SAFETY: Isolation transformers

Hi,

does someone use isolation transformer(s) ? Is test equipment (osciloscope...) connected to that too or not ? How much power should I need for tube and solid state circuits ?
Is good choice to use two hallogen transformers connected in reverse (like PSU in G7). Is ground used from AC outlet ?

Yes, I use a large isolation transformer for all my test-bench instruments and power outlets. It's a cheap life-insurance when you have to deal with unpredictably-damaged gear.

You can't use two transformers back to back, as the voltage will vary too much under different loads.

Large isolation transformers can often be found cheaply second-hand.

Get at least a 500W type.

There are vario-transformer/isolation transformer combinations that are very good for testbenchs also.

Jakob E.

[quote author="gyraf"]Yes, I use a large isolation transformer for all my test-bench instruments and power outlets.
Jakob E.[/quote]

I found in the "tek" site this PDF:

http://www.cankar.net/tek.pdf

And I found also, that just tested gear should be connected to the isolation transformer.
I didn't quite understand this, because Isolation transformer has two wires input and two wires output. Where the ground of tested gear should be connected in that case ?

Keeping with the theme,should I use a GFI?.
Thanks
Aharon