Plez refer to your post below: garden power supply. (Really, there's no need to double-post. You can fairly assume that either 1) no one has seen your 1st post, or 2) folks HAVE seen it and don't have an answer at this time.
As far as fuses, the Breaker in the Breaker Panel is your 'fuse' should you have a problem. And regarding your UNDERWATER lights, be sure the wires and the bulbs and the fixture are RATED for that use.