High-voltage safety — how to safely work with electric and hybrid cars

Electric and hybrid cars are no longer a rarity on Danish roads, and for the breakdown technician it means that high-voltage systems are now a fixed part of everyday life. A damaged battery or damaged wiring can pose a real life threat, and therefore it is crucial to know the principles of safe behavior around these systems — even though it is not you who repairs them.

§How the infection control routine protects patients and staff

Electric cars and plug-in hybrids mark their high-voltage components with orange cables and warning signs with high-voltage symbols. The voltage in these systems typically ranges from several hundred volts — markedly above the 12-48 volts you find in a typical car's electrical system — and can give a life-threatening electric shock if the insulation is damaged. The battery pack usually sits low at the bottom of the car, often protected by a robust case, but a violent collision can damage both case and cells.

§Your role: recognize the danger do not touch the system

As a car mechanic it is not your job to open or repair a high-voltage system — this requires specific training in working with electric vehicles in line with industry organisation SKAD's guidelines for damaged electric and hybrid cars. Your task is to recognise signs of danger (visibly damaged orange cables, smell of burnt insulation, smoke, or a car that has been involved in a severe collision or fire), keep your distance and ensure that no one — not even the customer — touches damaged parts.

§The rescue sheet – your shortcut to important knowledge

Most car manufacturers issue a rescue sheet for each model — a diagram showing where the battery, high-voltage cables and any emergency shutoffs are located and where a rescue vehicle can safely cut if needed. The sheets are typically available in apps and databases that rescue services and recovery companies have access to. Being able to look up the rescue sheet for the current model before you touch the car is good practice and can determine whether a situation remains safe.

§Transport of electric and hybrid cars

An important practical rule is that most electric vehicles must not be towed with wheels on the road. If the drive wheels roll while the car is towed the electric motor can generate electricity which overloads the electronics and in worst case damages the battery pack. Therefore an electric car that cannot drive itself should as a starting point be transported on a flatbed truck with all four wheels off the road or lifted correctly according to the manufacturer's instructions. Always check the instruction manual or rescue card for the specific model as exceptions exist.

§When the battery is damaged: fire hazard and distance.

A physically damaged high-voltage battery can in rare cases develop a self-reinforcing heat development in the battery cells (thermal runaway) which can lead to fire — sometimes with a delay of hours after the actual incident. If an electric vehicle is involved in a major accident or fire, treat it with extra respect: keep distance, avoid placing it close to other vehicles or buildings during transport and storage, and follow emergency service instructions if they are present.

• 01Look for orange cables and warning signs — that's a sign of a high-voltage system.
• 02Never touch visibly damaged components or cables.
• 03Look up the rescue plan to find emergency stops and secure cutting points.
• 04Avoid towing on wheels—use a truck unless the manufacturer specifies otherwise.
• 05Be aware of delayed fire risk after damage to a high-voltage battery.

§Knowledge that grows with the car fleet

The share of electric and hybrid vehicles in the Danish car fleet grows year by year, and with it grows the need for auto helpers who know the special precautions. Many employers offer or require courses in handling electric vehicles as part of further training. Invest in that knowledge – it protects you, your colleagues, and the customers you help.