High Voltage Guaranteed

Even for experienced workshop professionals, electric cars are often new territory. The right qualifications are required so that they can even touch them with their tools. DEKRA has set up various training courses.

The special qualification requires search and diagnosis of faults in the HV system. Photos: ProMotor/Volz

An electric car, too, is just a car. Like its conventional siblings, it needs maintenance and care, occasionally a repair. Changing the tyres? Painting the bonnet? Eliminate a rockfall in the windscreen? Replace the brake pads? Specialist companies don’t really need high-flyers for such jobs. However, electric cars and hybrids have electrotechnical components on board with voltages of more than 60 volts DC or 25 volts AC. These high-voltage systems (HV systems) are a source of danger for the naive screwdriver. If the mechanic drills an orange cable with the cordless screwdriver, an electric arc can occur which develops temperatures of over 1000 degrees Celsius. In this case, there is an acute danger to life. A workshop professional must therefore know exactly where the HV components and cables are located in the electric vehicle and how they are marked.

Instruction on the virtual school bench

For garages, body shops and paint shops, car glass manufacturers and tyre service providers, the direction should be clear. The companies must ensure that their personnel are suitably qualified to work on vehicles with high-voltage systems. The German Statutory Accident Insurance (DGUV) provides clear guidelines for this. For a trainee who is to operate the vehicle, replace the windscreen wipers and fill up with washing water, a simple briefing is sufficient. The qualification of the professionals as “electrotechnically instructed persons” (EuP) is much more demanding. The term means that the employee knows the sources of danger in the vehicle, the protective measures and behaviour. The instruction enables a mechanic to carry out all non-electrical work on the vehicle. This also includes work on the conventional vehicle electrical system. The high-voltage components and the orange cables remain outside. Here it says: Hands off.

The electrotechnical instruction is a prerequisite for standard jobs on the electric car. Photos: ProMotor/Volz

The expenditure for the electrotechnical instruction is manageable. It is enough for the employees to press the virtual school bench. DEKRA offers an online course with an examination on the Safety Web Portal, which can be completed in two hours. The workshops must document that the mechanics have actually completed the prescribed instruction. Under certain circumstances, however, instruction is only half the battle for a specialist company. After all, even with an electric car, sooner or later electrotechnical work on the high-voltage system is due. If, for example, a component, a new inverter, an air-conditioning compressor or even a complete rechargeable battery needs to be replaced, then a specialist is needed, or to be more precise: a specialist for high-voltage systems. Only this specialist can properly disconnect the HV system from the power supply before going to work.

DEKRA turns automotive professionals into experts for high-voltage systems

DEKRA has developed a seminar concept that enables seasoned motor vehicle professionals to receive safe and efficient further training to become experts in HV systems. The first step is a web-based training course. This course familiarizes graduates with the requirements and specifications for working with electric cars and hybrids. One focus of the self-study is on the basics of electrical engineering. At the end of the module, the know-how is tested in an online test. If you pass the exam, you have the ticket for the second part of the further training in your pocket. This includes a one-day attendance phase with two blocks of four teaching units each. The theoretical part includes the HV concept, vehicle technology and protective measures. The practical part deals, among other things, with how to disconnect an HV system from the power supply, how to prevent it from being switched on again and how to determine that it is disconnected from the power supply.

The expert for HV systems gets to work with suitable protective equipment. Photos: ProMotor/Volz

The search for and diagnosis of faults in the HV system is the supreme discipline

However, there are also certain limits for experts in HV systems in their daily work with electric cars. In the end, they must be able to find and diagnose faults in the high-voltage system and perform safety checks before putting the system back into operation. These skills make further qualifications necessary. DEKRA also offers suitable training for this. The main focus here is on practical tasks in handling a HV system. In the last stage they convey the special features which must be taken into account when working under voltage.