Electrical safety in operating rooms

Electrical safety in operating rooms

The electrical safety of operating rooms is about protecting the patients and personnel from electric shocks.  Absolute reliability of electrical systems is of vital importance in medical environments.

Earth (grounding) leakages of electrical currents occur in new and old electrical devices alike. In the worst case, they can even cause the death of people around the defective equipment.

Insulation level monitoring warns of malfunctions

Electrical leakage currents occur in both old and new electrical devices due to malfunction, ageing and bad design. Common reasons for insulation faults include a bad connection, a damaged cable insulant and a defective component. Fast technological development and the rush to launch medical equipment create new kinds of challenges: new equipment may cause disturbances in the power network and other electrical devices.

All this requires insulation level monitoring, which is an invisible but important part of the routine of the operating room.  Insulation monitoring monitors the ungrounded system between an active phase conductor and earth. The system measures and controls the power supply of IT systems. The units control the insulation level of the IT system as well as the transformer load and temperature.

MEV-8 in the OR

Photo: HUS Helsinki Meilahti Tower Hospital

Standards regulating 

The European and national standards regulate electrical installations and the operation of devices in medical facilities. Operating rooms are classified as group II medical facilities. In Europe, these facilities require a specific IT system as well as monitoring equipment for the insulation space related to the IT system. European countries that have negotiated special circumstances concerning electrical installations in medical facilities are an exception to this.

Insulation monitoring system has been mandatory in all operating rooms in Finland since 1983. No operation will be performed in Finnish operating rooms if insulation monitoring is not in use.

PPO-Elektroniikka has been a forerunner in insulation monitoring. We developed the first-generation MEV system already in 1981.


  • SFS 6000-7-710 based on IEC 60364-7-710: 2012:
  • European Standard EN 55022, Class B
  • International Standard IEC 61557-8
  • IEC 61000-4-2/3/4/5/6