Thanks for all the good feedback and questions you have kindly submitted - I have the following new information.
I found the person responsible for maintaining the HiPot system and, (to my surprise) he can not remember any report of a shock or injury at the HiPot tester except for a close-call several months ago where horse-play was involved. I just discussed this with the plant safety officer and apparently this is a case where the story got worse each time it was repeated. So while there may be a hazard, there is no documented case of injury within memory of the HiPot supervisor or any formal injury report given to the safety officer. However, there was some useful discoveries made nonetheless. The tester is an aging Rod-L system composed of three units: a model M150AC HiPot tester (cal is current), a model M30 ground continuity tester (cal also current), and a GPIB controller module. Only the M30 carries the UL label, none was found on the M150AC HiPot generator. The entire system is controlled from a recently redone in-house application on a PC, the new PC application allows HiPot failures to be immediately logged into the production database. This system requires a two-step operation, continuity and hipot, by manually replugging the power cord into each instrument. The test order was not established in the time I had available (other meetings...). The system shares workspace with other manufacturing and test functions, placing the operator potentially elbow-to-elbow with co-workers, and placing them at some risk of injury. The HiPot tester does not appear to have a specific ground check safety feature, no evident warning indicator exists on the HiPot unit itself (aside from pass/fail) - but the M150AC user manual is currently missing.... According to the M30 manual, the continuity tester is wired to the M150AC correctly. A new ground clamp and cable was added recently to replace the original one that was nearly falling apart, and it appears to be well built. This system fails HiPot on occasion, while the same products subsequently pass on a portable HiPot tester that also bears a current calibration sticker. All this, and we're about to open another production line.... Next Steps The entire tester will be moved tomorrow to a new dedicated bench with the floor space clearly set-off by safety yellow/black tape (only the operator is permitted to enter). Some colorful High Voltage warning signs will also be posted above the workspace. Written procedures exist (as per ISO 9002) but they need to be reviewed; and I will recommend augmenting the written procedures with a video training tape. I have concluded that this system is too old, can't support our increasing manufacturing volume any more, and is now a liability (read that PITA). I have decided to call for the ASAP purchase of a new modern test system; the safety officer and the HiPot supervisor appear to be happy with the idea. Management is expected to heartily endorse the proposal. Best Regards, Eric Lifsey National Instruments [email protected] on 01/08/98 10:53:47 AM Please respond to [email protected] To: [email protected] cc: (bcc: Eric Lifsey/AUS/NIC) Subject: HiPot Testing - Operator Safety Precautions? We're looking into a problem where, on occasion, our manufacturing operators are getting zapped while operating a production HiPot test station. (Just how this happens is yet to be determined.) I've reviewed literature on HiPot equipment, but nothing I have suggests any operator safety features are available. I can imagine some simple methods to prevent this, but I thought it might be worth soliciting ideas from those that have successfully solved this particular problem, since it may be a more common problem than most of us realize. Regards, Eric Lifsey Compliance Engineer National Instruments
