Towing Electric Vehicles Safely

Towing Electric Vehicles: A Comprehensive Guide for Safety

The automotive landscape is rapidly evolving, with electric vehicles (EVs) and hybrid vehicles (HEVs) becoming increasingly common. While these advancements offer environmental benefits and exciting new driving experiences, they also introduce unique challenges, particularly when it comes to vehicle recovery and towing. It's crucial for anyone involved in the motor vehicle repair, recovery, or towing industry to understand the specific risks associated with EVs and hybrid vehicles to ensure safety and prevent damage.

Understanding the Risks: High Voltage and More

Electric and hybrid vehicles operate with significantly higher voltages than traditional internal combustion engine vehicles. We're talking about direct current (DC) voltages that can reach up to 650 Volts, a stark contrast to the 12/24 Volts found in most cars. In dry conditions, accidental contact with live components at voltages exceeding 110 Volts DC can be fatal. For EVs and HEVs, DC voltages between 60 and 1500 Volts are classified as 'high voltage' (HV).

Beyond the immediate danger of electric shock, EV and hybrid battery systems contain chemicals that can be harmful if released. More importantly, these batteries store substantial amounts of energy. If mishandled, this stored energy can lead to explosions or fires. It's also vital to remember that some components can retain a dangerous voltage even when the vehicle is switched off.

The design of these electrified powertrains varies considerably between manufacturers. This means that generic advice is insufficient; obtaining and adhering to manufacturer-specific information is paramount for safe operations.

EVs and Hybrids: A Quick Overview

Electric Vehicles (EVs): These vehicles rely entirely on a large-capacity battery and electric motor(s) for propulsion. The battery is recharged from the electricity supply network, although some energy can be recaptured during braking (regenerative braking).

Hybrid Vehicles (HEVs): Hybrids typically combine an internal combustion engine (ICE) with an electric motor and battery. They can use both power sources independently or simultaneously. The ICE and regenerative braking help to charge the battery. Plug-in hybrids (PHEVs) offer the added convenience of charging their batteries directly from the mains electricity supply.

Specific Hazards in Detail

The presence of EVs and HEVs introduces several hazards beyond those typically encountered in the automotive sector:

• High Voltage Components: The risk of fatal electric shock from HV components and cabling is a primary concern.
• Stored Energy: Batteries store significant energy, posing risks of explosion or fire if not managed correctly.
• Residual Voltage: Components may remain live even when the vehicle is switched off.
• Unexpected Movement: Electric motors can cause unexpected vehicle movement due to magnetic forces.
• Manual Handling: Battery replacement, often involving heavy components, presents manual handling risks.
• Chemical and Gas Release: Damaged batteries can release explosive gases and harmful liquids.
• Silent Operation: The quiet nature of EVs can lead to unawareness of their movement.
• Medical Device Interference: Electrical systems may affect sensitive medical devices like pacemakers.

Safe Working Practices: Categorised Approach

To address these risks, a tiered approach to competency and control measures is necessary:

1. Valeting, Sales, and Low-Risk Activities

For personnel involved in these areas, awareness is key:

• Key Fob Management: Keep remote operation keys a safe distance from the vehicle to prevent accidental power-up and movement.
• Situational Awareness: Be aware that EVs are quiet and can move unexpectedly.
• Pressure Washing Caution: Avoid high-pressure washing of HV components and cabling (often coloured orange). Consult manufacturer guidelines before cleaning underbody areas or the engine bay.

2. Incident Response (Emergency Services & Recovery)

Safety is paramount during incident response:

• Visual Inspection: Check for any damage to HV components or cabling (usually orange). Assess the integrity of the battery pack.
• Isolation: If safe to do so, isolate the HV battery system using the vehicle's designated isolation device. Always follow manufacturer instructions.
• Towing Precautions:Avoid towing EVs and hybrids unless it is confirmed to be safe. Dangerous voltages can be generated by the movement of the drive wheels.
• Recovery onto Transport: Remove the remote key fob to a safe distance. Disconnect the standard 12/24V battery to prevent accidental activation.
• Information Sources: Utilise reliable manufacturer data or mobile data terminals for specific vehicle information.

3. Maintenance and Repair (Excluding HV Systems)

When working on non-HV aspects:

• Manufacturer Data: Always refer to vehicle-specific manufacturer and trade body information for necessary precautions.
• Key Management: Securely store remote operation keys away from the vehicle and control access.
• Pre-Work Checks: Visually inspect for damage to HV cabling (orange) or electrical components before commencing work.
• Isolation: Unless a task specifically requires the vehicle to be energised, isolate or disconnect the HV battery according to manufacturer instructions.
• Cable Awareness: Identify the location of HV cables before undertaking tasks like panel replacement, cutting, or welding. Take precautions to prevent damage.

4. Working on High Voltage Electrical Systems

This category demands the highest level of caution and expertise:

• In-Depth Manufacturer Guidance: Strictly adhere to manufacturer instructions for all procedures.
• Key Security: Keys must be kept securely away from the vehicle, with access strictly controlled.
• Damage Assessment: Thoroughly inspect for any damage to HV components or cabling.
• Isolation and Proving Dead: HV systems must be properly isolated (power disconnected and secured) and proven dead through testing before any work begins. Always lock off the power source and test to confirm all HV circuits are de-energised.
• Specialised Tools: Use only approved tools and test equipment, such as insulated tools compliant with GS38 standards.
• Stored Energy: Be aware that some electronic components can store dangerous levels of electricity even when the vehicle is off and the battery isolated. Consult manufacturer data for safe discharge procedures.
• Post-Collision Scenarios: If HV systems cannot be fully isolated or discharged (e.g., after a severe collision), follow manufacturer guidance for implementing control measures before further work.
• Thermal Considerations: Battery packs can be sensitive to high temperatures. Be mindful of operating conditions (e.g., paint booths) that might exceed maximum battery temperatures. Consider removing batteries or providing insulation.
• Working Live: This should only be considered as a last resort, and only if it is reasonable and safe. Appropriate PPE and stringent precautions, as per manufacturer guidance, are mandatory.
• Secured Work Area: Work on live equipment should be conducted in a secured area with clear warning signage to prevent unauthorised access.

Responding to EV Fires

EV fires present unique challenges:

• Vehicle Construction: Modern EVs often feature the battery pack as an integral structural component, typically forming the vehicle's entire underside (the "Universal Skateboard Design"). This battery structure is a watertight, fire-resistant enclosure designed to protect occupants and prevent external fires from reaching the cells.
• Identifying the Fire Source: If the fire does not involve the HV battery, it's a standard vehicle fire. However, if the HV battery is involved, the situation becomes significantly more complex.
• Thermal Runaway: Battery cells failing can trigger a chain reaction known as thermal runaway. This is an exothermic chemical reaction that doesn't require external oxygen. The only way to stop it is to cool the surrounding cells sufficiently to prevent them from failing.
• Firefighting Strategy: The primary challenge is cooling cells within a sealed, fire-resistant battery box. Excessive water usage (tens of thousands of gallons) may be required. In the absence of immediate exposure risks, allowing the battery to burn itself out (which can take about an hour) might be a more practical, albeit not ideal, solution than prolonged water application.
• Crucial Warning:Never pry, cut, or remove any part of the battery case to access a fire within it.

EV Extrication Considerations

Extrication from EVs requires careful planning:

• Stabilisation: The battery structure often forms the vehicle's rocker panels. If undamaged, these can be suitable for rescue struts or cribbing. However, never pierce, puncture, or create purchase points in the battery case for rescue struts, as this poses electrocution and fire risks.
• Lifting: EVs should ideally be lifted at the rocker panel. Be cautious with airbag lifts, ensuring they are placed over a large surface area.
• Fire Readiness: Maintain a charged hoseline with a firefighter in full PPE ready to combat a potential delayed fire during extrication.
• Hazardous Gases: Be aware of potential releases of harmful or flammable gases if the battery is smoking, popping, or sputtering. Don SCBA if irritation occurs.
• Cutting Precautions: Verify what you are cutting before making cuts. Do not cut any high-voltage cabling (typically bright orange). Manufacturers often route HV cables centrally, away from conventional cutting points.

Advice for Tow Operators

Tow operators play a critical role:

• Notification: Always inform the tow operator if a vehicle is electric or hybrid.
• Transport Method: All EVs and hybrids must be transported on a flatbed.
• Post-Incident Storage: If there is any damage or suspected damage, store the vehicle at least 50 feet away from any structure due to the risk of delayed fire.
• Dealer/Manufacturer Contact: Request that the tow operator contacts the vehicle's dealer or manufacturer for specific safety protocols.

Get Ready and Train

With the increasing prevalence of EVs, comprehensive training is essential for all personnel involved in vehicle recovery, repair, and roadside assistance. Understanding the unique characteristics and risks of these vehicles is not just recommended; it's a matter of safety.

For further information on qualifications and training, consider visiting the Institute of the Motor Industry (IMI).

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