Touch Current – IEC 60335 / IEC 62368 / IEC 61010

What Is Touch Current — IEC 60335?

The touch current test is a test in which the current passing from the device's accessible parts through a measurement network representing the electrical behaviour of the human body is measured. IEC 60990 defines different networks for perception, reaction and let-go thresholds.

Purpose of Touch Current — IEC 60335

The purpose is to verify that the current that would flow if the user touched the device stays below perceptible or hazardous thresholds.

Which Products Is Touch Current — IEC 60335 Applied To?

Information-technology equipment
Audio and video equipment
Household appliances
Medical devices
Power supplies

In Which Sectors Is Touch Current — IEC 60335 Used?

ElectricalElectronicsMachineryMedical Device

Standards Related to Touch Current — 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

Touch Current — IEC 60335 Conditions

Measurement network: Weighted networks defined in IEC 60990 (perception/reaction, let-go)
Supply voltage: Defined in the standard; a multiple of rated voltage
Conditions: Normal operation and single-fault conditions
Contact points: Accessible surfaces and terminals

Equipment for Touch Current — IEC 60335

IEC 60990 measurement network and meter
Isolation transformer
Programmable AC source
Contact electrodes

Sample Requirements for Touch Current — IEC 60335

Accessible surfaces must be determined
The device must be brought to steady-state temperature
Fault conditions must be planned
The insulation class must be documented

Duration of Touch Current — IEC 60335

Depends on the number of points and conditions; typically half a working day.

Touch Current — IEC 60335 Procedure

1The device is operated at rated conditions.
2The appropriate measurement network is selected and connected.
3Current is measured under normal operation.
4The measurement is repeated under single-fault conditions.
5Results are compared with the threshold values.

Touch Current — IEC 60335 Acceptance Criteria

The acceptance criterion is the maximum touch-current values in the product standard; different limits apply depending on the network type.

Evaluation of Results

The measured value depends on the network used; the network type must always be stated in the report. Fault-condition values are evaluated separately.

Touch Current — IEC 60335 Report

Applied standard and measurement network
Supply conditions
Contact points and fault conditions
Measured currents and limits

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 authorisations

Related Regulations

LVD 2014/35/EU
MDR 2017/745 (medical)

Electrical Safety — What Does This Testing Field Cover?

The section below describes the field that the Touch Current 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 Touch Current — IEC 60335

According to which standard is Touch Current made?

Touch Current is executed in scope IEC 60990, IEC 62368-1, IEC 60335-1, IEC 60601-1, 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 Touch Current apply to?

Mainly applied to Information-technology equipment, Audio and video equipment, Household appliances, Medical devices and Power supplies. Whether your product is included in the scope is determined by examining its technical specifications and intended use.

Under what conditions is Touch Current done?

The determining parameters are: Measurement network — Weighted networks defined in IEC 60990 (perception/reaction, let-go), Supply voltage — Defined in the standard; a multiple of rated voltage and Conditions — Normal operation and single-fault conditions. 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 Touch Current?

Accessible surfaces must be determined, The device must be brought to steady-state temperature and Fault conditions must be planned. The number of samples is determined according to the product standard and the scope to be reported.

How long does Touch Current take?

Depends on the number of points and conditions; typically half a working 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 Touch Current result called "appropriate"?

The acceptance criterion is the maximum touch-current values in the product standard; different limits apply depending on the network type.