Upgrading to electric stabilizer jacks

First, check Lippert's wiring diagram. There should be a mini-breaker for each jack (like the one's in an A-frame) plus a fuse as I recall. Our breakers are mounted on the side of the frame I-beam next to the jack. Fuse is for short circuit protection and breaker is for overload protection. I think some manufacturers don't install both though (big cost savings??). On a retrofit, you can run new pos. wire up to the A-frame and use an in-line fuse there (weatherproof).

If you want to go a step further and get fancy, you could get rid of the metal 4x4 box in the A-frame, use a watertight PVC box and then install fuses & breakers in it along with splices, which is what I did.