Standards are an integral part of product design and development, and are certainly important in medical applications. IEC 60601 is a series of technical standards applicable to Medical Electrical Equipment & Medical Electrical System for Basic Safety & Essential Performance. The basic scope of IEC 60601-1 is safety of patient, user and the equipment. 

IEC 60601-1 is the primary standard governing medical device design, Safety & essential Performance. So compliance with this standard has become a requirement for bringing new medical devices into the Market. Medical products must go through compliance testing and device approval before they can be marketed.

Freedom from unacceptable risk directly caused by physical hazards when ME equipment is used under normal condition and single fault condition.

Part of ME equipment that in normal use necessarily comes into physical contact with the patient for ME equipment or an ME system to perform its function.

Leakage current is the current that flows through the protective ground conductor to ground.

The collateral standards, often called horizontal standards, cover topics that may be applicable to all MEE based on the design of the equipment but are not covered by the general standard. Examples include electromagnetic disturbances (IEC 60601-1-2), usability (IEC 60601-1-6), and alarm systems (IEC 60601-1-8)

Particular standards (numbered 60601-2-X) define the requirements for specific products or specific measurements built into products, e.g. MR scanners (IEC 60601-2-33) or Electroencephalograms (IEC 60601-2-26). Collaterals and Particulars may have their own revisions which are different from the General Standard.

General requirements for basic safety and essential performance like IEC 60601-1.