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EN 60335-1 Amendment Mandates Additional Testing

Safety Compliance Requirement For Household Appliances And Similar Electrical Equipment.

May/June 2008

Authored by Dieter Baldamus, (Newtown, CT) Senior EMC Engineer

As of October 1, 2007, EN 60335-1 amendment mandated additional EMC testing for applicable household and similar electrical appliances.

In general, household and similar electrical appliances are required to comply with emissions standards CISPR 14-1(EN 55014-1), IEC 61000-3-2 (EN 61000-3-2) and IEC 61000-3-3 (EN 61000-3-3) and to the immunity standard CISPR 14-2 (EN 55014-2). As the number of devices incorporated with electronic sensitive components to control safety mechanism increased, the need to ensure safety became crucial. So, amendment 1 of EN 60333-1 was instated to mandate additional EMC tests to ensure safety of the devices when subjected to electromagnetic interference.

Not all household and similar electrical appliances are subjected to the new safety requirement. As described in section 19.11 of the standard, only appliances containing a protective electronic circuit are subjected to additional EMC tests. The definition for a protective electronic circuit (as provided in clause 3.9.3 in Amendment 1 of IEC/EN 60335-1:2002) is an "Electronic circuit that prevents a hazardous situation under abnormal operating conditions. Parts of the circuit may also be used for functional purposes."

In general, appliances which incorporate electronic controls with sensing and responsive circuits, which are used for safety reasons are subjected to additional tests under clause 19.11.4. In other words, where the protection against a hazardous situation under abnormal operating conditions does not rely on the operation of fuses, circuit breakers, thermal cut-outs, thermal fuses etc. but on the operation of electronic circuits, such appliances must be tested according to clause 19.11.4.

There is a wide range of appliances which can rely on proper operation of protective electronic circuits, for example: garage door operators, kitchen appliances, battery chargers, spas and other motor-operated, heating and combined appliances. Appliances having a switch with an off position obtained by electronic disconnection, or a switch that can be placed in the stand-by mode, are also subjected to the test of clause 19.11.4.

During and/or after testing according to clause 19.11.4, compliance with the standard requirements is verified according to clause 19.13. The test levels required for safety compliance are higher than the ones required under the CISPR 14-2 standard and are carried out after the electronic protective circuit has operated during a relevant test of abnormal operation as described in clause 19. The levels and basic standards are:

• Electrostatic Discharge in accordance to IEC 61000-4-2, level 4(±8kV Contact Discharge, ±15kV Air Discharge). Ten discharges having a positive polarity and ten discharges having a negative polarity are applied at each pre-selected point. (Section 19.11.4.1 of the standard).
• Electromagnetic Field Immunity test in accordance to IEC 61000-4-3 level 3 (10V/m), with a dwell time for each frequency is to be sufficient to observe a possible malfunction of the protective electronic circuit (Section 19.11.4.2 of the standard).
• Electrical Fast Transients test in accordance with IEC 61000-4-4, level 3 (±2kV) for signal and control lines and level 4 (±4kV) for power supply lines. The burst shall be applied 2 minutes at each polarity. (Section 19.11.4.3 of the standard).
• Surge Immunity in accordance to IEC 61000-4- 5, five positive and five negative discharges at level 3 (±2kV) coupled between each power line and five positive and five negative discharges at level 4 (±4kV) coupled between each line and ground. This section has some considerations regarding heating elements and surge arresters (Section 19.11.4.4 of the standard).
• Conducted Immunity test in accordance to IEC 61000-4-6 (10Vrms) and between 0.15MHz and 80MHz, with a dwell time for each frequency sufficient to observe a possible malfunction of the protective electronic circuit. (Section 19.11.4.5. of the standard.
• Voltage Dips and Interruptions in accordance with IEC 61000-4-11, with dips and interruptions specified in table 1 of the standard which are:
• 0% during 1 cycle, at zero crossing of the supply voltage.
• 40% during 10 cycles (if appliance runs at 50Hz) or 12 cycles (if appliance runs at 60Hz) and at zero crossing of the supply voltage.
• 70% during 25 cycles (if appliance runs at 50Hz) or 30 cycles (if appliance runs at 60Hz) and at zero crossing of the supply voltage.
• 80% during 250 cycles (if appliance runs at 50Hz) or 300 cycles (if appliance runs at 60Hz) and at zero crossing of the supply voltage.
• Harmonics and Interharmonics Immunity test in
  accordance to IEC 61000-4-13, test level class 2
  as described in the standard.

In general, it is expected that appliances should not undergo a dangerous malfunction and there should be no failure of protective electronic circuits if the appliance is still in operation. Additionally, appliances tested with an electronic switch in the off position or in stand-by mode, should not become operational.

The EMC and safety division of TÜVRheinland® has the capability to perform and evaluate the additional testing requirements to meet compliance of household and similar equipment in accordance to the new amendment 1 of the EN 60335-1 standard.

For more information, please call 1-TUV-RHEINLAND (1-888-743-4652).