I would have to agree with Nigel on this, lifting the earth is way safer in some cases, and not so in others, just ask anyone that has touched their probe gnd accidentally while pokin around a tv chassis at half mains. That said, what I have is my earth lead cut before the plug. I made up a lead that I bolted to my chassis gnd stud on the scope with a croc clip on it to bond to the DUT, I figure if it has be at any potential, better it's all at the same potential. No matter what I'm doing, even if I'm not using the scope, I always clip it on to the chassis of the DUT. I would recommend however, that your test bench be run from an Isolation transformer heavy enough to cope with all your test gear and any DUT you'll encounter, or envisage having on it and bond all your test gear. All the test gear I have on the bench is cross bonded, but not electrically earthed because of the Isolation transformer. Happy days...