What's with the oem wiring not being fused....

[loudsubz]

...close to the battery? I know from my car audio days they always suggested as close to the battery as possible when running power from the battery. I assume that was because anything on the car would be considered a ground and could short easily enough so I assume in a marina environment you don't run into this issue as a ground is only present around the engine block or if you have a ground terminal installed remotely?

I was planning on re doing some connections at the battery for ease of removal and installation and was debating between a fused distro block vs non fused to save some money.

[EarmarkMarine]

The master fusing of the helm buss and stereo equipment should be within inches of the battery or battery switch. The purpose is not for the protection of the electronics and accessories. The intention is to protect the boat and boat occupants in the event of a boating accident. For example, a shorted 4-gauge wire could catch everything surrounding the cable on fire before the cable would burn through. The close proximity of the fusing is simply to reduce the exposure and risk. So now that we know the purpose of the fusing and the correct location, we know that a fused distribution is not the way to go for the master fusing. The fusing (or breaker) needs to be close the the battery or battery switch and the stereo distribution block should be on the amplifier panel as close to the amplifiers as possible. If you want redundant fusing at the amplifiers for any reason, whether the amplifiers have no self-protection or you want to independently fuse the smaller gauge extensions from the distribution block to the amplifiers, then you can. But if the distribution block is close to the amplifiers, the extension leads are very short, then you have minimal exposure and risk to protect at this location. One purpose of a distribution block is to keep the wiring clean and simple, meaning one heavy feed running the longest distance rather than multiple smaller feeds. So placing a fused distribution block at the battery makes little sense. Rarely is a distribution block needed at the battery or switch since either the battery or switch posts will easily accommodate three terminal lugs (alternator/starter feed, helm buss, and stereo supply) and there is generally no reason for any more.

You cannot skip the fusing close to the battery regardless of your particular scheme and reasons.

If you have different reasons for a distribution block at the battery end beyond the considerations referenced above, then there is no reason not to.

David

[loudsubz]

Thanks for responding, I knew it should be fused to protect the wire from over current so I couldn't figure out why they would skip it, but looked again and saw the small breakers right beside the battery switch, so I am not scratching my head anymore why they would not fuse.

As for the distribution block, well it would replace the where the breakers are now, only I might put it right at the battery instead and have a short main feed so it has minimal exposure.

Right now all the breakers for the independent lines are all on the right wall where the battery's go so the leads are like 14 inches before they are fused so they are exposed.

Right now we have the dual battery setup and about 4 lines running to the pos terminal in addition to the stater cable, so its a pain trying to get them all on and tighten down the terminal.

[EarmarkMarine]

You can jumper a terminal lug off the input side of an existing breaker provided that the supply cable is adequate for the current demands of both circuits and both circuits are fused independently. But don't stack more than two at this junction point and make sure you use 1/4" lugs on 1/4" posts (typical of a breaker) as you need all the surface area contact possible.
Every main circuit, like the amplifiers and helm buss, should have their own fuse/breaker based on the cable size & length and the current draw.
I agree that four lugs could be one too many off the dual battery switch post. Not sure why you would have more than three. Certainly a distribution block would be used to eliminate redundant amplifier runs.

David