Hero999 said:
Ideally yes but how is an earth free environment practically possible?
I don't see how it is.
Your soldering iron's tip is earthed.
Only if you earth it!.
Even the concrete floor will conduct electricity to some degree (it absorbs water).
That's assuming a concrete floor?, which it isn't, and being at ground level?, which it isn't. The floor is a Pitchmastic type of substance (not exactly sure what?), but it's non-conductive, and has rubber matting over it as well.
I can stand on the floor and hold a 240V live wire perfectly safely - and usually do a couple of times a year.
The metal bench you're working on is earthed.
Who uses metal work benches? - I certainly wouldn't entertain them!.
Why would a chair be earthed?, why would you assume it's even made of metal?.
Even the screws on the plug socket are earthed!
Possibly! - obviously depending entirely on the wiring, and for an earth free environment they wouldn't be.
What happens if a conductor shorts to the scope's cause?
What happens if it shorts to some where else? - you can't just randomly assume something is going to happen like that, and there are plenty of random conductors shorting to things that are more dangerous in an earthed environment.
But if it does short to the scopes casing nothing happens, because it's not earthed.
The case will either become neural or live with respect to the other circuit.
But is completely of no consequence, as there's no earth reference to get a shock from.
The isolation transformer isn't dangerous, you obide by normal safety practice and don't touch the circuit being tested.
Normal safety practice doesn't allow you
not to touch the circuit in a service environment - although you obviously take great care in everything you do. Keeping one hand in a pocket is always a good idea, but earthed or not makes little difference to that (apart from you're more likely to get a shock if you touch a live conductor in an earthed environment).
Your floating scope's at mains potential is a death wish, as soon as touch it the current will find a path to earth where you leaset expect it and kill you.
There is no earth, so that isn't possible - why do you find that so hard to understand?.
The only way you can safely not connect your scope's case to ground it if you run both it and what you're testing from an isolation transformer but in practice, it's only really important you run the device under test from an isolation tranformer.
You appear to have been 'brainwashed', you've been told there's only one possible way to do something, and can't think 'outside the box' for alternatives.
There are normally multiple ways to do most things, with varying advantages with each - you are stuck in a single minded approach and can't conceive that there may be alternative methods just as good, and possibly better.
In an attempt to prove your single minded point of view you have made loads of completely incorrect assumptions in your last post - just think of what earthing is for, and what it's supposed to do, and why it's done like it is. It's not perfect, it has major flaws, but for a
domestic environment it's probably the best choice - I wouldn't deny that!.
My only reason for repeatedly posting in these threads is to try and make people understand that blindly following a single idea isn't always the best way - use your brain, consider the alternatives, don't be a sheep!.
Like I've said everytime this has come up though, if you don't understand it, then
DON'T DO IT!.