Isolation Transformer

I possess a home made isolating transformer with a variac.

The output socket and safe-block each has an earth. Use is of course optional.

But that is clearly not the case. In the kit shown in the original image.

The secondary was NOT connected to ground. That is the whole f****ng pint!

I suspect that you an cursitor simply haven't understood how that piece of kit in the image was actually wired,

In article snipped-for-privacy@4ax.com, Dave W snipped-for-privacy@yahoo.co.uk> scribeth thus

Had a system like that in a TV repair workshop many years ago but from time to time someone would break the aerial isolator panel and bypass the damm thing course all the aerials were fed of a distribution amplifier which was earthed to mains earth!..

In the end there was a aerial isolator panel for each aerial lead form the aerial amp in case the one of the TV was borked!...

Not a lot of fun if you were an aerial rigger that and the ladder in soft damp ground tied to the roof ladder and the wires in the mains plug arse about face!..

What are they both connected to? Surely there is only one Earth.

Don't be silly. Earthing or not is orthogonal to the function of an isolation transformer.

Typically you would use it to keep a metal frame at earth potential for safety

Without connecting it to the output secondary at all.

Quite, there is only one earth. And relying on the earth pin in the plug. The earth socket pin and the earth on the safe-block would be the same earth.

If I want a floating earth that is simple to arrange, simply don't connect it.

The reason I did this was that I could earth specific parts of an equipment's power supply so that measurements and scope waveforms were taken wrt earth, and of course the equipment chassis would be earth too.