Subliminal message for RJR, 'TRMS meter with non contact voltage detection...' Sorry for the added temptation, but I was looking at one of these the other day and it looked like a neat gadget that we should all have ().
I sure don't want to ruin your free hair curl though. Go ahead and get that first, having to pay for one of those could be more than the cost of the meter?
Also, I don't know about the happenings with the 400HZ, but I can tell you what happens when the maintenance man adds some 277 fluorescent fixtures to an office and switches the neutral instead of the hot and you go to add a motion sensor relay (energy saving deal) using the light switch for the breaker because no one knows where the breaker is for that room.
It was a truly 'enlightening' experience, similar to GRJ's holding on to the electrical box with one hand and the wire with the other to verify voltage status on the circuit.
We had done a couple hundred rooms prior to that one without a problem. I started using one of those thingies that Mike CT stuck in the receptacle on each and every single wire up there right after that for the rest of the building.