[Kevin Kuehn]

Problem with the newly manufactured units is that they likely will have the 3 wire ground lug follow through to the mains ground. So they are not truly isolated in that respect, which would be a problem if you're attempting to isolate a piece of test equipment that has a third wire ground on it's power cord. You could potentially have a bad day(hopefully would blow a circuit breaker) if your modern scope were plugged into the isolation unit while also connected to a hot chassis. However a little DIY modification(snip snip) would easily remedy that situation.