Isolating Distance

I think that it is intentionally nebulous, to allow for local codes.

Being a KISS fan, (not the band), I would read that statement to mean: Don't have live wires hanging out, and make sure that the "isolators" are actually "isolating", and not tied into another circuit. In other words, an "isolater" is pretty pointless if it's not doing it's job.

I got bit hard one time by 240 volts...someone thought that a red tag was acting as an isolator, and didn't shut down the damned juice.

The required distance between the open contacts is dependent upon the voltage class of the device in question. More than likely that is whet they are referring to. You will have to check the appropriate IEC standard for the isolator to see what the minimum distance must be.

I have already referred to the relevant IEC Standards. But, even in IEC 60050-441-14-05, it is only vaguely mentioned that "a disconnector is a "mechanical switching device, which provides, in the open position, an isolating distance in accordance with specified requirements".

I want to know what are the specified requirements of an isolating distance?

Here is a free download that might have your answer.

http://www.scribd.com/doc/46465954/GN2-Isolation-Switching