Insulation Monitoring System MEV

Insulation Monitoring System MEV

Insulation Level Monitoring - Electrical safety in the operating rooms

Insulation Monitoring System (MEV) monitors the safety of electrical equipment in operating rooms where defective electrical equipment can cause serious incidents. MEV –type insulation monitoring systems are required in the operating rooms in all countries in the European Union due to EU regulation.  (The word MEV comes from Finnish words, which means earth insulation level monitoring.)



PPO-Elektroniikka has delivered over 30,000 systems since 1983. The system is mandatory in all operating rooms in Finland. Nearly all operating rooms in Finland use our MEV-7 -system or its earlier generations. Our new fifth generation MEV-8 is now ready for the production.

MEV Insulation Monitoring System provides constant, safe, and secure monitoring of electrical systems in hospitals and other critical environments. MEV-units measure and control the power supply of IT systems. Units control either the insulation level of the IT system as well as the transformer load and temperature.


Our solution: MEV Insulation Monitoring System for hospitals
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.

The monitoring of the aforementioned operating conditions is very important as invisible parts of the defective electrical equipment can cause seriously dangerous situations. Examples of such places and processes in hospitals are operating rooms, operating-preparation and post-operation premises, anaesthetic rooms, intensive care rooms, heart catheterisation premises, arteriographic/ angiographic rooms and preterm-babies care rooms.

If the preliminary conditions for the malfunctioning of the system begin to form in the electricity supply of the devices used in the aforementioned critical environments, MEV immediately sets off an alarm, which prevents any accidents at a very early stage, thus saving money and even human lives.

Insulation Monitoring System is suitable also for other critical environments such as explosive sensitive EX-rooms, ammunition factories, chemical laboratories, production and service areas.

Reasons to use MEV - Insulation Monitoring System in critical environments
It is a matter of patient and personnel safety, and a matter of cost savings in hospitals. Regardless of all the precautionary measures, the possibility of device failure, power failure or human error cannot be discounted.

MEV -Insulation Monitoring System protects the patients and personnel from electric shocks as well as prevents electrical fires and burns.

MEV-System also ensures

  • supply of electrical power in all critical equipment
  • the operating room and equipment are efficiently deployed all the time
  • unnecessary downtime can be avoided
  • the personnel work more productively
  • the service life of surgical equipment is extended.

Although the European standard requires an IT system and insulation monitoring system, not all countries yet follow the legislation. In addition to that, law enforcement is currently inadequate.

Long before an electric fault occurs, MEV notifies the personnel to preventively correct possible future insulation faults, such as malfunction of PE-wires and isolation transformers. Thus, insulation faults can be corrected well before they lead to a power failure because the personnel are alerted in due time before a critical incident occurs.

Due to the safety technology embedded in the MEV, complex and expensive equipment, as well as the people around it can be saved from harm and work more efficiently. In addition, the MEV allows the planning of fault repairs in advance to better suit maintenance purposes and clients’ needs.


MEV Insulation Monitoring System - absolute reliability

MEV–type insulation monitoring systems are required in operating rooms and similar Group 2 medical premises in all countries in the European Union due to the EU regulation.

Leakages of electrical currents occur in new and old electrical devices alike. During a surgery, such leakages in the operating and other equipment can be dangerous both for the patient and the personnel who performs the surgical procedures.

Our solution is to separate the equipment of the operating room from the main power system with an isolation transformer. MEV monitors the electrical devices connected after that transformer. Our systems, which are specially developed for use in healthcare facilities and operating rooms in hospitals, include high-reliability isolation transformers and are internationally approved by medical authorities.

The fifth-generation MEV-8 

We have developed our newest, fifth-generation MEV-8 in cooperation with hospital engineers. Our MEV-8 meets all the regulatory acts and technical standards internationally. MEV-8 is also suitable for critical environments in industrial field.

MEV-8 line isolation monitoring relay measures leakage current from floating isolated AC system to ground. MEV-8 also monitor measurement wires and transformer load / temperature. Alarms are indicated via LED lights and relay contacts. MEV- 8 operates 230Vac, 50/60Hz.


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
room’s PC programmes via the rs-485 bus.

Coming: CU-8 Communication unit

-  32 additional addresses/CU-8. Max. 4 pcs/MEV-8 system.

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.

More detailed information: Mr. Petri Pelkonen or Mr. Kimmo Konttinen, tel. +358 9 566 0920


MEV-team - strong experience in insulation monitoring
Our MEV-team has 39 years’ 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

The new IFHE Digest 2019 has been published by The International Federation of Hospital Engineering (IFHE). On page 19, the article by our Development Manager Petri Pelkonen and Managing Director Timo Ohtonen: Important information about operating rooms and their electrical safety.

We had also a presentation of our MEV-7 -Insulation Level Monitoring System In  IFHE Digest 2017.

IFHE Digest -publication offers views from hospital and healthcare sector written by engineers, architects and facility managers all over the world. 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 Elektroniikka

Kaarelantie 21, 00430 Helsinki

+3589 - 566 09 20

Our office is open on weekdays 8-16 (UTC+2)