IEC 62368-1:2018 is a product safety standard that classifies energy sources, prescribes safeguards against those energy sources, and provides guidance on the application of, and requirements for, those safeguards. The prescribed safeguards are intended to reduce the likelihood of pain, injury and property damage due to fire.
The standard is applicable to the safety of electrical and electronic equipment within the field of audio, video, information and communication technology, and business and office machines with a rated voltage not exceeding 600 V.
The situation in Europe and with CE Marking
Manufacturers and distributors of devices for the European market have been uncertain for some time about which standard applies to them.
EN IEC 62368-1:2020 was published as an ‘EN’ standard on 06 January 2021, superseding EN 62368-1:2014. However, a reference to EN IEC 62368-1:2020 has not been published in the Official Journal of the European Union (OJEU) and therefore does not offer a Presumption of Conformity (PoC) to the Low Voltage Directive (LVD), or any other Union harmonization, or ‘CE Marking’, legislation.
As a consequence, EN 62368-1:2014 is still published in the OJEU offering PoC to the Low Voltage Directive, and as of June 2022, no end date for this PoC was listed.
The CENELEC site for EN IEC 62368-1:2020 indicates that it will be superseded by EN IEC 62368-1:2022 based on the, yet un-published, edition 4.0 of IEC 62368-1. Although expected for January 2023, it is not clear when EN IEC 62368-1:2022 will be published in the OJEU under the LVD.
Technical changes which may affect manufacturers
This third edition of the IEC 62368-1:2018 cancels and replaces the second edition published in 2014 and constitutes a technical revision. The notable technical changes in respect to the previous edition include:
Whilst the scope remains largely the same, large equipment installed in restricted access areas is now also covered, although additional requirements may apply to equipment having large machinery aspects. However, the scope clarifies that it does not apply to equipment with non-self-contained hazardous moving parts, such as robotic equipment. Personal care robots are also not covered by the standard.
The scope also states that the application of IEC 62368-3 (safety aspects for DC power transfer through communication cables and ports), is now required for equipment having the capability to supply DC power over commonly used communication cables, such as USB or Ethernet (PoE). It should be noted that CSA C22.2 No. 62368-1:19 & UL 62368-1, Ed. No. 3, include a national difference (1DV.2.3) which modifies this requirement.
Additional requirements for outdoor equipment (Annex Y)
Additional requirements, which are specifically relating to construction requirements for outdoor enclosures, have been outlined in annex Y. Overall, this is the same as IEC 60950-22 Outdoor ITE and reflects present practice but the requirements have been made hazard based.
These include general requirements; requirements for resistance to UV radiation; UV light conditioning test; resistance to corrosion; gaskets; protection of equipment within an outdoor enclosure, including protection from moisture and dust; and mechanical strength of enclosures.
New requirements for optical radiation (Clause 10.4)
The requirements relating to safeguards against optical radiation from lamps and lamp systems have been significantly rewritten to help clarify the requirements and explain how to address each form of optical radiation hazard type.
As many of the requirements have been derived from the horizontal standards, they are not expected to cause a major impact to manufacturers.
Addition of requirements for insulating liquids (4.4.4, 5.4.12, 6.4.9)
Whilst the standard continues not to address the use of insulating liquids as a replacement for basic, supplementary or reinforced insulation, it does now contain requirements where an insulating liquid displaces air comprising a safeguard.
Clause 4.4.4 ties together the requirements for insulating liquids and points to the other relevant clauses in the standard.
Clause 5.4.12 addresses the use of liquids as an insulator to protect against electrically caused injury. The clause requires the liquid to not break down due to overvoltages, including transients, that enter the equipment, and peak voltages that may be generated within the equipment.
The requirements around pressure relief and containment of hazardous substances, and for the container of the liquid, are also addressed in clause 22.214.171.124.
It should be noted that creepage and clearance distance requirements apply to the equipment both with and without the insulating liquid present, and the loss of the insulating liquid needs to be considered as an abnormal operating condition.
Requirements relating the potential flammability of insulating liquids have been introduced in clause 6.4.9.
Addition of requirements for work cells (126.96.36.199)
Work Cells are defined as a 'space within the equipment of such size that a person can enter completely or partially (for example, entire limb or head) for servicing or operating the equipment and where mechanical hazards may be present'. Requirements for work cells have been introduced in clause 188.8.131.52, however these are consistent with those in IEC 60950-23 covering Large Data Storage Equipment, so should not take manufacturers by surprise.
Measures to protect persons in the work cell are achieved through the prevention of access to dangerous (class 3) moving or other parts through the use of safeguards such as interlocks, barriers, signals, procedures and training.
Protective mechanisms may be overridden by skilled persons, where appropriate interlocks and emergency stop systems and visual indicators are provided in accordance with 184.108.40.206.2.
Addition of requirements for wireless power transmitters (9.6)
Clause 9.6 has been introduced to address the thermal hazards associated with wireless power transmitters (e.g. near field wireless chargers), resulting from the heating of foreign metallic objects placed near the transmitter. The test requires that a foreign metallic object in contact with the transmitter during charging does not exceed 70°C.
Addition of requirements for fully insulated winding wire (FIW) (G.5.3.4)
The introduction of clause G.5.3.4, allows transformers with FIW to be used in equipment within the scope of this standard. The requirements are similar to those introduced by AMD1:2013 of IEC 61558-2-16:2009, which allows the use of FIW wires in switch mode power supplies (SMPS).
Alternative method for determination of top, bottom and side openings for fire enclosures (220.127.116.11)
Requirements for top, bottom and side openings for fire enclosures have been revised so that they more closely match the previous requirements in 60950-1, including the reintroduction of the side openings requirements. The requirements in the previous version of 62368 (2014) caused issues for some products which were previously compliant to 60950-1. A number of clarifications have also been made to allow for a more consistent application of the standard, including to what constitutes top, bottom and side openings, and to help identify the applicable requirements and testing. The requirements addressing the integrity of the fire enclosure and the compliance criteria remain the same.
Alternative requirements for sound pressure (10.6)
Safeguard requirements for protection against long-term exposure to excessive sound pressure levels from personal music players, earphones and headphones are specified in clause 10.6.
The dose based system to reduce the level of sound energy that an individual receives without putting their hearing at risk has been introduced in clause 10.6.3. This system aims to limit the Calculated Sound Dose (CSD) to below 80 dB for a maximum of 40 hours duration, through guidance and warnings to the user. Requirements to limit the momentary exposure level (MEL) are also provided in clause 10.6.3.3.
Compliance can be achieved using either 10.6.2 or the newly introduced method in 10.6.3. However, the standard encourages manufacturers to implement 10.6.3, as it is expected that this will be the only method of compliance available in the future.
Other changes to note
Whilst the above represents the most notable changes to the standard, it is not an exhaustive list. Other clauses have also been amended to a greater or lesser extent, and products will require re-testing to ensure they meet the requirements of the latest version of IEC 62368. These include:
4.1.6 Orientation during transport and use
5.8 Backfeed safeguard in battery backed up supplies
6.4.5 Control of fire spread in PS2 circuits
6.4.6 Control of fire spread in a PS3 circuit
18.104.22.168 Separation by distance
6.5.1 Internal and external wiring
6.5.3 Internal wiring for socket-outlets
8.6.1 Stability of equipment
9.3 Touch Temperature Limits
9.4 Safeguards against thermal energy sources
Annex S.2 Flammability test for fire enclosure and fire barrier integrity
Annex X Alternative method for determining clearances for insulation in circuits connected to an a.c. mains not exceeding 420 V peak (300 V RMS)
IEC 62368-1:2018 - What do manufacturers need to do?
Manufacturers need to review their documentation to ensure their product is tested to the latest version of the IEC 62368-1:2018 and perform additional testing where relevant to bring them up to the current standard and ensure compliance. It may also be necessary to update technical documentation, test results and declarations to reflect the new standard and demonstrate conformity to legislation.
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