On Tue, 13 May 1997 [email protected] wrote: > (DK, FI, NO, SE). Transient protection components shall be installed > in such a way that insulation for protection against electric shock > will not be bridged. This means that transient protection components > must not be connected to protective earthed parts in pluggable > equipment or to other accessible parts. > > I think the concern here is the possibility of not having a good > ground, and then if the over voltage is shunted to ground, the chassis > could become hot. > > Is this a valid concern? It sounds like a "double fault" scenario to > me. If so, does anyone have an alternative solution?
Double component faults shouldn't be confused with double insulation. Two series components failing is not an unusual situation, and can occur over the life of the equipment without being noticed (until someone gets a nasty shock). As for myself, I would accept holding onto an insulator with 230V on the other side (I do turn on light switches). I would never knowingly hold onto the other end of a surge arrestor with 230V connected even if this was guaranteed not to conduct at that voltage. I think your only choice in this situation is to ensure that the isolation transformer is capable of withstanding the likely surge voltage. Just my views. Bruce Hunter
