into effect. Depending on when this blog is published it may already be in effect.

Amendment 2 means the list of 4 scenarios are reduced to just 2, however they still capture all 4 “shall be’s” listed previously. Now Amendment 2 states:

“Protection against transient over-voltages shall be provided where the consequence caused by over voltage could result in:

i. Serious injury or loss of human life
ii. Significant financial or data loss”

Within the same section of the standard (443.4.1) are some notes, and the most significant in my opinion is note 3 which relates to safety systems. Note 3 essentially says that any consideration of surge protection should also include electrical safety systems associated with safety services. Part 2 of BS 7671 defines safety services as:

“An electrical system for electrical equipment provided to protect or warn persons in the event of a hazard, or essential to their evacuation from a location”

This means buildings or installations where there is a safety system installed such as, fire alarm systems, emergency lighting, CCTV, Public address and tannoy systems etc. would need to be protected from overvoltage. Such systems are common place in things like hotels, train stations, libraries, in fact nearly all public buildings.

The Phoenix Contact range of surge protection devices (SPDs) is almost uniquely placed to offer solutions to protect not only the power systems, but also the networking cables, loop devices as well as any telecom system that a security or fire alarm system uses.

For more information, contact Mark on 07717 335477 or email



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