What do the requirements mean in practice?

The requirements are meant to prevent dangerous contact voltages in facilities with earthing faults. To verify that an earthing facility meets the requirements, at least one of the points listed in formal requirements must be met. In high voltage facilities, contact voltage is calculated in relation to Table 4-2 in the guidelines to FEF:2008, 1 pole ground fault current and transition resistance. We at Trainor Kontroll og måling AS can help you measure and document this.

We measure and document

We calculate ground potential uplift in electro facilities based on switch-off times and earth currents. All calculations are made in accordance with requirements for documentation in regulations and standards. We carry out earthing plate measurements of transition resistance and main earthing connections in the facility are checked and measured. Such values can be organised in tables or lists, which then may be transferred to the business' QA system.

At Trainor, we focus on making documentation traceable, so that later checks can be compared with previous reference points and values. Traceable documentation gives increased quality and large cost savings for your company.

Formal requirements

  • Earthing systems are a part of an extended earthing network
  • Earthing potential lift in case of an earthing fault shall not exceed two times the permissible contact voltage.
  • Earthing potential lift in case of an earthing fault shall not exceed four times the permissible contact voltage at the same time that measures to reduce the contact voltage are implemented.
  • "Real contact voltage (UT) shall be less than the permissible contact voltage (UTP)"

(Guidelines for FEF:2006 § 4-11, Requirements for contact voltages)

Benjamin Abrahamsen

Benjamin Abrahamsen

Project Manager - Control and Measurement


+47 917 06 217

Ivar Andre Toms

Ivar Andrè Toms

Team Leader - Control and Measurement


+47 986 04 365

Vegard Sjoblom

Vegard Sjøblom

Project Engineer - Control and Measurement


+47 907 78 054