What Is Creepage & Clearance — IEC 60335?
Creepage and clearance assessment is an examination in which it is checked that the distances measured along the surface and through the air between conductive parts meet the minimum values defined in IEC 60664-1.
Purpose of Creepage & Clearance — IEC 60335
The purpose is to verify that the insulation distances required by the working voltage, overvoltage category and pollution degree are provided.
Which Products Is Creepage & Clearance — IEC 60335 Applied To?
- Printed circuit boards
- Power supplies and transformers
- Switchgear and terminal blocks
- Elektrikli cihazlar
- Drives and inverters
In Which Sectors Is Creepage & Clearance — IEC 60335 Used?
Standards Related to Creepage & Clearance — IEC 60335
- IEC 60335Safety in home and similar electrical devices test
- IEC 62368Security in audio, video and information technology devices test
- IEC 61010Safety in measuring, control and laboratory devices test
Creepage & Clearance — IEC 60335 Conditions
- Working voltage
- Voltage between the points being assessed
- Overvoltage category
- I – IV; determined according to the supply point
- Pollution degree
- 1 – 4; determined according to the environment of use
- Material group
- I, II, IIIa, IIIb according to CTI value
Equipment for Creepage & Clearance — IEC 60335
- Calibrated distance-measurement instruments and microscope
- Sectioning rig (if required)
- CTI test data
- Measurement templates
Sample Requirements for Creepage & Clearance — IEC 60335
- Critical points must be identified from the circuit diagram
- Working voltages must be calculated
- The CTI value of the insulation material used must be known
- Pollution degree and overvoltage category must be defined
Duration of Creepage & Clearance — IEC 60335
It depends on the number of points; typically half to one business day.
Creepage & Clearance — IEC 60335 Procedure
- 1Critical insulation points are identified from the circuit diagram.
- 2The working voltage is calculated for each point.
- 3Overvoltage category and pollution degree are determined.
- 4Minimum creepage and clearance values are read from the standard.
- 5Actual distances are measured and compared.
Creepage & Clearance — IEC 60335 Acceptance Criteria
The acceptance criterion is the minimum distances given in IEC 60664-1 according to working voltage, category, pollution degree and material group.
Evaluation of Results
Insufficient distances require a change to board layout or the insulation barrier. If a coating is applied, the assessment rules change.
Creepage & Clearance — IEC 60335 Report
- Standard applied
- Assessed points and working voltages
- Category, pollution degree and material group
- Required and measured distances
- Compliance assessment
Accreditation
EUROLAB holds internationally recognised accreditation obtained from accreditation bodies party to the IAF and ILAC multilateral recognition arrangements, under ISO/IEC 17025 for laboratory testing, ISO/IEC 17020 for inspection and surveillance, and ISO/IEC 17021-1 and ISO/IEC 17065 for system and product certification. This chain ensures the reports and certificates issued are accepted worldwide.
Whether this test can be offered within accredited scope depends on your product and the standard applied; since accreditation is method-based, the scope is confirmed in writing at the quotation stage.
Scope and authorisationsRelated Regulations
- LVD 2014/35/EU
Electrical Safety — What Does This Testing Field Cover?
The section below describes the field that the Creepage & Clearance test belongs to; the conditions and acceptance criteria of this particular test are given in the sections above. The scope specific to your product is confirmed in writing at the quotation stage.
Electrical safety testing shows that a device poses no risk of electric shock, fire or injury to the user in normal use and under foreseeable fault conditions. This family is the test group most often requested when a product enters the market; almost every electrically operated product passes through this gate.
The logic of the field rests on a single assumption: FAULTS WILL HAPPEN. Insulation will age, a component will short, a cable will break, the user will misuse the device. Standards therefore test not only normal operation but also single fault conditions. The sentence "the device works correctly" is not evidence in this field; the evidence is that the device stays safe when it fails.
Assessment addresses three layers together. In the constructional layer, insulation distances (creepage and clearance), protective barriers, earthing continuity, enclosure strength and component selection are examined — this layer is largely a matter of inspection and measurement rather than testing. In the electrical layer, dielectric strength, leakage current, insulation resistance and behaviour under fault conditions are measured. In the thermal layer, temperature rise in normal and abnormal operation is monitored; an overheating component is both a fire risk and a risk of insulation breakdown.
Which standard applies is determined by WHAT THE PRODUCT IS, and that decision affects the entire outcome. Household appliances fall under the IEC 60335 series, information technology and audio/video products under IEC 62368-1, measurement and laboratory equipment under IEC 61010-1, and medical devices under IEC 60601-1. A report obtained under the wrong standard is not accepted in the file even if the measurements it contains are correct.
Component conformity is often overlooked in this field. The safety of the device rests on the conformity of the transformer, optocoupler, fuse, switch and power supply it uses. The list of critical components and the certification status of each is part of the technical file; a change of component reopens the safety assessment.
Method groups in this field
Constructional examination
Insulation distances, barriers, earthing arrangement, accessibility and selection of critical components are examined. It comes before testing and many non-conformities are caught here.
Dielectric strength
It is verified that the insulation withstands the defined voltage. It must not be confused with the routine test on the production line; the type test is more severe.
Leakage current and earthing
The current that could reach the user is measured; the continuity and resistance of the protective earthing path are verified.
Heating tests
Temperatures of components, windings and accessible surfaces are measured in normal and abnormal operation.
Fault condition tests
Components are deliberately short-circuited or open-circuited; the appliance is expected not to cause a fire and not to make a hazardous part accessible.
Mechanical and enclosure tests
Impact, drop, strain relief, IP protection and the safety of moving parts are assessed.
Commonly confused in this field
- A CB certificate is not a CE declaration. CB is the output of a mutual recognition arrangement that eases national certification; the CE declaration is made by the manufacturer under its own responsibility.
- A part of IEC 60335 is not sufficient on its own; it is applied together with Part 1.
- IEC 60950-1 and IEC 60065 have been withdrawn. Old certificates based on these codes cannot be used in a current file.
- Separate certification of the adapter does not cover the conformity of the device; the device is assessed as the system it forms together with its power supply.
- A change of critical component (transformer, fuse, optocoupler supplier) is not a silent change; it requires the safety file to be reviewed.
Which decisions these results support
- CE declaration under the Low Voltage Directive
- IECEE CB certificate and entry into national certification schemes
- Assessing the safety impact of design changes
- Establishing and maintaining the critical component list
- Responding to market surveillance requests
Related Tests
Frequently Asked Questions About Creepage & Clearance — IEC 60335
According to which standard is Creepage & Clearance made?
Creepage & Clearance is executed in scope IEC 60664-1, IEC 62368-1, IEC 61010-1, IEC 60335-1, IEC 60335, IEC 62368 and IEC 61010. The limit values and acceptance criteria to be applied are defined in the product standard; The version valid for your product is confirmed in writing at the offer stage.
Which products does Creepage & Clearance apply to?
Mainly applied to Printed circuit boards, Power supplies and transformers, Switchgear and terminal blocks, Elektrikli cihazlar and Drives and inverters. Whether your product is included in the scope is determined by examining its technical specifications and intended use.
Under what conditions is Creepage & Clearance done?
The determining parameters are: Working voltage — Voltage between the points being assessed, Overvoltage category — I – IV; determined according to the supply point and Pollution degree — 1 – 4; determined according to the environment of use. The full terms are in the "Test Conditions" section on the page and vary depending on the product standard.
What kind of sample is needed for Creepage & Clearance?
Critical points must be identified from the circuit diagram, Working voltages must be calculated and The CTI value of the insulation material used must be known. The number of samples is determined according to the product standard and the scope to be reported.
How long does Creepage & Clearance take?
It depends on the number of points; typically half to one business day. This duration belongs to the experiment itself; sample preparation, queuing and reporting are also evaluated. A realistic schedule for your product is given in the offer.
What is the Creepage & Clearance result called "appropriate"?
The acceptance criterion is the minimum distances given in IEC 60664-1 according to working voltage, category, pollution degree and material group.