Surge protection is one of the most misunderstood parts of EV charger installation. Since 18th Edition Amendment 2, many installers know SPDs are “usually required”, but the details - and where SPDs must be installed - still cause confusion.
Quick Answer: Yes - in almost all domestic and commercial installs, EV chargers require surge protection under BS 7671. The regulations assume an SPD should be fitted unless the client signs to decline protection. SPDs can be installed at the main consumer unit, at a submain feeding the charger, or inside a dedicated EV protection unit with integrated SPD.
See the full range here: EV Surge Protection Devices.
This guide breaks down exactly what the 18th Edition says, where SPDs must be installed, and which setups need local (charger-side) protection.
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What the 18th Edition Says About EV Surge Protection
BS 7671 (18th Edition Amendment 2) makes the requirement very clear: SPDs should be installed unless the client accepts the risk in writing.
For EV chargers, the risk is especially high because:
- The charger contains sensitive electronics
- It’s directly connected to incoming supplies
- Outdoor charging points are exposed to transient overvoltages
- Many chargers include communication modules/inverters
Because of this, EV installations are treated as high-risk environments - meaning SPDs are almost always required.
Where Should You Install SPDs for EV Chargers?
Under BS 7671, SPDs can be placed in one of three locations depending on the installation:
1. At the main consumer unit
This protects the whole installation, including the EV charger. A Type 2 SPD at the origin is the most common setup.
2. At the submain feeding the EV charger
If the charger is supplied via a garage board, outbuilding board or internal DB, SPD protection should also be installed locally on that submain.
3. Inside a dedicated EV protection unit
These units combine an SPD, MCB/RCBO and enclosure into one pre-assembled kit - ideal when the main consumer unit lacks space, or when the EV charger requires its own isolated protection.
Explore dedicated EV surge units here: EV Surge Protection Devices
EV Charger Protection Units With Integrated SPDs
Many installers now prefer using dedicated EV units with built-in surge protection. These provide:
- Pre-wired Type 2 SPD
- MCB or RCBO protection
- Metal enclosure (Amendment 3 compliant)
- Fast installation with fewer wiring errors
They are ideal when:
- The main CU has no spare ways
- The EV is fed from a garage/outbuilding
- Local discrimination is required
- You want protection immediately upstream of the charger
PME Supplies: SPD + Open-PEN Protection
Most UK homes use TNC-S (PME) earthing. EV chargers on PME require both:
- Surge protection
- Open-PEN protection (built into the charger or added upstream)
Surge protection deals with transient voltages. Open-PEN deals with dangerous broken-neutral scenarios.
For PME compliance without earth rods, you can pair SPD units with: PME Fault Detection Devices.
Recommended EV Surge Protection Units
Here are popular SPD units installers choose for EV chargers:
- 4-Way EV Protection Unit – 32A B Curve + SPD
- 4-Way EV Protection Unit – 32A C Curve + SPD
- EV Connection Unit – 100A Main Switch + SPD + 20A MCB
- EV Connection Unit – 100A Main Switch + SPD + 32A MCB
- IP65 8-Way EV Connection Unit – 32A + SPD
- IP65 EV Protection Unit – 40A B Curve + SPD
See all EV surge devices: EV Surge Protection Devices
FAQs
Some common installer questions about EV surge protection:
Do all EV chargers require SPDs?
Yes - unless the client signs to decline protection, SPDs are required under BS 7671.
Do chargers with built-in protection still need an SPD?
Yes. Charger-side protection does not replace supply-side surge protection.
Should the SPD go in the main CU or in an EV unit?
Both are acceptable. If the main CU lacks space, an EV connection unit with built-in SPD is ideal.
Do three-phase EV chargers need a different SPD?
Yes - they require a 4-pole Type 2 SPD for full three-phase protection.
👉 Protect EV chargers from damaging voltage spikes: Explore all EV Surge Protection Devices