Electrical safety in hospitals: MEV®-8 Insulation Monitoring equipment for medical IT-systems

The MEV-8 Insulation Monitoring System monitors the safety of electrical equipment in operating rooms where defective electrical equipment can cause serious incidents. Our MEV -systems have saved lives and have protected valuable equipment in all Finnish hospitals for over 42 years.

We have developed our newest fifth-generation MEV-8 equipment in cooperation with hospital engineers and international partners. The new equipment meets all national and international (IEC 60364-7-710) regulations and technical standards.

The MEV-8 Insulation-level Monitoring System – How it works

  • The electric power network of the operating room is separated from the electrical grid by a medical insulation transformer.
  • The insulation-level monitoring system monitors all the electrical devices connected behind this transformer. Units control the insulation level of the IT system, the transformer load, temperature, and the continuity of protective earth 24/7.
  • The equipment indicates the faults and problems before dangerous situations arise.

Operating rooms are so-called group two medical facilities where the interfaces of electrically operated medical devices are used for near-heart functions. Faulty electrical equipment can be life-threatening for the patient and staff. Even the slightest equipment failure and leakage current can lead to burns, fire and even severe electric shock. Detecting electrical problems at an early stage is a crucial issue in the operating room.

MEV-8 PPT-presentation


The fifth-generation MEV-8

The MEV-8 insulation level monitoring system monitors all the electrical devices connected behind the medical transformer. Units control the insulation level of the IT system, the transformer load, temperature, and the continuity of protective earth 24/7.
Alarms are indicated via LED lights and relay contacts. MEV- 8 operates 230Vac, 50/60Hz.

The solution is also available as a pre-assembled IT power supply system, which is made to order according to the customer’s specifications. The equipment includes insulation level monitors, a protective isolation transformer and standard central accessories.


MEV-8 insulation level monitoring device

  • Monitors the insulation of a floating IT network (leakage current), transformer load (current A) and temperature (°C).

EV-8 Monitoring panel

  • Indicates insulation level alarms, line controller alarms and test lead faults.

M-8 Transformer monitoring panel

  • Indicates any overloading and temperature alarms.

SP-8 System monitoring panel

  • Indicates any insulation level alarms, line controller alarms, and test lead faults as well as transformer overloading and temperature alarms.

LC-8 Line controller

  • Monitors the continuity of a floating IT network’s protective earth.

FI-8 Fault locator unit

  • Locates any insulation faults in a floating IT network.

AG-8 Alarm transfer unit

  • AG-8 Alarm transfer unit transmits alarms to touch-screen panels and the control the room’s PC programmes via the rs-485 bus.

Maximising safety with a new-generation system

The starting point for the new-generation equipment was to transform the context of developing customer needs without compromising technical durability or operability. An essential feature for the international market was an insulation fault positioning feature, based on which we started to create the new insulation monitoring equipment.

Continuous PE-continuity monitoring 24/7

The new-generation equipment includes monitoring of PE continuity. This enables continuous 24/7 monitoring, prevents dangerous situations and decreases the costs of laborious inspections. It complements and ensures the continuity of protective earth between the distribution board and the last socket. If the PE wire breaks, the insulation-level monitoring will not work with that fuse wire.
A missing PE cable may also prevent automatic fuse operation.

Insulation monitoring brings safety, efficiency and cost-savings

  • Protects the patients and personnel from electric shocks
  • Prevents electrical fires and burns
  • Ensures that unnecessary downtime can be avoided
  • Ensures that the service life of surgical equipment is extended.

National legislation may not require IT-system and insulation-level monitoring in G2 facilities, but it is seriously worth considering. In addition to increasing safety, it also reduces costs. It is noteworthy that the proactive monitoring system eases technical work and ensures that operations are not interrupted. When problems are detected early, hazardous situations during operations can be prevented.

In Finland, every operating room is insulated with medical isolation transformers, and no surgery is performed without insulation-level monitoring.


Finnish hospitals have still older generations, such as MEV-4 -equipment in their operating rooms. That shows our MEV-system to be durable, reliable and long-lasting. Constant quality control and careful manufacturing guarantee the quality and functionality of our equipment.

We are looking for distributors, especially in Europe. We would be happy to tell you more.
We also deliver the MEV-8 system directly to hospitals all over the world.

Contact information

Managing Director Timo Ohtonen, +358 9 566 09210, timo.ohtonen@ppo-elektroniikka.fi

More detailed information about technics

Petri Pelkonen or Kimmo Konttinen, tel. +358 9 566 0920

MEV-team – strong experience in insulation monitoring

Our MEV-team has 40 years of experience in insulation monitoring. PPO-Elektroniikka Oy is a reliable partner. We have received the highest possible Dun & Bradstreet Credit Worthiness Classification and the highest credit rating by Bisnode Finland.

PPO-Elektroniikka Oy is a member of the Association of Finnish Hospital Engineering.

Articles in international publications


HEJ Healthcare Estate Journal 9/2020: Insulation monitoring brings safety and cost-savings Pages 69-72 / Authors Mr Timo Ohtonen and Mr Petri Pelkonen

The IFHE Digest. IFHE Digest -publication offers views from the hospital and healthcare sector written by engineers, architects and facility managers worldwide. IFHE Digest is published every year by The International Federation of Hospital Engineering.


We are happy to give more information about our MEV Insulation Monitoring System and electrical safety in medical G2 premises: +358 9 566 0920 or ppo@ppo-elektroniikka.fi.

MEV® is a registered trademark of PPO-Elektroniikka Oy.


MEV-8 Insulation Monitoring system (Fifth-generation, since 2019)

MEV-8 Brochure.pdf
MEV-8 Declaration of Conformity


Electrical Safety In Critical Environments

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