Surge protection is one of the most misunderstood parts of EV charger installation. Many installers know an SPD is usually expected, but there is still confusion around whether the charger needs its own protection, whether the main consumer unit is enough, and when a dedicated EV consumer unit with surge protection makes more sense.
Quick Answer: Yes - in almost all domestic and commercial installs, EV chargers need surge protection under BS 7671. In practice, that usually means fitting an SPD (surge protection device) either in the main consumer unit, at a board feeding the charger, or inside a dedicated EV consumer unit with surge protection. A charger’s internal electronics do not remove the need to consider proper supply-side SPD protection.
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. The key point is that the EV charger needs to be covered by effective surge protection, whether that is at the origin, on a board feeding the charger, or inside a dedicated EV unit.
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 or RCBO, and enclosure into one pre-assembled setup. They are ideal when the main consumer unit lacks space, or when the charger needs its own clearly separated protection. For many installers, this is the most straightforward way to create an EV consumer unit with surge protection.
Explore dedicated EV surge units here: EV Surge Protection Devices
Do EV Chargers Have Built-In Surge Protection?
Some EV chargers include internal protective features, but that does not automatically mean the installation has the right SPD arrangement for BS 7671 compliance.
What matters is whether the overall installation includes suitable supply-side surge protection for the charger and associated equipment.
- Some chargers include internal electronics protection
- Some rely on upstream circuit protection only
- Some installations still need a dedicated EV consumer unit with SPD
That is why installers should not assume that “built-in protection” removes the need for an SPD at the board or within a dedicated EV protection unit.
Practical point: If the charger spec is vague, or the main consumer unit has no spare way for an SPD, a dedicated EV consumer unit with surge protection is often the cleanest solution.
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
If you need a dedicated setup rather than relying on the main consumer unit, these are the types of products installers usually look for: EV surge protection devices, EV consumer units with surge protection, and pre-configured connection units with integrated SPD protection.
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 need surge protection?
In most installs, yes. Under BS 7671, surge protection is normally expected unless a justified decision is made not to provide it.
Do EV chargers have built-in surge protection?
Some chargers include internal protective features, but that does not automatically replace the need for proper installation-level SPD protection.
Do I need an SPD with my EV charger if the main consumer unit already has one?
Sometimes that is enough, but it depends on the layout of the installation, the length of the run, and where the charger is fed from. In other cases, local protection at the EV board is the cleaner option.
Should the SPD go in the main CU or in an EV unit?
Both can be valid. If the main consumer unit lacks space, or if the charger needs its own dedicated protection, an EV unit with built-in SPD is often the most practical solution.
Do three-phase EV chargers need a different SPD?
Yes. Three-phase EV chargers typically require a 4-pole Type 2 SPD matched to the installation.
👉 Protect EV chargers from damaging voltage spikes: Explore all EV Surge Protection Devices