This is a natural reaction - and even an 'Enforcement Officer' in the UK has produced a book suggesting that you can do a safety review and apply the CE Marking for safety using only ONE template (which happens to be his book!!!).
Consider the number of PRODUCT standards written - these reflect the accepted degree of protection (Operator or User) for each product under specified operating conditions and accepted uses. Simplistically USE will change safety. (Indoor - Outdoor and Underwater lights). Using the SAME STANDARD approach there is a VERY REAL risk of over design being forced upon manufacturers and product costs soaring. More subtle situations exist. We have recently obtained a UL Listing for a UK product (The First Pocket CDR) - the test lab suggested '065 but I insisted upon '950 because (amongst other things, the Creepage and clearance distances between the two standards is not compatible and as a result '950 provides a higher level of protection for the user). There is no issue when two '950 products are interconnected, but the user safety of the '950 product MAY BE REDUCED if a non'950 product is connected. AGAIN - consider SHORT CIRCUIT protection and investigation. for a domestic product the issues are simple - does the fuse blow before the cable melts and catches fire...... For SWITCH GEAR the issues are significantly different. Do the busbar fixings survive the stresses caused by adiabatic heating or do the bus bars rip themselves out of the enclosure and beat the operator to death???!! It is for these and many other reasons that there are SO MANY STANDARDS. What I have tried to do in my training courses and material is to teach engineers, not to generalize, but to think laterally of the potential problems and issues - that is how to develop the probing - enquiring and disbelieving mind necessary to become expert in the world of product safety. Best regards Gregg -----Original Message----- From: [email protected] [mailto:[email protected]]On Behalf Of Rich Nute Sent: Wednesday, September 26, 2001 1:02 PM To: Product Safety Technical Committee Subject: Re: Applying the appropriate ENs > It is the primary end use of the product that dictates the standard(s) > required. Unfortunately, this archaic and provincial view on the part of standards organizations that standards should be per product has created problems that most of us would like to avoid. Consider product safety. The safeguards required for protection against electric shock, for example, are independent of the product. Although we have product standards for hair dryers and for computers, the requirements for safety are common. Rather than address products, safety standards need to address hazards. While the products I deal with are computer peripherals, I had the opportunity the other day to attend a seminar on insulation diagrams used for medical products. The interesting fact is that the seminar did not address anything unique to medical products. Rather, it addressed a tool -- insulation diagrams -- that is equally applicable to my products and all other products where protection against electric shock is required. Indeed, the insulation diagrams of some of my products are identical to the medical product insulation diagrams presented in the seminar! (For the purposes of electric shock, the only differences between a computer peripheral and a medical product are the limit values used for the various parts of the equipment.) I would like to see safety standards based on the hazards. I would like to see separate, independent safety standards for electric shock, electrically- caused fire, thermal injury, moving parts (kinetic energy), etc. (Note that the USA and Canada already have independent safety standards for x-radiation and electromagnetic radiations. These standards are based on the hazard, not on the product.) Doing this job is not easy. If you compare product safety standards, you will find much in common, but you will also find differences. It is these differences that cause difficulties in writing a generic safety standard. Committees are reluctant to discard any requirement on the basis that products built to the standard have a good record. Likewise, committees are reluctant to introduce a new requirement because it may cost manufacturers more money in the product design, and products built to existing requirements have a good record. Virtually no one is willing to invest in research in product safety in order to make decisions on whether or not a safety requirement is an effective safety requirement. There are a few -- very few -- exceptions. The basis of IEC 664 (dimensioning of insulation) is research. More recently, the CES has published research data on TV fires. Our EMC colleagues don't appear to be so hampered. They have peer-reviewed journals, and annual symposia reporting on the results of research. A bunch of IEEE folks are doing their best to set up an IEEE Product Safety Society. I would hope that this society will serve to improve product safety, to bring it to the same level as EMC. Best regards, Rich ------------------------------------------- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. 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