My recollection is that a number of UL standards that explicitly excluded reliance on hinges as bonding conductors.
For instance, UL 1459, 3rd ed, explicitly states that hinges and bearings can not be used as current carrying parts. This was interpreted to apply under normal and fault conditions. IEC 60950-1 relies on the generic 'principles of safety' concept. For instance, ยง0.2.1, second paragraph, states: "Bare parts which have to be touched or handled should be at earth potential or properly insulated." It's up to the designers to ensure a reliable means is provided to meet the concept in this principle. At least with IEC 60950-1 (and its preceding versions/editions), the intent was to not be a prescriptive standard and rely more on 'good engineering practices.' Failure to do so is at the decision-maker's risk. Sometimes risks pay off financially and sometimes they don't. One can only hope that no one is hurt in the meantime. Regards, Peter L. Tarver, PE [email protected] This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: [email protected] with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: [email protected] Dave Heald: [email protected] For policy questions, send mail to: Richard Nute: [email protected] Jim Bacher: [email protected] Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
