SEP G1 and F-gases: what these certificates mean in hybrid and EV service?

In EV/HEV, the problem is rarely a "lack of tools" — more often it's an incorrect procedure, misinterpretation of a measurement, or system contamination (e.g., A/C).

SEP G1 means the person is trained to work with electrical devices and safety principles. The F-gas certificate concerns the legal and correct handling of A/C systems (refrigerant, tightness, procedures).

For you as an owner, the most important thing is whether the service can show: a diagnostic process, a measurement result (e.g., HV insulation), and a clear conclusion — not just a "nice piece of paper."

SEP G1 covers devices up to 1 kV — and HV systems in electric vehicles operate in the range of 60–1000 V DC, meaning these qualifications are required for any interference with high-voltage circuits.

In the EV context, it means conscious work with the HV system, not improvisation. Insulated tools must meet the IEC 60900 standard (rated to 1000 V). The minimum insulation resistance required by ECE R100 is 100 Ω/V. HV systems with voltage >60 V DC require interlocking — breaking the circuit cuts off the power.

The F-gas certificate, regulated by EU Regulation 517/2014, is required for handling A/C systems with >3 kg of refrigerant or GWP >5. In practice, this means R134a (GWP = 1430) requires a certificate, while R1234yf (GWP = 4) formally may not require one, although service procedures remain analogous. Look not only for "SEP" itself but also for signs of mature work: disconnecting HV according to procedure, insulation measurement, checking harness condition, and documenting the result.

Don't just ask "do you have certificates?" Ask about what the procedure looks like and what measurement result you will receive.

A good service can explain: what they measure, what they measure with, what the result ranges are, and what that means for safety and costs.

Before commissioning a service, it's worth asking about certificates and the specific diagnostic process.

It's a simple way to reduce the risk of repairs done by trial and error.

If the car has had an accident, flooding, or an insulation fault — the first step should be verifying the safety of the HV system, and only then further work.