Active medical devices – Q&A means of protection against electrical hazards/electrical shock

An infallible safety concept is the highest priority for the construction of medical electrical equipment. But what needs to be taken in account for the concept? And how are means of protection realized? In this article you will find the most important questions and answers on this topic.

The electrical safety concept for medical electrical equipment

The IEC 60601 standard family defines different means of protection (MOP) for the safety of medical electrical equipment.

Regardless of which means of protection is used: the focus is always to design the equipment single fault safe. So, if one of the means of protection would fails, the use of the equipment remains safe. This principle also applies for household, information technology and laboratory equipment.

Until the publication of the 3rd edition of the basic standard IEC 60601-1 in 2005, strict requirements had to be fulfilled for all parts of the medical electrical, regardless if the part or area of the device could be touched by the patient or not. 

By the publication of the 3rd edition of the standard, this approach was abandoned, and the requirements were split into two areas:

  • Means of patient protection (MOPP)
  • Means of operator protection (MOOP)

Why does such a split make sense?

The reasons why such a split between means of patient protection and means of operator protection makes sense are of varying nature. For example, it is considered that a patient suffers from a weak constitution or in the worst case is unconscious and therefore unable to respond to any kind of external interferences.

So, what is precisely associated with these means of protection against electrical hazards / electrical shock?

The standard differentiates between four different types of means of protection:

  1. Protective earthing of accessible metal parts
  2. Solid insulation
  3. Creepage distances and air clearances
  4. Protective impedance

The means of protection a) to d) are applicable for patient protection as well as operator protection. But they differ in their requirements and of course the limits for patient protection are stricter than for operator protection.

The safety concept will be visualized in a so-called “insulation diagram” which we would gladly assist you in drafting.

Would you like to find out more?

Do not hesitate to contact us for further information. We are looking forward to answering your individual questions or discuss your concerns.