Oscilloscope probes and high voltages (upto about 500v)

[cowasaki]

I use a large isolation transformer which plugs into a bulb current limiter and then a variac when necessary.

If I want to check high voltage lines I usually discharge, attach a lead and switch on so that I am ultra safe. However there are times when I want to check live items VERY CAREFULLY

I have seen people using standard probes but would rather be safe than sorry. Should I get high voltage probes? Do I need differential probes with my setup? What is safe? I understand the earth potential issue but I work earth isolated.

[tggzzz]

I understand the earth potential issue but I work earth isolated.

How, exactly, do you completely isolate yourself from the earth?

Be aware that isolation transformers are not a panacea; you can still kill yourself because you are using it incorrectly, or even if you are using it correctly. Ditto RCD/GFCI.

Apart from that, I'm not prepared to give off-the-cuff advice on a topic like this. There's too much chance I might forget something, I might explain it poorly, you might misunderstand, you might do something I hadn't anticipated...

The references in https://entertaininghacks.wordpress.com/library-2/scope-probe-reference-material/ might be of some help.

[PKTKS]

I use a large isolation transformer which plugs into a bulb current limiter and then a variac when necessary.

So do I but my bulbs are "after" the VARIAC.
My order for the DUT is: transformer (which is a 110 to 220) + 220VAC VARIAC + BULB(s)

AND ALL MY INSTRUMENTS HAVE DEDICATED  ISOLATED TRANSFORMERS.
Yes they are floating
and yes I am aware of the risks and implications

If I want to check high voltage lines I usually discharge, attach a lead and switch on so that I am ultra safe. However there are times when I want to check live items VERY CAREFULLY

I have seen people using standard probes but would rather be safe than sorry. Should I get high voltage probes? Do I need differential probes with my setup? What is safe? I understand the earth potential issue but I work earth isolated.

Yes - YOU **SHOULD** get at least a 100x probe for anything rated above 200V
That will raise your input impedance quite enough to protect your scope input

WILL NOT RELIEF YOU TO THINK **VERY VERY CAREFULLY** WHERE TO
FIT YOUR ALLIGATOR "GND"

Remember that this clip is the "GND" of your scope...

So when dealing with ISOLATED networks you may
connect these points safely whit no worries about real
ground or line shorts

YOUR SAFETY IS AS GOOD AS ALWAYS.  USE PROTECTIVE GLOVES
anything above 100 may cause some panic risking hard movements.
Fix the bench gig and touch with gloves.

Good and cheap enough for anything real life
but not StarTrek  like based equip.

Paul