Areas of Expertise?

[Full_Monte]

I hate inline fuses. Put in a fuse block per my picture above and wiring, trouble shooting and fuse replacement is much, much easier. At 20A as F_M suggested, you won't save anything plugged into the socket, just the wire. If you want to have accessory protection, start with a 5A or a 10A and see if the spot light blows it.

That's an OK approach for most small appliances. The problem is that your fuse block has a current-carrying capacity as well, and if you exceed it, you will cook your fuse block. Let me give you an example. I just installed two Scotty electric downriggers. Each is on a 20 amp fuse, per the instruction sheet. If I raise them both simultaneously, I could be drawing as much as 40 amps. When I was looking for a fuse block at the boat store the other day, half of them were rated at 20 amps TOTAL for all fuses. I therefore hooked the downrigger wires directly to the battery with inline fuses, bypassing my fuse block. I put the inline fuses under the cover of my battery, with only the wires protruding. Not elegant, but safer than an electrical fire next to my gas tank....;(

 

[SuperD]

Siting your example, I have 4 Cannon electric downriggers, each requires a 30A circuit. I run them through the fuse block in the link below and never have a problem. The only time our downriggers pull the kind of amps to blow a fuse is when we hang a ball and if I hang all 4 balls, I won't be trying to retrieve them all at the same time. What would you say is the max amp rating of these fuse blocks?

http://www.westmarine.com/webapp/wc...=true&storeNum=5002&subdeptNum=9&classNum=295

 

[Full_Monte]

The fuse blocks in your link are rated at 100 amps. This is very high compared to the ones I saw at the boat shop. Without getting too technical, any fuse block that doesn't have a main fuse/breaker is called a sub-panel. If it has a main breaker, it is a main panel. Think of your house panel. It has a MAIN breaker that protects your panel from pulling too much current. It may also have a breaker that feeds a sub-panel....which is rated at lower current than the main breaker. The point is that each panel has a capacity that should be protected against over-current, just as each fuse in the panel protects a downrigger, lights, radio, pumps, etc. Let's say that your panel is rated at 100 amps. You could have 10 fuses/breakers that each guard a 15 amp circuit. If all the circuits were turned on at once, you could trip the main 100 amp breaker because you are drawing up to 150 amps. But in real life, we don't use all the circuits at the same time very often, so we don't trip the main. But we wouldn't want to run more than 100 amps through the panel at any time because it isn't designed to take it...that's why we use a main breaker. That's also why we need to size the wire going into the panel from the battery for the maximum current we might draw. If your fuse block doesn't have a main fuse, you should put an in-line fuse between the battery + terminal and the fuse block to be on the safe side.