Working Safely on Electric and Hybrid Electric Vehicle Components

One of the most important skills you can develop is knowing how to work safely on electrical vehicle and hybrid electrical vehicle (EV/HEV) components. To do so, you must identify hazardous components and take precautions to avoid electrical shock. This lesson will help you review specific safe work practices for working on EV/HEVs and approach such work with a healthy respect.

Our primary concern is hazardous voltage. But what exactly is “hazardous”? Hazardous voltage is any voltage greater than 60 volts. Cables that handle the hazardous voltages will be orange. Orange cables are to be approached with extreme caution. There are some exceptions, such as mild hybrid vehicles using Belt Alternator Starter (BAS) systems. These hybrids use 42 volts and designate potentially hazardous voltage by use of blue cables. The same precautions should be taken with blue-colored cable systems as with orange-colored cable systems.

Figure 1. Orange cables in a lithium ion battery. 

Orange and blue color-coded cables are heavily insulated and generally not hazardous, but indicate connection to potentially fatal voltage sources. Care is to be taken when connections are uncovered. Watch the video below to learn about the hazards associated with uncovered connections and other areas hazards can be present.

To review, exercise extreme caution when approaching these high voltage components:

• EV/HEV battery packs contain high voltages with high current capacity.
• Large capacitors store high voltage and can discharge large amounts of amperage. Make sure they are discharged as specified by the vehicle manufacturer.
• Relays.