✍ In this Article: Why Standard Extension Leads Fall Short; What Makes an EV-Compatible Extension Lead; The Critical Need for RCD Protection; Practical Tips for Safe Use of EV Extension Leads
Portable chargers, commonly known as granny chargers, provide the most convenient way of topping up your EV when visiting family, staying with friends, on holiday, waiting for a dedicated home charger or even when you need to charge multiple vehicles at home. They are incredibly handy as they can plug right into a standard UK household socket.
Why Standard Extension Leads Fall Short ⚠️
Most extension leads found online and in local DIY stores often fall short in safety and functionality for EV charging. They lack the required cable specifications, weatherproofing, and built-in protection to handle the sustained high loads drawn by an electric vehicle draws over several hours.
Using an unsuitable extension lead can lead to overheating, plug / socket / cable damage, or in the worst case - a fire risk. This is why it's important to use an extension lead specifically designed for EV use, such as our 13A Weatherproof EV Extension Lead, which is built to perform safely under normal and demanding conditions alike.
What Makes an EV-Compatible 3-Pin Extension Lead
A proper EV extension lead is built with industrial-grade components to handle the demands of sustained high-current loads. Here's what sets them apart from standard alternatives:
- Heavy-duty cable: A minimum of 1.5 mm² H07RN-F rubber cable, designed to withstand mechanical stress, UV exposure, water, and chemicals. It handles continuous currents of 10A and peak currents up to 13A. The cable itself is rated for submersion up to a depth of 100 metres, though of course it should never be used in standing water intentionally.
- Wide temperature tolerance: Rated from −25°C to +60°C, making it well suited to the British climate year-round.
- Weatherproof rated: IP66 sockets that securely fit all 3-pin charger plugs, providing reliable protection for outdoor use.
- Residual Current Device (RCD) protection: Refer to the next section, below, for details.
Unlike typical "DIY" extension leads made with low-cost PVC, our specialised EV Extension Leads at Stella Charge® are built to this specification, giving you confidence when charging outdoors.
The Critical Need for RCD Protection
It is absolutely vital that 3-pin extension leads for portable electric vehicle charging are protected by a residual current device (RCD). An RCD is a life-saving safety device that instantly cuts the power if it detects a current leak - protecting you from potentially fatal electric shocks.
This matters with applications that require sustained high currents, such as EV charging, and in outdoor environments where the combination of electricity and external elements like weather can increase the risk of accidents. RCDs offer an invaluable level of personal protection that ordinary fuses and circuit breakers cannot match.
Our EVSE Extension Leads are designed with built-in inline RCDs integrated directly into the cable. Boasting a minimum IP66 rating, they maintain the water-resistant qualities of the extension cable, giving you peace of mind when charging your electric car (whether Type 1 or Type 2) outdoors.
Extend the cable, not the socket. For every Type 2 charger, portable or wall mounted.
Wherever you need extra reach, home or on-the-go, the same extension does the job. One cable that fits every Type 2 chargepoint, handles whatever speed your setup delivers (up to 22kW, 32A standard or three-phase supply) and stays useful even as your charging setup evolves.
EV Extension Cable 32A | Type 2 Charging Cable Find out more
Practical Tips for Safe Use
- Always ensure your extension lead is fully uncoiled before plugging in the portable 'granny' charger. A coiled cable can overheat under load.
- For safety, never connect multiple extension leads together ("daisy-chaining"); instead, use a single extension lead that is long enough for your setup.
- Limit the current to 10A or below for prolonged charging sessions. While the lead can handle up to 13A, sustained high current can cause the socket and/or connected charging infrastructure to overheat.
- Consider making it an annual routine to check your extension lead to ensure all connections are secure and the unit is in good condition.
- Always follow the manufacturer's guidelines for your specific portable charger. Not all chargers are designed to be used with extension leads, so do check compatibility before use.
Further guidance is provided in the User Guide supplied with your EV extension lead.
