High-voltage Safety
The increasing electrification and hybridisation of drive concepts is leading to greater use of high-voltage systems
in vehicles.
What does high voltage mean?
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Vehicles with high-voltage systems (HV) are fitted with components that work with voltages above 60V direct
voltage or 25V alternating voltage. Some of the components in these vehicles require a high level of electrical
power. The high-voltage systems in vehicles work with direct voltages of up to 650V and very high peak currents.
What dangers are involved in working with high-voltage
systems?
All movements in the human body are initiated by electrical control mechanisms. All muscle reactions, like your
heart beat or eyes winking, are controlled by electrical stimulation. These electrical stimulations are conducted
inside the body via nerve pathways in a similar way to currents in electrical circuits.
If you touch live high-voltage components, the current can flow through you body. Even with direct currents above
approximately 30mA, temporary heart pulse disturbance can occur depending on how long the current flows
through the body. At even higher currents in the body, serious internal burns occur and in some cases ventricular
fibrillation can result.
If the two poles of an electrical system are short-circuited, there is a risk of arcing. This can cause serious external
burns on the human body and electro-ophthalmia of the eyes.
Safety precautions
The risk of contact with live high-voltage components must be ruled out.
Only specially qualified personnel may perform work on the high-voltage system. In addition to the colour coding
and warnings given on labels on the components, there are technical safety measures.
The exact safety equipment used depends on the vehicle. In the following section, basic safety aspects are
explained without looking at the special installation situation in a vehicle.
Please refer to the workshop literature for which safety equipment is fitted in a specific vehicle.
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