Safety

Traction packs carry enough energy to kill instantly, and unlike an ICE fault, an HV mistake usually gives you no second chance. Every procedure here exists because someone learned it the hard way.

De-Energizing Before Any HV Work

Before any high-voltage work, the system must be de-energized following the OE procedure — not a generic shortcut. The standard sequence is: pull the service disconnect (a loop or plug built into the pack circuit), wait the OE-specified interval — typically 5 to 15 minutes — for the capacitors in the inverter to bleed down, and then verify zero volts with a properly rated meter at the designated test points. All three steps matter. Pulling the disconnect alone proves nothing; the inverter capacitors can hold a lethal charge for minutes after disconnection.

Verification is done with a CAT III or CAT IV rated multimeter. And a zero reading is only trustworthy if the meter itself is trustworthy. Follow the safe-by-verification rule: prove the meter works on a known-live source first, then measure the target, and if you have any doubt about a zero-volt reading, wait another five minutes and retest with a known-good meter. Isolation is only ever proven by verified measurement — never by assumption, never by a warning label, never by how long the car has been sitting.

PPE and Cable Identification

The minimum glove protection for HV automotive work is Class 0 insulated rubber gloves, rated for 1000 volts, worn with leather protectors over them. The rubber provides the electrical insulation; the leather protects the rubber from cuts and punctures that would destroy that insulation. Gloves must be inspected before every use, air-tested (rolled and squeezed to check for pinhole leaks), and within their certification window — insulating gloves must be lab-retested every six months, and out-of-date gloves are not PPE, they are a liability.

High-voltage cabling is identified by orange sheathing — this is the universal industry standard across every manufacturer. Any orange-jacketed cable must be treated as live until the system has been de-energized and verified. Never touch, probe, or cut orange cable on an energized system. This matters most on collision and driveability jobs where a tech who does not normally do HV work encounters an orange harness routed through the repair area.

Crashed EVs and Battery Fires

A crashed EV is not a job for any tow driver — it requires trained first responders and trained handling throughout. The danger is that a physically damaged lithium pack can go into thermal runaway hours or even days after the crash, igniting spontaneously with no warning. That is why NFPA guidance calls for crashed EVs to be kept in an isolation or quarantine area, typically for 24 to 48 hours, away from buildings and other vehicles, with awareness training for everyone in the towing and storage chain.

If an HV battery does catch fire, understand what you are up against. Lithium battery fires are fought with large amounts of water — often applied for hours — with continued cooling afterward to prevent reignition. Foam alone, sand alone, or a handheld chemical extinguisher will not put out a pack fire. Specialized equipment such as fire blankets and vehicle immersion tanks may be needed, and even an apparently extinguished pack must be monitored because reignition risk persists long after the flames are out. Your role in the shop is to recognize the hazard, keep damaged-pack vehicles isolated, and call for the right response rather than improvising.