Power surges and lightning strikes can destroy your EV charger instantly. In the UK, approximately 300,000 homes experience damaging power surges annually, and EV chargers are particularly vulnerable due to their constant grid connection.
This guide explains how to protect your investment and what to do if surge damage occurs.
Why EV Chargers Are Vulnerable
EV chargers face unique risks:
- Always connected - Unlike most appliances, chargers maintain grid connection 24/7
- Outdoor exposure - Many are wall-mounted outside, exposed to weather
- High-power circuits - 32A dedicated circuits carry more energy during surges
- Sensitive electronics - Smart chargers have delicate WiFi and control components
- Cable antenna effect - Long cables can pick up surge energy
UK Surge Statistics:
- 300,000+ surge events affect UK homes annually
- Lightning causes ~50,000 insurance claims per year
- Average EV charger replacement cost: £800-£1,500
- Average repair/replacement time: 2-6 weeks
Types of Power Surges
Lightning Strikes (Direct and Indirect)
Direct strikes are rare but catastrophic. They can:
- Destroy chargers, vehicles, and household electronics
- Cause fires
- Damage electrical infrastructure for the entire property
Indirect strikes are more common (within 1km of your home):
- Induce surges through power lines
- Enter through outdoor charger cables
- Damage sensitive electronics without obvious cause
UK Lightning Frequency:
- Southeast England: 10-15 lightning days/year
- Northwest England: 5-8 lightning days/year
- Scotland: 3-5 lightning days/year
- Summer months (June-August): Highest risk
Grid Switching Surges
More common than lightning:
- DNO switching operations
- Nearby industrial equipment starting/stopping
- Grid faults and repairs
- Transformer issues
Characteristics:
- Lower voltage than lightning (but still damaging)
- More frequent (multiple times per year in some areas)
- Often unnoticed until equipment fails
Internal Surges
Within your own home:
- Large appliances cycling (air conditioning, heat pumps)
- Motor-driven equipment starting
- DIY electrical work nearby
- Consumer unit switching
Surge Protection Options
Type 2 SPD at Consumer Unit (Essential)
What it is: A Surge Protection Device installed in your consumer unit that diverts surge energy to earth.
Cost: £100-£200 (supply and installation)
Protection Level: Protects entire home, including EV charger circuit
BS 7671 Requirement: Since January 2019, Type 2 SPDs are required for new installations where:
- Consequences of overvoltage are serious
- Structure is fed by overhead line
- Photovoltaic or wind power installed
For EV chargers: Most electricians now recommend SPD installation when adding an EV charger, even if not strictly required.
Installation:
- Must be installed by qualified electrician
- Requires spare way in consumer unit (or mini enclosure)
- Should be combined with RCD protection
- Green LED indicates operational status
Type 3 SPD at Charger (Additional Protection)
What it is: A secondary SPD installed directly before the EV charger, providing point-of-use protection.
Cost: £50-£80 (supply and installation)
Protection Level: Protects the charger circuit specifically, catching surges that pass the Type 2
Benefits:
- "Defence in depth" approach
- Protects against surges originating between consumer unit and charger
- Essential for long cable runs (>15m)
- Useful for outdoor/detached garage installations
Recommended Products:
- Hager SPK310 (~£45)
- Schneider iPRD (~£55)
- ABB OVR (~£50)
Built-in Charger Protection
Some EV chargers include surge protection:
| Charger | Built-in Protection | Rating |
|---|---|---|
| Zappi v2 | ✅ Type 3 SPD | Good |
| Wallbox Pulsar Plus | ⚠️ Basic MOV | Limited |
| Ohme Home Pro | ⚠️ Basic protection | Limited |
| Pod Point Solo 3 | ✅ SPD included | Good |
| Andersen A2 | ✅ Premium protection | Excellent |
Important: Built-in protection should complement, not replace, Type 2 SPD at consumer unit.
Installation Best Practices
Consumer Unit Surge Protection
Recommended Setup:
- Type 2 SPD installed at incoming supply (after main switch)
- 30mA RCD protecting EV charger circuit
- 32A RCBO or MCB for charger circuit
- Proper earthing - Essential for SPD function
Wiring Diagram:
Meter → Main Switch → Type 2 SPD → RCD → 32A MCB → EV Charger
SPD Coordination
For maximum protection:
- Type 2 at consumer unit (handles large surges)
- Type 3 near charger (catches residual surges)
- Minimum 10m cable between Type 2 and Type 3 (allows coordination)
Why coordination matters: If SPDs are too close, they don't share the surge energy properly. The let-through voltage to your charger may still be damaging.
Earthing Requirements
SPDs only work with proper earthing:
- TN-S or TN-C-S systems: SPDs connect to neutral and earth
- TT systems (common in rural areas): May need additional earth electrode
- Earth resistance: Must be below 200 ohms for effective protection
Your electrician will test: Earth fault loop impedance and continuity before installing SPDs.
Lightning-Specific Protection
During Thunderstorms
Immediate Actions:
- ✅ Unplug your car - Remove charging cable from vehicle
- ✅ Leave charger connected to mains - SPDs need power path to work
- ✅ Stay indoors - Don't touch charger during active storm
- ❌ Don't unplug charger from wall - This provides no benefit and puts you at risk
Why unplug the car?
The charging cable acts as an antenna. Unplugging from the car protects the vehicle's onboard charger and battery management system from surge damage.
After a Lightning Strike
If lightning strikes near your property:
- Wait 30 minutes after storm passes
- Check charger status lights/display
- Test with brief charging session
- Check your consumer unit - look for tripped breakers
- Inspect SPD status indicator (green = OK, red = replace)
Signs of Surge Damage:
- Charger won't power on
- Unusual error codes
- WiFi/app connectivity lost permanently
- Burning smell
- Visible damage to electronics
- RCD trips immediately when charging starts
What To Do After Surge Damage
Step 1: Safety First
- Don't touch damaged equipment
- Isolate the charger circuit (switch off MCB)
- Check for burning smells or visible damage
- Don't attempt repairs yourself
Step 2: Document Everything
For insurance claims:
- Photograph all damage
- Note date and time of incident
- Record weather conditions
- Keep damaged equipment (don't dispose)
- Get weather reports from Met Office
Step 3: Check Your Insurance
Home Insurance:
Most home insurance policies cover:
- Lightning damage (specifically listed peril)
- Power surge damage (usually under "accidental damage")
- Repair/replacement costs
Check your policy for:
- Deductible/excess amount (typically £100-£500)
- Coverage limits for electrical equipment
- Requirements for "like for like" replacement
- Any exclusions for outdoor equipment
Typical Claim Process:
- Call insurer within 48 hours
- Provide photos and incident details
- Get repair quote from qualified electrician
- Await insurer approval
- Proceed with repair/replacement
Step 4: Get Professional Assessment
Contact your installer or an electrician:
- Assess charger damage
- Check entire circuit for hidden damage
- Test consumer unit and SPDs
- Provide report for insurance
Cost: £80-£150 for inspection and report
Step 5: Repair or Replace
Repair Costs (if repairable):
| Damage | Typical Cost |
|---|---|
| Control board replacement | £150-£300 |
| Relay/contactor replacement | £100-£200 |
| Cable replacement | £50-£150 |
| Full charger replacement | £800-£1,500 |
| SPD replacement | £100-£200 |
Warranty Considerations:
Most charger warranties exclude surge and lightning damage. This is considered an external event, not a manufacturing defect. However:
- Wallbox: May offer goodwill replacement for premium customers
- Zappi: Extended warranty available including surge cover
- Pod Point: Check if business warranty includes additional cover
Cost-Benefit Analysis
Protection Investment vs Risk
Surge Protection Costs:
| Protection Level | One-Time Cost | Annual Cost |
|---|---|---|
| Type 2 SPD only | £100-£200 | £0 |
| Type 2 + Type 3 | £150-£280 | £0 |
| Premium (Type 1+2+3) | £400-£700 | £0 |
Potential Loss:
| Damage Scenario | Cost |
|---|---|
| Charger replacement | £800-£1,500 |
| Charger + vehicle OBC | £2,000-£5,000 |
| Charger + vehicle + home electronics | £5,000-£20,000 |
ROI Calculation:
- Annual surge probability (UK average): 0.3%
- Average unprotected damage: £1,500
- Expected annual loss: £4.50
- Type 2 SPD cost: £150
- Payback period: 33 years
However: Peace of mind, insurance premium reductions, and avoiding inconvenience make SPD installation worthwhile for most EV owners.
Maintenance and Testing
Annual SPD Check
DIY Visual Check (Monthly):
- Open consumer unit cover (if safe to do so)
- Check SPD status indicator:
- Green = operational
- Red = replace immediately
- Look for any visible damage or discolouration
Professional Check (Every 3-5 Years):
- Electrician tests SPD function
- Checks earth resistance
- Verifies coordination with other protection
- Cost: £50-£80 (often combined with EICR)
SPD Lifespan
SPDs degrade over time:
- Each surge event reduces capacity
- Typical lifespan: 10-20 years (without major strikes)
- After major surge: Immediate replacement needed
- Budget: £100-£200 every 15-20 years
Frequently Asked Questions
Do I need surge protection for my EV charger?
While not legally required in all cases, surge protection is strongly recommended for EV chargers. The 2019 BS 7671 amendment requires SPDs for many new installations. Given the £800-£1,500 charger replacement cost, the £100-£200 SPD investment is sensible protection.
Will surge protection stop all damage?
No protection is 100% effective against direct lightning strikes. However, Type 2 SPDs handle the vast majority of surge events (grid switching, indirect lightning). Combined Type 2+3 protection handles 99%+ of damaging surges.
Does my home insurance cover EV charger surge damage?
Most home insurance policies cover lightning and surge damage to electrical equipment. Check your policy wording—EV chargers should be covered as permanently installed equipment. Notify your insurer when you install a charger.
Should I unplug my charger during storms?
Unplug your car from the charger during active thunderstorms—the cable acts as an antenna. Leave the charger itself connected to the mains so any SPDs can function. Don't handle electrical equipment during storms.
How do I know if my SPD has been triggered?
Most SPDs have a status indicator window: green means operational, red means the SPD has absorbed a significant surge and needs replacement. Check monthly and always after storms.
Can I retrofit surge protection to my existing installation?
Yes. A qualified electrician can add Type 2 SPDs to most consumer units. Some units may need replacement if there's no spare way. Budget £100-£200 for Type 2 SPD retrofit. Always use a registered electrician (NICEIC, NAPIT, etc.).
