Question
My newly finished waterfall is fed from a lower-end reservoir where I've a small 110v pump. Having NO switch, just a male end. I do have an outside receptacle on the house coming from a GFI breaker. I've just an extension cord at the moment but want to have some sort of SAFE disconnect close by so there's no need to walk all the way to up-plug it. So, can I add a switch to this GFI line running between the outlet and the pump without it tripping-do you think?

Answer
Charlie,

Probably...   But it depends on... how many amps your pump draws.  How far the actual distance is.  What size extension cord you use.  How old your GFI is.  Anyway, you are probably OK.  Simply adding a switch shouldn't add any extra amperage draw.

Good Luck,

John