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LECTURED BY:PN. NOR KHARUL AINA BINTI MAT DIN

IEC 60601

Introduced by the International Electrotechnical Commission to govern the design and development of medical equipment (mandatory)

Design / final test (type) standard

Standard is hazards specific

Requires two levels of protection be employed if one fails, the other protects

Insulation

Protective grounding or earthing

Protective impedance

Background on IEC60601

IEC60601 is an international electrical safety standard recognized in almost all developed countries as a complete set of regulations for the design of electrically safe medical equipment.

Prior to this standard, different countries had different standards, so manufacturers were forced to comply to many different standards.

Recently, the IEC601-1 standard has been adopted in most all developed countries, and may appear with different numbers such as UL2601, EN60601, or equivalent.

Purpose of Safety Testing

The basic purpose of safety testing medical electrical equipment is to be sure that a device is safe for the patient and the caregiver.

There are basically three stages of a product where safety testing is important: product development, production line, service department.

The IEC601-1 standard is mainly intended for product development, but can also be applied on the production line and eventually in the service area.

Terminology

Protective Earth is the ground conductor in the line cord or ground wire used for protectively grounding the piece of equipment.

Mains Voltage is the line or supply voltage. Usually 120VAC or 230VAC.

Single Fault Condition is where a single problem has occurred, such as an open ground wire.

Enclosure is the outer surface of the device.

Functional Earth is a ground on the DUT not intended for protective grounding purposes.

Applied Part is any part that intentionally comes in contact with the patient.

Accessible Part is a part of the equipment that can be touched without the use of a tool.

SIP/SOP is a signal input part/signal output part. Generally jacks on the exterior of the device.

Basic Areas of Safety Testing

1. Earth leakage current. This is essentially the current flowing down through the ground conductor in the line cord back to earth.

2. Enclosure leakage current. This is essentially the current that flows from any enclosure part if you were to touch it.

3. Applied part leakage. Commonly known as patient lead leakage. This is any leakage that flows from an applied part, between applied parts, or into an applied part.

4. Dielectric withstand. Commonly known as hipot testing. A high voltage is applied between insulated parts to be sure insulation will withstand the high voltage for a specified time.

5. Ground bond continuity. Commonly known as the high current ground continuity test. A current of 25 amps or more is run through the ground system to be sure the connections will handle it.

6. Residual voltage. Sometimes called the plug discharge test. This is the voltage present between any plug conductor 1 second after the plug is disconnected from power.

7. Accessible parts voltage. This is the voltage present on any accessible part, including those covered by service or access doors.

8. Retained energy. The energy that is stored in an accessible part.

9. Current draw. Current consumed by the product.

10. Power consumption. Power that is consumed by the product.

Single Faults & Normal Conditions

During the leakage tests, single faults and normal conditions are used to simulate all electrical possibilities that may occur in the field.

Single faults are essentially problem conditions that could occur. Since it is very unlikely that two faults would occur at one time, faults are tested one at a time.

Below is a list of the single faults used in IEC601-1

a. Open safety ground.
b. Open neutral.
c. Mains voltage on SIP/SOP.
d. Mains voltage on applied part.
e. Insulation shorting.
f. Open external power supply ground.
g. Open external power supply neutral.

Normal conditions are electrical conditions that normally occur on a daily basis and are not considered to be a problem. For example, grounding an patient applied part would not be a fault, since this happens anytime an ECG lead touches a metal bed frame.

Below are a list of the normal conditions used in IEC601-1.

a. Reversed AC line.
b. Functional earth grounded.
c. Patient lead grounded.
d. Isolated metal parts grounded.
e. Reversed mains voltage on SIP/SOP polarity.
f. Reversed mains voltage on applied part polarity.
g. External power supply functional earth grounded.

Medical Equipment (ME) definition

Treatment, monitoring or diagnoses of patient

Single main connection

Physical or electrical contact

Transfer energy to or from the patient or

Detect such energy transfer to or from the patient

ME Classification

Class I [ ] :- Equipment in which protection against electric shock does not rely solely on basic insulation but also provide by connecting all accessible conductive parts to the protective earth conductor of the mains wiring. So, these parts cannot become live in the case of failure of basic insulation.

Protective earth conductor is that conductor to be connected between the protective earth terminal and external protective earthing system. For flexible detachable supply cables, R