Cleaning packs

I'd say a slightly high voltage than that. But certainly for mains, or CRT voltages or... And of course never hold the chassis in one hand while pokeing about with the other. If you do, then if you happen to touch an high voltage point the current _will_ take the most dangerous path it can. Particularly for self-tapping screws and threaded things that are large-diameter compared to the pitch (e.g. locking rings in optical systems) Related to that, if you have a number of screws holding something down, fit and tighten them in a diagonal pattern. Many older books descried this as ;ike torquing down the cylinder head on an engine' but I guess few people have done that these days. This is so ingraained in me that I even do it for things like the covers on plastic project boxes. -tony