Hazard-based standard 62368-1 Classroom – Questions and Answers
Do you want to know more about the hazard-based standard 62368-1? From this issue onwards, we will share some knowledge on the standard in a question and answer format. If you would like to further discuss this topic with our technical experts, you may join our LinkedIn group – UL Hazard Based Safety Engineering or contact Kevin Ravo, director for technology, standards and regulations, UL global high-tech industry.
For more information regarding 62368-1, please also visit our Web site – www.ul.com/62368, which also provides access to over 30 Technical Briefs on 62368-1.
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Q: Energy sources are classified in IEC 62368-1 based on the maximum levels of energy available from the source. When may, if ever, an energy source classified as Class 2 exceed Class 2 limits?
A: IEC 62368-1 does not permit a Class 2 energy source to ever exceed Class 2 limits when measured per the conditions stated in the Standard. According to the description of a Class 2 energy source in 4.2.2, a Class 2 energy source is an energy source with limits exceeding class 1 limits, but not exceeding class 2 limits under normal operating conditions, abnormal operating conditions and single fault conditions. Therefore, in order for an energy source to be classified class 2, it is not allowed to exceed the class 2 limits under the stated conditions. It is acknowledged the first sentence in 4.2.2 leads in with the phrase “Unless otherwise specified…”, but there currently are no exceptions in the Standard. However, it is also noted that a class 1 energy source is allowed to rise above class 1 limits and into class 2 but not exceed class 2 limits under single fault conditions. However, this type of provision for ever exceeding the inherent class limits for a particular class is only allowed for class 1, not class 2.
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Q: What are the terms used in IEC 62368-1 for the types of persons who use and/or interface with equipment and are considered into the determination of the types of safeguards that are required to be associated with equipment covered by the Standard? (A: User, Instructed Person, and Service Person; B: Ordinary Person, Instructed Person and Skilled Person; C: Operator and Service Person or D: Operator, Instructed Person and Service Personnel)
A: B - Ordinary Person, Instructed Person and Skilled Person See sub-clauses 0.2 and 3.3.8.
