EV Safety

BBT Area:

Target Course(s): TTJ

Project Outline

• The difference between an Electric Vehicle (EV) or a Hybrid Vehicle (HEV) is the drive train and power source.
• EV and HEV vehicles use the same brake, steering, suspension, lighting systems as an internal combustion engine (ICE) vehicle to operate.
• Outlined in this safety awareness lesson are the precautions and hazards related to working on an electric vehicle.

Related OVIN Sectors

• Connected & Autonomous Vehicles (C/AV)
• Auto & Parts Manufacturing
• Aftermarket, Maintenance & Repair

​

Prior Knowledge and Related Resources

• Students should understand and identify the differences between electric, hybrid and internal combustion engine driven vehicles
• Resources in this lesson will assist in identifying vehicles and safety precautions related to different repairs
• The safety precautions identified are related to regular maintenance and repair
• In a high school classroom, the high voltage systems should never be serviced or repaired without manufacturers’ specific training.

What is the main difference between an EV and a Hybrid?

​

• A Electric Vehicle (EV) is battery powered
• A Hybrid (HEV) has an internal combustion engine (ICE) and a battery.

What is an EV?

• The easiest way is by the model name or badging on the exterior of the vehicle (E or H suffix following standard model designation) and the presence of an exterior vehicle charging port

​

• Not all EVs and HEVs have identifying badging

How to tell if a vehicle is an EV or HEV

What is High Voltage?

• High voltage is any part of the vehicle system that is greater than 60 Volts

​

• Low voltage is any part of the vehicle system lower than 60 volts

​

• Most components of a vehicle are 12.6 Volts to 14.9 Volts and safe to repair

• Orange colored cables and wires identify the high voltage system (HV)
• Never perform any tasks where orange wires are indicated.
• Treat all parts as if they are HV parts until they are confirmed to be low voltage

​

​

Hazards while working on an EV

Safety Precautions working on an EV

• While working on electric vehicles, avoid contact with high-voltage cables.

​

• The only time when it is safe to work on the high voltage system is when the high-voltage battery has been completely disconnected.

​

• Always ensure that the right PPE is worn when working on EV vehicles.

​

Safety Precautions working on an EV

Safety Glasses

Safety glasses protect the wearer from hazards to the eyes and should be a standard part of every technician’s work uniform. It is always a good idea to confirm that the glasses comply with ANSI Z87+ standards: They must provide protection from impact and chemical exposure, and they must protect peripheral vision

Lineman Gloves

Commonly called hybrid or EV gloves, lineman gloves are designed to prevent the wearer from becoming part of an electrical circuit. You should wear them any time you are working with the high-voltage system, whether that is the battery or the energized components of the vehicle. Gloves must be certified every 6 months

Safety Precautions working on an EV

Inspect and Air Test Before Each Use

Physically inspect and air test the gloves using an air testing kit before each use. You’re looking to identify tears, holes, ozone cuts, defects, or material swelling or thinning. Perform air testing in compliance with the glove manufacturer’s recommendations and glove type requirements.

Wear with Leather Gloves

Never use lineman gloves without a pair of leather protector gloves over top. They are designed to protect the insulated gloves from wear and tear, such as cuts, abrasions, and punctures. There are limited exceptions to this requirement, but considering the high voltage of electric vehicle batteries, leather protectors are required.

​

• Hybrid (HEV) and Electric Vehicles (EVs) are automobiles which do not rely solely on an Internal Combustion Engine as the main power source for the vehicle
• Avoid all Orange Coloured Cables and wires as they are the main parts of the High Voltage System
• WEAR PERSONAL PROTECTIVE EQUIPMENT INCLUDING SAFETY GLASSES and use rubber gloves with no path through your heart when working on a Hybrid or EV
• Careless handling of components can cause serious injury or death
• Always ensure the system that is being worked on is low voltage

​

​

General Safety Rules

General Safety Rules

• Treat all High Voltage parts as if they have High Voltage until you have tested them with your Digital Volt Meter (DVOM) and are sure they are at zero or close to zero volts
• Remember the Internal Combustion Engine can start up at any time
• READY means the car is ON and it may move, engine on or not!
• Do not wear watches, jewelry or any metal
• If you have a pacemaker stay away from the drive motor magnets
• Always follow proper manufactures procedures for servicing components that are not connected to the High Voltage System

Battery Disconnect Procedures

​

• Disconnect 12 volt battery. (Same procedure as an ICE vehicle)
• Every EV and HEV has a master disconnect switch.
• The disconnect switch may be located in the cabin, truck or frunck.
• To locate and follow disconnect procedures, refer to manufacturers instructions as there is no standard location of the disconnect switch

​

General - Lifting an EV-HEV

• Due to their drivetrains and suspension, some HEVs and EVs may need the service or tow mode to be engaged to be able to roll the vehicle. This mode will also prevent damage to the air suspension components when lifted
• Some GM EV models, like the Hummer, will call it immobilization mode. Refer to the manufacturers guide prior to lifting
• Some EVs require specialized lifting pads to prevent battery damage

Lifting using a 2 post hoist

• You need to find the lift points to lift any vehicle. Most EVs and HEVs have specific lift points stamped into the unibody. Some EVs might require special blocks inserted into holes on the lift points. Some manufacturers recommend blocks or pucks that slide over the pinch welds on the rockers

​

Lifting with a 2 post hoist - Center of Gravity

• If you are using any type of two-post lift, you need to be aware of the center of gravity. EVs and HEVs can have a different center of gravity compared to a vehicle with an internal combustion engine
• Battery packs, inverters and motors can move the center of gravity to the rear
• The old rule that front-wheel-drive vehicles have the center of gravity at the side view mirrors and that a rear-wheel-drive vehicle’s center of gravity is below the driver’s seat does not apply for EVs and some HEVs
• Refer to the service information for where to spot the vehicle

​

​

Lifting with a 2 Post Hoist - Considerations

• Battery damage - Lifting in the wrong location or lifting a vehicle that is not allowed to be jacked up may cause serious damage to the battery pack itself.
• Weight - Vehicles with HV batteries may weigh more than those using standard combustion engines. Because of this extra weight from the battery, certain jacks, jack stands, and lifts may not be able to hold the vehicle safely, which in turn could cause injury to a technician as well as damage to the vehicle.

​

Lifting with a 2 Post Hoist - Considerations

• Damage to related components - Even if you are careful not to place the lift or jacks on the battery itself, there could be other HV components in the area that may get damaged during the lifting and supporting process. It is important to familiarize yourself with the location of HV components. Additional items like exhaust heat exchangers and associated cooling system lines and hoses also need to be protected from damage.
• Special tools and equipment - Some service information procedures require that lift hoist pads/adapters be properly placed in the designated areas to prevent damage while lifting the vehicle.

​

Lifting using a floor jack

• You need to find the lift points to lift any vehicle
• Most EVs and HEVs have specific lift points stamped into the unibody
• Some EVs might require special blocks inserted into holes on the lift points
• Some manufacturers recommend blocks or pucks that slide over the pinch welds on the rockers.

Drive on Automotive Lift

• When you first pull the car into the bay, the basic rules of spotting the vehicle remain the same. Always make sure the vehicle is straight and positioned in the centerline of the lift
• A roll-on or runway lift used for alignments or oil changes can be a safe bet for EVs and HEVs. But, these lifts can block access to some components under the vehicle
• If you use the rolling jacks, you need to use the correct adapters and lift points.

​

Drive on Automotive Lift

• The last part can be difficult for some HEVs and EVs due to their drivetrains. You might have to engage a service or tow mode to be able to roll the vehicle. On some models with air suspension, this mode will also prevent damage to the air suspension components when lifted
• Some GM EV and HEV models, like the Hummer, will call it immobilization mode
• Always place wheel chocks in front and behind the wheels to prevent the vehicle from rolling in service mode

​

Engine Service

• Most vehicles have an "idle stop" mode that shuts the gasoline engine off when the vehicle rolls to a stop - such as at a traffic light. The vehicle will then initially move under power from the electric motor when the accelerator is depressed, much like an electric golf cart. Shortly thereafter, the gasoline engine will restart and power the vehicle under normal driving conditions.

​

Engine Service

• A problem could occur in the shop if a hybrid vehicle is brought to a stop and the ignition key is left in the on position. A technician about to service the vehicle might think the engine is shut off and therefore safe to work on. Touching the accelerator may cause the motor to restart
• The key must be placed out of range of the vehicle and vehicle turned off
• Always follow manufacturers instructions and precautions
• After following manufacturers precautions, servicing an engine is identical to a non-electrical vehicle

Body Panel Repair Precautions

• The vehicle cannot be towed or moved on its road wheels to prevent possible HV system damage and to reduce the potential shock hazard.
• All HV system components must be initially located and inspected for signs of damage.
• All service requirements for the various systems must first be fully understood, for example the engine cooling system.
• Damaged body panel(s) must be checked behind for any HV system wires, connectors, modules or batteries that might have also sustained damage.

​

Body Panel Repair, Welding Precautions

• When welding on a HEV or EV, follow the same precautions with the 12-volt system as when welding on a conventional vehicle. In addition, there are precautions to take with the high-voltage battery.
• Disconnect both the 12-volt battery and the high-voltage battery service disconnect. (Note: always disable the high-voltage battery following the automaker’s repair information and follow all safety precautions.)
• Keep in mind that there is typically more than one method available for disabling the high-voltage system
• The preferred disabling method for technicians would be to remove the hybrid battery service disconnect

Required Tools and Materials

Engine service

• Certified Lineman's rubber gloves with no path through your heart (hand in pocket)
• 60 v at 1 amp is lethal

​

Required Tools and Materials

Engine service

• Leather over gloves to protect rubber gloves from being damaged

​

Required Tools and Materials

Engine service

EV and Hybrid lifting adapters must be used to prevent battery damage. Below is an example used by Tesla

Safety Concerns (including PPE if required)

• The high voltage battery may be damaged by lifting the vehicle incorrectly. Always follow manufacturers lifting instructions
• Always refer to manufacturers instructions whenever performing any task on a EV or HEV
• All orange wires are high voltage. Never perform any tasks on any component of the high voltage system
• HEVs engine may start at any time. Ensure the ignition is off and key is not within range to connect with the vehicle
• Always wear the appropriate PPE

​

Safety Quiz

1. What colour wires indicate high voltage? _________________
2. What is the maximum voltage is safe without special protection? _________________
3. Where should the ignition keys be when performing any work on an EV/HEV? _______________________________________________________________________________
4. How would you identify an EV or HEV in the shop? _______________________________________________________________________________
5. What 2 precautions should you take when lifting an EV or HEV? ______________________________________________________________________________
6. What PPE should be worn when working near high voltage wires or batteries? _______________________________________________________________________________
7. What does ICE ___________________________________________________________________
8. How should all electrical parts be treated on an EV or HEV until tested with a DVOM? _______________________________________________________________________________
9. Any non conductive gloves can be used while working on HEV and EVs. True False
10. There are no special precautions when an EV or HEV is placed on a drive on lift. True False

Safety Quiz Answers

1. What colour wires indicate high voltage? Orange
2. What is the maximum voltage is safe without special protection? 60 Volts
3. Where should the ignition keys be when performing any work on an EV/HEV? Outside of the communication range of the vehicle
4. How would you identify an EV or HEV in the shop? The model name or badging on the exterior of the vehicle (E or H suffix following standard model designation) and the presence of an exterior vehicle charging port
5. What 2 precautions should you take when lifting an EV or HEV? Caution must be taken to prevent battery damage using proper lift points and pads. The centre of gravity changes depending on battery placement.
6. What PPE should be worn when working near high voltage wires or batteries? Safety glasses, Safety boots, Certified Lineman's Gloves, Leather gloves
7. What does ICE Internal Combustion Engine
8. How should all electrical parts be treated on an EV or HEV until tested with a DVOM? Treat all parts as high voltage until tested.
9. Any non conductive gloves can be used while working on HEV and EVs. True False
10. There are no special precautions when an EV or HEV is placed on a drive on lift. True False

Outside Resources and References

• Tech Garage
• Garage Gurus
• OVIN
• Plug & Drive
• Underhood Service/EV Lifting
• Vehicle Service Pros
• Department of Energy