I'd like to ask OMNI a question (if he's still alive). He wrote his answer in 2007 and I'm asking in 2021. Anyway Omni, you recommend using a GFCI for safety. Then, you also recommend having a Variac and an isolation transformer. I understand having a Variac. When powering up an unknown condition piece of electronics like an old Tektronix oscilloscope it would be best to slowly raise the input voltage slowly in case there was a bad short in the scope. But I've been reading pros and cons about using an isolation transformer especially if the device under test and the test equipment are al