Thoughts on the 'need' factor of a main line surge protector

rbpru wrote:
My question is how many joules are needed?

I suspect if lightning strikes near enough to put an impulse on the line, your surge is toast with the rest of your gear.

Likely never enough joules for lightning but might be OK for smaller electrical transients.

However, crossed wiring is a problem I have run into.

I've always carried a 50/30 adapter, 30/20 adapter and a common household tester which does the job. Not to likely a miswired pedestal when initially tested will change later...