Your Guide to IEC 60601-1

A review of the standard for medical electrical equipment and medical power supplies and how it has changed over the years.

What is IEC 60601-1?

IEC 60601-1 is the safety and performance standard set by the International Electrotechnical Commission (IEC) that medical electrical equipment must comply with before use. The IEC is a collaboration of experts from across the world that sets international standards for electrotechnology components, systems, and equipment that companies typically need to comply with in order to ensure their product is safe to use.

There are different versions of IEC 60601-1 across the USA, Canada and the EU, but they all contain very similar information about medical safety guidelines. The main purpose of IEC 60601-1 is to reduce risk when using the product as much as possible for both patient and operator, as well as making product design and use more user-friendly.

In terms of power supplies, they are considered a component that will be used in the final piece of medical electrical equipment. Since, the medical product will need to comply IEC 60601-1, the power supply will need to comply as well in order to remain compliant. IEC 60601-1 has been revised several times to keep it up to date with the latest developments with technology.

What is the timeline of IEC 60601?

1977 – Edition 1.0
The IEC first set up the standards for electrical medical equipment in 1977 with their publication of IEC 60601-1 (known as IEC 601 at the time). The primary goal of this standard was to create standards for medical electrical equipment for the general medical environment that is being used by qualified personnel. It provides guidelines for safe and reliable operation and has the ultimate goal of removing as much risk as possible during the use and operation of medical electrical equipment.

  • 1984: The first amendment to IEC 60601-1 was added in 1984. This amendment addressed requirements for medical electron accelerators.

1988 – Edition 2.0
The first full revision to IEC 60601-1 occurred in 1988. This revision focused on the safety in terms of vicinity to the patient.

  • 1991: First amendment to the 2nd edition included updates to address evolving technology of electromedical equipment.
  • 1995: Second amendment to the 2nd edition including general medical equipment updates. Corrigendum to the 2nd edition also added which is intended to help simplify interpretation and application of the General Standard.

2005 – Edition 3.0
The third revision to IEC 60601-1 happened in 2005. This edition focused more on risk management and adding means of patient protection (MOPP) and means of operator protection (MOOP). For certain equipment, requirements are supplemented or modified by special requirements of collateral or particular standard.

  • 2006, 2007, 2008, 2009: Updates to address basic safety and performance of medical electrical equipment.
  • 2012: Amendment 1 provides a tool to asses the significant changes between the third and second edition
  • 2013, 2014: Updates to address basic safety and performance of medical electrical equipment

What is specified in IEC 60601-1?

Overall, IEC 60601-1 specifies requirements for basic safety and essential performance of medical electrical equipment. It covers specifications on everything from insulation, leakage current, shock, creepage, and air clearances, to product layout, environment, and design. The standard is divided into two subsections containing collateral standards and particular standards

Collateral standards: Cover high level regulatory requirement that relates to safety of the most of the medical equipment that is tested to IEC 60601-1. These specify design standards for medical devices and are not necessarily pass/fail standards. There are 10 major collateral standards:

IEC 60601-1-x, where x equals the number of the collateral standard;

IEC 60601-1-1: Addresses medical electrical systems. First introduced in 1992 and revised in 1995 and 2000. It has since been withdrawn and is no longer a standalone document. The information in IEC 60601-1-1 has incorporated into the third edition of IEC 60601-1.

IEC 60601-1-2:2007: Introduced in 1993 to specify electromagnetic disturbances requirements and tests for electromagnetic compatibility (EMC) of medical equipment, medical electrical systems, information technology equipment for medical applications and any equipment used in medical electrical systems. Revised in 2001, 2004, 2010, 2014, and 2020. Equipment will not generate unwanted electromagnetic radiation and will not be unduly affected by it. Compliance with this standard ensures EMC Directive requirements are also met.

IEC 60601-1-3:2008: Radiation protection in diagnostic x-ray equipment; ensures stray radiation is minimized to protect both patient and operator

IEC 60601-1-4: Programmable Electrical Medical Systems (PEMS). Standard for software. This is no longer a standalone document and has been incorporated into third edition of IEC 60601-1.

IEC 60601-1-6:2007: Usability; Manufacturers must take requirements in this collateral standard into consideration during the design process to increase ergonomics. Equipment should be intuitive and easy to use to avoid user error.

IEC 60601-1-8: 2007: Medical alarms; guidance and management of alarm systems within medical equipment and what the user should do if they encounter one.

IEC 60601-1-9: 2008: Environmentally Conscious Design; air, water, biosphere, use of raw materials, and transport and packaging should all be considered during design of new products.

IEC 60601-1-10: 2008: Physiologic Closed Loop Controllers; design criteria that should be considered for medical devices that control the parameters that they are measuring so they are stable and reliable.

IEC 60601-1-11: 2010: Home healthcare equipment; addresses safety of home healthcare equipment being used by non-specialist users and possibility of poor wiring in building

Particular standards (IEC 60601-2-xx): provide additional information to collateral standards with about 80 particular standards that cover safety standards and performance for specific medical equipment such as cardiac defibrillators, infant incubators, electrocardiographs, medical beds, X-ray equipment:

The following cover the requirements for the basic safety and essential performance for certain medical equipment: IEC 60601-2-xx, where xx equals number of the particular standard.

Particular Standard

Classification

Particular Standard

Classification

Particular Standard

Classification
1 Electron accelerators 1MeV to 50MeV 23 Transcutaneous partial pressure monitoring equipment 46 Operating tables
2 High frequency surgical equipment and high frequency surgical accessories 24 Infusion pumps and controllers 47 Ambulatory electrocardiographic systems
3 Short-wave therapy equipment 25 Electrocardiographs 49 Multifunction patient monitoring equipment
4 Cardiac defibrillators 26 Electroencephalographs 50 Infant phototherapy equipment
5 Ultrasonic physiotherapy equipment 27 Electrocardiographic monitoring equipment 52 Medical Beds
6 Microwave therapy equipment 28 X-ray tube assemblies for medical diagnosis 54 X-ray equipment for radiography and radioscopy
8 Therapeutic X-ray equipment 10kV to 1MV range 29 Radiotherapy simulators 57 Non-laser light source equipment intended for therapeutic, diagnostic, monitoring, and cosmetic/aesthetic use
10 Nerve and muscle stimulators 31 Cardiac pacemakers with internal power source 62 High intensity therapeutic ultrasound (HITU) equipment
11 Gamma beam therapy equipment 33 Magnetic resonance equipment for medical diagnosis 63 Dental extra-oral X-ray equipment
12 Critical care ventilators 34 Invasive blood pressure monitoring equipment 64 Light ion beam medical electrical equipment
13 Anesthetic systems 36 Equipment for extracorporeally induced lithotripsy 65 Dental intra-oral X-ray equipment
16 Haemodialysis, haemodiafiltration, and haemofiltration equipment 37 Ultrasonic medical diagnostic and monitoring equipment 66 Hearing instruments and hearing instrument systems
17 Automatically controlled brachytherapy afterloading equipment 39 Peritoneal dialysis equipment 68 X-ray based image-guided radiotherapy equipment for use with electron accelerators, light ion beam therapy equipment and radionuclide beam therapy equipment
18 Endoscopic equipment 40 Electromyographs and evoked response equipment 75 Photodynamic therapy and photodynamic diagnosis equipment
19 Infant incubators 41 Surgical luminaires and luminaires for diagnosis 76 Low energy ionized gas hemostasis equipment
20 Infant transport incubators 43 X-ray equipment for interventional procedures 83 Home light therapy equipment
21 Infant radiant warmers 44 X-ray equipment for computed tomography 84 Emergency and transport ventilators
22 Surgical, cosmetic, therapeutic, and diagnostic laser equipment 45 Mammographic X-ray equipment and mammographic stereotactic devices

Means of Protection (MOP)
Means of protection (MOP) was added to IEC 60601-1 to address the risk of patients and equipment operators coming in contact with lethal mains voltage of medical devices. MOP can be achieved through protective earth connection (which protects against electrical shock), safety insulation, and minimum creepage and clearance distances. MOP can be classified as either 1 x MOP, which has basic insulation, or 2 x MOP, which has reinforced insulation.

One of the main specifications that means of protection addresses is creepage and clearance. Creepage and clearance in a supply offer space between conductive parts in a supply. Creepage measures this distance along the surface insulation, while clearance measures it through the air. It is important for medical equipment to have proper creepage to protect against deterioration caused by tracking, and proper clearance in order to prevent dielectric breakdown within the supply.

Minimum Creepage Distances and Air Clearances Between Parts of Opposite Polarity of the Mains Port

Working Voltage – Up to and Including

Working Voltage – Up to and Including Creepage Distance

Air Clearance

17VDC

12Vr.m.s. 0.8mm 0.4mm

43VDC

30Vr.m.s. 1mm

0.5mm

85VDC

60Vr.m.s. 1.3mm

0.7mm

177VDC

125Vr.m.s. 2mm

1mm

354VDC

250Vr.m.s. 3mm

1.6mm

566VDC

400Vr.m.s. 4mm

2.4mm

707VDC

500Vr.m.s. 5.5mm

3mm

934VDC

660Vr.m.s. 7mm

4mm

1061VDC

750Vr.m.s. 8mm

4.5mm

1414VDC 1000Vr.m.s. 11mm

6mm

The manufacturer of the medical product is the one that will determine the likelihood of their product to come in contact with patient and operator, and whether operator protection (MOOP) or patient protection (MOPP) is needed.

Means of Operator Protection (MOOP)
Means of operator protection is that standard of protection that provides safety measures for the operator of medical equipment. This means it will be necessary for equipment that will not be in contact with a patient. If used in a laboratory setting 2 x MOOP is sufficient to protect the operators of the equipment.

There are basic insulation standards (1xMOOP) and reinforced insulation standards (2xMOOP) that can be applied to medical equipment. Products will also need to have minimum air clearances from the mains part in order to comply with MOOP.

Isolation Creepage/Clearance Insulation
1 x MOOP 1500VAC 2.5mm/2mm Basic
2 x MOOP 3000VAC 5mm/4mm Double

 

Minimum Air Clearances Providing MOOP from the Mains Part

Working Voltage – Up to and Including Nominal Mains Voltage ≤150V (Mains transient Voltage 1500V) 150V < Nominal Mains Voltage ≤ 300V (Mains Transient Voltage 2500V) 300V < Nominal Mains Voltage ≤600V (Mains Transient Voltage 4000V)
Voltage Peak or DC Voltage r.m.s. (sinusoidal) Pollution Degrees 1 and 2 Pollution Degree 3 Pollution degrees 1, 2, and 3 Pollution degrees 1, 2, and 3
V V One MOOP Two MOOP One MOOP Two MOOP One MOOP Two MOOP One MOOP Two MOOP
210 150 1.0 2.0 1.3 2.6 2.0 4.0 3.2 6.4
450 300 1 MOOP 3.2, 2 MOOP 6.4 3.2 6.4
840 600 1 MOOP 3.2, 2 MOOP 6.4
1400 1000 1 MOOP 4.2, 2 MOOP 6.4
2800 2000 1 or 2 MOOP 8.4
7000 5000 1 or 2 MOOP 17.5
9800 7000 1 or 2 MOOP 25
14000 10000 1 or 2 MOOP 37
28000 20000 1 or 2 MOOP 80

* Air clearances for working voltages above 20kVr.m.s. or 28 KVDC can be prescribed by particular standards if necessary.

Note: Air clearances are a function of peak voltage in the circuit. The r.m.s. voltage column is provided for the special case where the voltage has a sinusoidal waveform.

Means of Patient Protection (MOPP)
Means of patient protection will be necessary for equipment that will come into contact with patients. It reduces the leakage currents and risk of electric shock if the patient may come in contact with conductive parts and AC currents. The most stringent requirements will be needed for electrocardiogram, applied parts, floating cardio, and type CF parts. The safest applied parts are F-type isolated applied parts in which patient connections are isolated from other parts of the equipment.

Like means of operator protection, means of patient protection has basic insulation standards (1xMOPP) and reinforced insulation standards (2xMOPP) to follow.

Isolation Creepage/Clearance Insulation
1 x MOPP 1500VAC 4mm/2.5mm Basic
2 x MOPP 4000VAC 8mm/5mm Double

 

Minimum Creepage Distances and Air Clearances Providing MOPP

Working Voltage – Up to and Including Working Voltage – Up to and Including Spacing Providing One MOPP Spacing Providing Two MOPP
Creepage Distance Air Clearance Creepage Distance Air Clearance
17VDC 12Vr.m.s. 1.7mm 0.8mm 3.4mm 1.6mm
43VDC 30Vr.m.s. 2mm 1mm 4mm 2mm
85VDC 60Vr.m.s. 2.3mm 1.2mm 4.6mm 2.4mm
177VDC 125Vr.m.s. 3mm 1.6mm 6mm 3.2mm
354VDC 250Vr.m.s. 4mm 2.5mm 8mm 5mm
566VDC 400Vr.m.s. 6mm 3.5mm 12mm 7mm
707VDC 500Vr.m.s. 8mm 4.5mm 16mm 9mm
934VDC 660Vr.m.s. 10.5mm 6mm 21mm 12mm
1061VDC 750Vr.m.s. 12mm 6.5mm 24mm 13mm
1414VDC 1000Vr.m.s. 16mm 9mm 32mm 18mm
1768VDC 1250 Vr.m.s. 20mm 11.4mm 40mm 22.8mm
2263VDC 1600 Vr.m.s. 25mm 14.3mm 50mm 28.6mm
2828VDC 2000 Vr.m.s. 32mm 18.3mm 64mm 36.6mm
3535VDC 2500 Vr.m.s. 40mm 22.9mm 80mm 45.8mm
4525VDC 3200 Vr.m.s. 50mm 28.6mm 100mm 57.2mm
5656VDC 4000 Vr.m.s. 63mm 36mm 126mm 72mm
7070VDC 5000 Vr.m.s. 80mm 45.7mm 160mm 91.4mm
8909VDC 6300 Vr.m.s. 100mm 57.1mm 200mm 114.mm
11312VDC 8000 Vr.m.s. 125mm 71.4mm 250mm 142.8mm
14140VDC 10000 Vr.m.s. 160mm 91.4mm 320mm 182.8mm

A product with 2 x MOPP will usually have the highest level of protection for a medical setting. It has the most stringent requirements of the MOP classifications including 4000VAC isolation, and creepage distance of 8mm.

Environmental Tests
Medical equipment needs to be tested to meet proper temperature, humidity, and atmospheric pressure conditions as indicated by IEC 60601-1.

Protection against Electrical Hazards
IEC 60601-1 outlines protections and limitations that medical equipment will need to have for electrical hazards like shock, water/particulate matter, and leakage current. It also outlines the standards required for methods of protecting against electrical hazards like protective earthing, MOOP, MOPP, leakage, insulation, creepage and air clearances, and layout.

Protection Against Mechanical Hazards
Medical equipment needs to have proper protection against certain mechanical hazards such as moving parts, expelled parts, instability, acoustic energy and vibration, and pneumatic and hydraulic pressure. IEC 60601-1 addresses the hazards that are associated with these moving parts and how the risk created from moving parts coming in contact with one another can be reduced.

Protection Against Unwanted/Excessive Radiation
Medical equipment is prone to exposure to unwanted or excessive radiation, given the environment it is used in. IEC 60601-1 outlines radiation limitations for x-radiation, alpha, beta, gamma and neutron particle radiation, microwave radiation, infrared radiation, and UV radiation.

Isolation
Isolation is the separation of incoming high voltage (mains) to the low voltage output. Isolation helps prevent voltages from passing between components and can help prevent electrical shock and breaks ground loops. According to IEC 60601-1, medical equipment needs to isolate its circuits form the supply mains on all poles simultaneously and have very low leakage current.

Leakage
Leakage current is the current that still flows input to output during supply operation. It is important for leakage current in medical power supply to be low because any additional current that reaches the patient or the caregiver that is not intended to could cause serious harm. Leakage requirements in a medical power supply are determined by IEC 60601-1.

Current Description Type B Applied Part Type BF Applied Part Type CF Applied Part
Normal Conditions Single Fault Conditions Normal Conditions Single Fault Conditions Normal Conditions Single Fault Conditions
Patient Auxiliary Current DC 10µA 50µA 10µA 50µA 10µA 50µA
AC 100µA 500µA 100µA 500µA 10µA 50µA
Patient Leakage Current From patient connection to earth DC 10µA 50µA 10µA 50µA 10µA 50µA
AC 100µA 500µA 100µA 500µA 10µA 50µA
Caused by an external voltage on SIP/SOP AC 10µA 50µA 10µA 50µA 10µA 50µA
DC 100µA 500µA 100µA 500µA 10µA 50µA
Total Patient Leakage Current* With same type of applied part connected together AC 50µA 100µA 50µA 100µA 50µA 100µA
DC 500µA 1000µA 500µA 1000µA 50µA 100µA
AC 50µA 100µA 50µA 100µA 50µA 100µA
DC 500µA 1000µA 500µA 1000µA 50µA 100µA

*These values are only applicable to equipment having multiple applied parts.

Note: Above chart is based on information from IEC 60601-1 Ver. 3 and may not necessarily be the most current information.

To help reduce leakage current, medical power supplies should be properly grounded, double insulated or reinforced for to meet the requirements of the standard.

Shock
Shock is a huge risk when it comes to medical supplies because shock an electric shock from a power supply could severely harm a patient or caregiver. Means of Operator Protection (MOOP) and Means of Patient Protection (MOPP) laid out in IEC 60601-1 outline how supplies can be designed and tested to reduce the risk of electric shock to both the operator and the patient. Both MOOP and MOPP have to meet specific dielectric strength, creepage/clearance, and protective earth connection requirements to be certified as IEC 60601-1 and appropriate for medical devices.

Properly isolating components like the AC input, DC output, and the supply itself can help reduce the risk of shock and damage to the supply. Isolation is especially important around conductors.

IEC 60601-1 Glossary of Terms

Term Description Symbol
EUT Equipment under testing; the equipment that is being tested

DUT

Device under testing; device that is being tested
Applied part Part of equipment that is designed to, or is likely to, come into physical contact with the patient

Patient Connection

Connections or metal parts intended to connect with the patient from applied part
Patient Environment Area in which patient can come to contact with medical equipment or contact between people touching the medical equipment and the patient can occur

F-Type Applied Part Applied part that is electrically isolated from earth and other parts of medical equipment. Floating F-type parts are either Type BF or Type CF applied parts

Type B Applied Part Applied part complying with specifications against electric shock; earth referenced; not suitable for direct cardiac application

Type BF Applied Part

F-Type applied part that complies with a higher degree of protection against shock than Type B; not suitable for direct cardiac application
Type CF Applied Part

F-Type applied part the complies with the highest degree of protection against electric shock than Type B

Medical electrical equipment

Equipment used for diagnosing or monitoring patients powered by one connection to main supply; contact with patient is not necessarily required
Medical Electrical system

Combination of equipment in which at least one is classified as medical electrical equipment and is connected by functional connection or use of multiple portable socket outlets

Class I

Protection against electrical shock by basic insulation through connecting exposed conductive parts to protective earth in fixed wiring of an installation.
Class II Protection against electrical shock by supplementary insulation (more than basic insulation). No provision for connection of exposed metalwork of equipment to protective conductor and no reliance on precautions taken in fixed wiring of installation. Class II is also known as ‘double insulated’

Creepage

Shortest distance between two conductive parts that is measured along the surface of insulation
Clearance Shortest distance between two conductive parts through the air

Ingress Protection (IP)

Protection against fluids and dust

 

The most up to date information on IEC 60601-1 can be found on the IEC website for download.

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