Electric vehicles (EVs) have become an essential part of creating sustainable transportation solutions, but EV charging infrastructure doesn’t always fit perfectly into our daily lives. If you’ve found yourself with a charger that’s just out of reach, you’re not alone. The need to extend a charging cable’s reach is a common challenge for EV owners. However, it isn’t as straightforward as simply adding an extension cord—there are safety, regulatory, and efficiency factors to consider.
In this blog, we’ll explore three practical methods for extending your EV charger’s reach. We’ll also address key safety and power efficiency aspects, detailing the impact of cable length on charging performance. By the end, you’ll know exactly how to maximise charging convenience without compromising on safety or performance.
Can You Extend EV Charging Cables Safely?
The simple answer is yes, but EV chargers are quite different from regular electrical devices, and extending their reach can be a little tricky. Untangling the limits comes down to three variables:
- Safety regulations
- Power efficiency
- Compatibility
To ensure you’re making the right choice, we’ll walk you through each method and its implications for charging speed and power loss.
Method 1: Using Extension Cables
Many people first think of extension cables to bridge the gap between their EV and the charging point. While tempting, using an extension cable for EV chargers is generally discouraged – and often strictly regulated – due to safety risks.
Safety Factors
Most EV granny chargers carry high currents (particularly for Level 2 chargers). Standard extension cables aren’t designed to handle these loads, which can lead to overheating, fire risks, or even damage to your EV batteries. An appropriate extension cable must be heavy-duty, weatherproof, and specifically rated for high-power applications.
The UK guidelines, as per the Institution of Engineering and Technology (IET) Code of Practice, advise against using extension cables unless absolutely necessary. If you must, invest in a certified EV-specific extension cord, ensuring it meets IEC 61851 standards.
Impact on Power Loss and Charging
Extension cables introduce electrical resistance, which can lead to power losses. On average, for every additional 10 metres of cable, power losses can increase by approximately 2% to 3%.
For a 7kW home charger, this means you could lose 140 to 210 watts over a 10-metre cable extension. Not only does this waste energy, but it also increases charging times.
Optimal Max Length
Regulations and manufacturers typically recommend limiting cable extensions to a maximum of 20-25 metres. Beyond this, efficiency drops considerably, and risks escalate.
Pro Tip: If you must use an EV extension cable, double-check for overheating during charging and ensure connections are secure.
Method 2: Opting for Longer Charge Cables
The best workaround for limited range is to invest in a longer EV charge lead. These cables directly connect your car to the charger (as opposed to being an add-on), making them much safer and more efficient.
Available Lengths and Compatibility
Most EV manufacturers offer longer charging cables as aftermarket accessories. Standard cables are typically between 5 to 6 metres long, but extended versions can go up to 10 to 15 metres for added reach. These lengths are designed to handle high electrical loads, so they adhere to strict safety standards.
Power Loss and Charging Impact
Longer charge cables do experience resistance, but the impact is minimal compared to extension cables. Expect power losses of around 1% to 1.5% for every 10 metres.
Here’s how this translates to charging times for different speeds:
- 7kW Charger – A 10-metre increase in cable length will add about 5-10 minutes to a full charge.
- 22kW Charger – A 10-metre increase in cable length will add roughly 2-3 minutes to a full charge.
This is a negligible impact for most drivers and well worth the additional convenience.
Ideal Solutions for Most Use Cases
If you can’t reach your EV comfortably, opting for a longer charge cable should be your first choice. They’re safer, don’t compromise your charging speeds significantly, and adhere to compliance standards.
Method 3: Relocating Your Charger
If you frequently encounter charging reach issues, it may be worth considering a more permanent solution. By relocating your charging unit, you avoid the risks and inefficiencies of longer cables altogether.
Costs and Feasibility
Relocating a home EV charger typically costs anywhere from £300 to £600 in the UK, depending on the complexity of the work and the distance between the initial location and the new installation point.
Professionals will ensure the installation complies with safety standards, using appropriately rated components and ensuring minimal energy loss.
Ideal for Fixed Parking Locations
If your parking space is relatively fixed (e.g., your driveway), relocating your charger means you eliminate all future hassles. You’ll also boost the resale value of your home, as a well-placed EV charger is now a sought-after feature for buyers.
Pro Tip: Before making this investment, confirm whether your local grants (such as the OZEV EV Chargepoint Grant) may help reduce installation costs.
EV Charging Speed and Cable Length Limits
Understanding the impact of cable lengths on charging speeds is crucial to ensuring optimal performance. Here’s a summary of cable length limits based on charging speeds:
7kW Chargers (Level 2)
- Max Cable Length (for minimal power loss): 20-25 metres
- Power Loss per 10 metres of additional length: 2-3%
- Impact on Charging Time (approx.): Adds 5-10 minutes
22kW Chargers (Level 2 Fast Charger)
- Max Cable Length (for minimal power loss): 20 metres
- Power Loss per 10 metres of additional length: 1.5-2%
- Impact on Charging Time (approx.): Adds 2-3 minutes
DC Fast Chargers (50kW+)
Due to the high power loads, DC chargers are rarely extended. Manufacturers and service providers recommend parking configurations to eliminate the need for cable adjustments.
Key Takeaway: Longer lengths significantly impact 7kW chargers. For faster 22kW chargers, efficient cables (or relocating the charger) are ideal.
How to Decide on the Right Extension Method
Each method has its use case, and the best choice depends on your unique circumstances. Here’s a quick decision guide:
- Low Cost & Temporary = EV-specific extension cable (short-term only)
- Safe & Practical for Everyday Use = Invest in a longer charge cable
- Long-Term Fix = Relocate your charging unit
When choosing any method, always prioritise compliant products and professional installation.
Charge Smarter and Safer
Extending your EV charging reach can solve connectivity issues, but it’s essential to balance convenience with safety and efficiency. While EV-specific extension cables offer short-term fixes, longer charge cables and charger relocation are typically the smarter, safer choices for regular use.