Which SR Blue or black Fuse

I have two Blue Fuses to go into the IEC input on two mono block amps (one fuse per amp). One IEC is reversed (vs. the other).

What is the first attempt probability of getting Fuse orientation correct (across both amps)? Thanks.

50%. It’s always 50% since the fuses are not marked for direction. That’s my final answer.

Thanks, Geoff. Even across two amps? 

For each fuse the odds are 50% of putting it in the right way. The odds of putting more than one fuse in simultaneously the right way is less than 50%. With two fuses, one fuse should be evaluated first. When you decide which way is best, then evaluate the second fuse. Otherwise, it can get too complicated. Even worse for three or more fuses. If a little unsure about the first fuse direction when listening take a guess then move to second fuse. Repeat. It should more obvious the second time around.