A recent recall of surge protectors brings up some interesting issues and discussions. MOVs are a common item used to clamp surge voltages. However, industry has found that MOVs overheat when subjected to many surges and also overvoltage conditions. Here’s a good report of one firms findings – http://www.circuitbreakersblog.com/tag/metal-oxide-varistors/. UL addressed the issue in the latest edition of the Standard – UL1449 Surge Protective Devices. However, the requirements went into effect in 2007, then again 2009. This latest recall is for 15 million surge protectors by Schneider Electric – http://www.cpsc.gov/en/Recalls/2014/Schneider-Electric-Recalls-APC-Surge-Protectors/. They were all built and complied to the old UL Standard. How many more surge protectors are out there that may have an issue? Should our Standards start to include end of life failure mode confirmations?
There are a couple of new IEC Standards incorporating Hazard Identification and Risk Assessments (IEC62368-1 is the new Hazard Based Safety Engineering Standard for IT Equipment, IEC60601 3rd Edition is the new Risk Management based Standard for Medical Equipment, ISO12100 is the new Hazard ID and Risk Assessment based Standard for Machinery going to Europe, and there are more on the way). Should all our Standards be moving in that direction? It seems it’s happening internationally. Should it come to the USA? Give us your thoughts and feedback.