Yes - under the 18th Edition Wiring Regulations (BS 7671:2018 + A2:2022), surge protection devices (SPDs) are mandatory in most new electrical installations. Unless a documented risk assessment proves otherwise, SPDs must be fitted to protect against transient overvoltages. For contractors, that means fitting surge protection is now the default, not the exception.
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Why the 18th Edition Made SPDs Mandatory
The 18th Edition recognised the growing risk of voltage surges in modern electrical systems. Sensitive kit - from EV chargers to servers - can be damaged in milliseconds. That’s why Section 443 sets out clear rules on when SPDs must be installed.
- To prevent injury or risk to life
- To protect essential public services
- To safeguard cultural heritage
- To stop costly disruption to commercial/industrial activity
- To protect sites with large numbers of people
👉 In practice, this means almost every commercial, industrial, and public building requires surge protection as standard.
Do I Need Surge Protection in Domestic Installs?
Domestic properties are treated slightly differently, but the default expectation is still to fit surge protection. The exemption is narrow and becoming less relevant as homes become more technology-heavy.
- Single dwellings: Exempt only if the value of the installation and equipment doesn’t justify SPD costs.
- Modern homes: With EV chargers, heat pumps, PV inverters and smart systems, most now justify SPDs.
- Inspection risk: No SPD will usually mean a fail on an EICR unless the exemption is properly documented.
Check our Surge Protection Devices for options suited to residential installs.
Where Is Surge Protection Required?
Placement is just as important as choosing the right SPD. The regulations set out clear rules on where protection must be installed.
- At the origin of the installation (consumer unit or main distribution board)
- On new circuits feeding sensitive equipment such as IT, HVAC, or medical systems
- Within 10 metres of sensitive loads – the “10m rule” in Section 534
- Inside sub-boards if supplementary protection is needed for localised equipment
👉 Browse our Three Phase Boards & Accessories pre-fitted with SPDs for fast compliance.
Types of Surge Protection in the 18th Edition
The regs divide SPDs into three types, each designed for different scenarios. Knowing the difference is essential to get installs right first time.
- Type 1 SPD: Handles direct lightning strikes at the origin of the installation.
- Type 2 SPD: The default choice for most distribution boards, protects against indirect lightning and switching surges.
- Type 3 SPD: Local point-of-use protection for sensitive devices, installed in addition to Type 1 or 2.
Our 3 Phase SPD Complete with MCB is a ready-to-fit Type 2 unit built to Amendment 2 standards.
FAQs
Here are quick answers to the most common questions contractors ask about surge protection under the 18th Edition.
Is SPD a legal requirement in the UK?
Yes. Since January 2019, BS 7671:2018 requires SPDs unless a formal risk assessment proves they aren’t needed.
Does no SPD fail an EICR?
Yes. If an installation should have SPDs under Section 443 and doesn’t, it will be flagged as non-compliant.
When did SPD become mandatory in the UK?
With the introduction of the 18th Edition in 2019, reinforced by Amendment 2 (2022).
Do I need SPD on a 3-phase board?
Yes. Unless you can prove exemption by risk assessment, every new 3-phase install requires surge protection at the origin.
What is the 10m rule for SPD?
Sensitive equipment more than 10 metres away from an upstream SPD may need its own supplementary protection.