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EN62368-1 Hazard-Based Safety Engineering

Friday, October 06, 2017

HazardIEC TC108 is the technical committee that advises CENELEC on the topic of standardisation of safety for audio/video and similar technology, information technology and communication technology equipment. Together they have produced a new standard which incorporates ITE, Audio/Video and communications equipment with initial input from ECMA TC12. The call for the new standard has been mostly driven by devices like mobile phones that are a combination of all three - it is a mini computer, audio video support and of course a communication device. This calls for an integration of the IEC60065 & IEC60950, however the new standard is NOT simply a merger of IEC60065 and IEC60950.

IEC62368-1, Ed 1.0 was written in 2010 and is a voluntary alternative to the ‘60065 and ‘60950 standards. Edition 2 was published in February 2014.

The standard covers equipment such as: PC’s, amplifiers, digital cameras, TV’s, mobile telephones, power supplies, network infrastructure equipment, battery powered devices, photocopiers and musical instruments. For the standard to encompass all of these different products, it must be technologically independent and more hazard based. In other words, based on good engineering principles as opposed to product specifics. This results in a more performance based approach, such that the products are qualified on test results as opposed to construction regulations.

Each hazard clause is laid out individually stating; the objective of the clause, the energy source and the supplemental and reinforced safety measures, location of the safeguard - including its properties and parameters and finally the safeguard tests to verify hazard mitigation.

Injury only occurs when the hazard (predominantly electrical sources of energy, but can be others; heat, fuel, mechanical, radiation, etc.) has a transfer mechanism that permits the transfer of significant energy for a significant time to the body. The energy sources are split into 3 classes, detailed below:

Energy Source




A class 1 energy source has levels not exceeding class 1 limits under:

  • Normal operating conditions
  • Abnormal operating conditions that do not lead to a single fault condition
  • Single fault conditions that do not result in class 2 limits being exceeded. Under normal operating conditions and abnormal operating conditions, the energy in a class 1 source, in contact with a body part may be detectable, but is not painful nor is it likely to cause an injury

A class 2 energy source has levels exceeding class 1 limits and not exceeding class 2 limits under:

  • Normal operating conditions
  • Abnormal operating conditions
  • Single fault conditions

The energy in a class 2 source, under contact with a body part, may be painful, but is not likely to cause an injury. For fire, the energy in a class 2 source can cause ignition under some conditions.

A class 3 energy source has levels exceeding class 2 limits under:

  • Normal operating conditions
  • Abnormal operating conditions
  • Single fault conditions or any energy source declared to be a class 3 source

The energy in a class 3 source, under contact with a body part, can cause injury. For fire, the energy in a class 3 source may cause ignition and the spread of flame where fuel is available.

Safeguards are classified in three levels:

Basic safeguards - effective under normal and abnormal working conditions.­

Supplementary safeguards - effective in the event of a single fault of any part, including the basic safety guards

Reinforced safeguards - effective under normal & abnormal operating conditions and single fault condition

Each of these are graded as follows:

  • Equipment safeguards - inherent in the product and not reliant on the user to implement or influence the effectiveness of those safeguards
  • Installation safeguards - the installer must be competent in installation, as a safeguarding characteristic is achieved with correct installation
  • Behavioral safeguards - when the energy source is accessible to the user


















How does it compare with EN60950? Most of the changes are descriptive, for example: SELV (safety extra low voltage) and LCC (Limited Current Circuit) are covered by Energy Source Class I. TNV (Telephone Network Voltage) is described as an external circuit. The ‘Service person’ becomes ‘Skilled person’ and ‘User’ (operator) / ‘User with limited training’ becomes an ‘Ordinary person’ or ‘Instructed person’ respectively.

Hazard 2

Transition dates to this new standard is expected in March 2019, aligned with the 5-year withdrawal of ‘60065-1 and ‘60950-1.



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