Applied Part: Type B, BF or CF
IEC 60601-1 uses the term applied part to refer to the part of the medical device which come into physical contact with
the patient in order for the device to carry out its intended function.
Applied parts are classified as Type B, Type BF or Type CF according to the nature of the device and the type of contact. Each classification has differing requirements from the point of view of protection against electrical shock.
Type CF is the most stringent classification, being required for those applications where the applied part is in direct conductive contact with the heart or other applications as considered necessary.
Type BF is less stringent than CF, and is generally for devices that have conductive contact with the patient, or having
medium or long term contact with the patient.
Type B is the least stringent classification, and is used for applied parts that are generally not conductive and can be
immediately released from the patient.
Type B applied parts may be connected to earth, while Type BF and CF are 'floating' and must be separated from earth.
Although IEC 60601-1 doesn't stipulate which classification is to be used for specific devices, the particular
standards, IEC 60601-2-XX, generally do specify which classification is required.
More details of electrical requirements for applied parts are provided by the articles on circuit separation and leakage currents.