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EV Safety Precautions for Collision Repair Facilities

When body shop technicians ask Dirk Fuchs about the risks involved while working on electric vehicles (EVs), I-CAR’s director of technical program and services says the danger is “very real.”

To help prepare and educate shops and their teams to repair EVs, Fuchs recently shared information about safety considerations during a webinar hosted by the Automotive Service Association (ASA), including how to assess the safety elements of a high-voltage vehicle the moment it arrives in a facility’s parking lot and key safety points in the repair process.

EV Safety: Where to Begin

Depending on the vehicle manufacturer, hybrid and battery EVs typically range from 200-920 volts. Fuchs talked about the risk of getting shocked with EVs due to the electrical power in the high-voltage system and the current, which runs the flow of electricity through a contactor.

“The current kills you, not the volt,” he explained. “Therefore, you need to know what kind of current there is.”

The following graph outlines the risk of current relative to the human body.

In the area AC1, no effects are felt, even if applied for long periods. A pain sensation begins with AC2; however, it is usually without a dangerous current running through the body.

Fuchs said the human body has a resistance of 1000 Ohm (the unit of electrical resistance).

“When a person encounters 400Volt in a high-voltage system, their body will be exposed to 400mA,” he explained. With this exposure, the body enters the dangerous area—AC3—which leads to muscle cramping.

“The danger, in this case, is that the body will not let go,” he said. “After 500ms, we enter the next area—AC4.” In this area, ventricular fibrillation, cardiac and respi-

ratory arrest can occur, which has deadly consequences.

Although EV technology can be very dangerous, Fuchs said that auto manufacturers have “many, many safety systems in place.” He stressed the importance of technicians being aware of the risks.

When an EV arrives at a collision repair facility via tow truck/ flatbed, Fuchs reminds technicians

to take precautions to stay safe. “You’re working on the unknown and that’s what can kill someone,” he said.

Fuchs recommended never double-clicking the start button of an EV. Instead, he advised pushing it one time without pressing the brake pedal. The light on the dashboard will come on, signifying you are in axillary mode and the battery contactors are open. Fuchs said no high voltage can go into the system using this method, which is important to know when connecting a diagnostic tool and pre-scanning the vehicle.

“Pre- and post-scanning EVs is really important to know the system configuration,” he said. “If there is a problem, we want it contained in the battery where the risk is.”

He also talked to shops about using a factory scanner to see the fault codes. By viewing the live data, technicians can check the battery/cell balancing.

“It’s important to know the difference between the minimum and maximum voltage between the individual battery cells,” he said.

The difference between two cells can lead to a higher internal resistance, which creates higher temperatures and can “end up in a fire.”

New OEM and aftermarket diagnostic tools are being introduced to the market to read the live data.

“It’s a great way to help the industry stay safe,” said Fuchs.

Before removing the battery, he encouraged technicians to always follow the described pre-scan procedure and check the battery temperature, as well as the live data and/or use a heat gun.

In a case where there is a problem with the battery, Fuchs highly recommended not bringing the vehicle into the shop until the vehicle can be monitored and the battery is removed.

Fuchs also advised shops to create a designated safe zone where EVs can be repaired apart from ICE vehicles in a very clean environment. “If someone grinds on a quarter panel or does a repair that is full

The EV Lab at I-CAR’s Chicago Technical Center in Vernon Hills, IL See EV Safety, Page 30

High-Voltage disconnecting procedure tips:

* Remove the ignition key and lock it in the lockbox so only the technician working on the vehicle has access� * When the ignition is off, disconnect the 12-volt battery (plus and minus cable) and then remove the high-voltage disconnect with proper personal protective equipment (PPE)� * Place the removed battery disconnect in the lockbox� * Ensure high voltage is isolated in the battery and perform a Zero [electrical] potential test after the vehicle manufacturer’s recommended wait time� The reason for the wait time is to let the capacitors completely drain because they can store energy like a battery and contain the same voltage, which is dangerous� * Use PPE to remove the connections closest to the high-voltage battery and use a two-pole voltmeter or multimeter to verify zero potential� * Always take the following three measures on both the battery and the system side to check if the high-voltage battery is isolated and the system is safe: high voltage plus against high voltage minus, high voltage plus against ground, and high voltage minus against ground�

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