You know, I work on so many different things, I often see things in one area that would be useful in another but is unheard of there.
Protecting fuses and circuitry from the environment is a big part of the electronics and electrical business, and there is lots of stuff out there to do it.
For instance there is the National Electrical Manufacturers Association, or NEMA.
Among other things, they rate electrical enclosures. They use a number system that is not all that logical.
In other words, the bigger the number, not the tougher the box. There are lots of places that explain the system.
But here is the horse's mouth so to speak.
http://www.nema.org/Products/Documents/nema-enclosure-types.pdf
However, if you want a tough box that will keep things dry and safe under the hood, do a search for NEMA4 or 4X boxes.
There are thousands of different types, shapes and sizes out there. The "X" means noncorrosive, and more costly.
In other words, fiberglass, special plastic, or stainless steel.
None of the boxes are all that cheap, but they will get the job done, and are off the shelf items.
Many even have clear lids or windows so you can see problems without opening the door.
If you put a little extra money in the box, then the fuse panels do not have to be special since they will never see water.
If you want to do a redesign of the system to improve it, consider DIN rail.
I'm not going to tell what that means, its German, and I don't remember it right off hand.
But, its a standardized mounting system that bolts to a plate inside a NEMA box, and then about anything you can imagine snaps to it.
Fuse holders, circuit breakers, relays, timers, all kinds of stuff.
Lots of places that sell that stuff too.
As for getting the wires in and out, there are bulkhead fittings that are waterproof where they go in the box, and have O rings or seals that squeeze down on the wire when a nut is tightened to make it waterproof also.
I would not try any of this for a simple minor repair or slight redesign, but if you were redoing a setup from scratch, its something to think about.
Although the box might be an idea by its self.
I had to design and build some control boxes for a company a year or so ago. Used NEMA4X because it was going to be in a dirty environment.
One box basically just had two timers and a circuit breaker mounted on DIN rail.
That pic lets you see the rail setup.
The second one, got more complicated.
The wires you see going off to the side went to two switches mounted in the door, and the grey blocks with the orange pieces are terminal blocks. In their simplist form, they have screw connectors on each side that you use to hook up wires.
Those type just pass the power through from one side to the other.
The orange pieces jumper the blocks together so that they share the same circuit if desired.
The terminal blocks get very complicated if you want with multiple circuits.
They also sell terminal blocks with swing-out fuse holders that break the circuit when you swing out the arm with the fuse in it.
Plus, you can get them with an LED that lights up when the fuse is blown if there is still a load on the circuit.
Here are a couple of pics showing what the box looks like inside with DIN rail.
Since your system would not need the depth I needed for the timers, your box would be a lot different and smaller.
Getting old sucks. 
but until then I am honing my solder skills and seeing what works and what doesn't.
