Electrical Question- Switches yes or Not

[JC]

Hi There. Happy thangsgiving!!!! I am in a different country but lived for a while in Baton Rouge, Louisiana so I can remember the good ol smell of turkey, sweet potato pie, and all the other goodies.... Lucky you....

I have a question regarding an installation...

I am in the process of having an electrician organize all cables from the distribution panel of the bridge to all instruments (there is a big mess there from previous owner)....

He recomends after the distribution panel I add switch boxes with fuses to so that each instrument can be turned on and protected individually...

currently what we do is every morning we are going fishing we turn all the instruments on at the distribution panel... Is this recomended practice or not??


He says DC is more of a fire hazard than AC and that if something short circuits that it can catch on fire really quickly....

I dont know too much about electricity so yout inputs are welcome...

Thanks,

JC

[JP Dalik]

The general rule of thumb is "If your not sure put a fuse in it" That being said I see no reason not fuse the gauges as a pack and have port and starboard gauge fuses.
Each piece of electronic equipment should be fused individually. Then it can go to a main breaker which is protected as well.
Nav lights Anchor lights Cockpit lights... Yep each should be isolated and protected with a fuse regardless. The closer to the power source the fuse is, the safer the whole circuit is.

[IRGuy]

I am in the process of redoing almost all systems in my previously poorly maintained 1983 B33. The 12 volt electrical system is almost completed. I used the following criteria...

Breakers such as in the main panel are often used as "on/off" switches, but in fact a breaker is there to protect the circuit from overload, not as an on/off device. Usually your breaker panel has fewer circuit breakers than you have devices, so breakers usually feed a circuit to which several devices are connected. These breakers therefore have to be large enough to handle the load of several devices operating at any one time, and therefore offer no protection for devices with small electrical loads..

In the case of my project I had one breaker in the main panel labeled "Electronics".. this fed power to the flybridge. When I traced all the items connected to this circuit I found some engine instruments, the fuel gauge, a spotlight, the horn, a CD player, all the nav instruments, all the nav lights and the anchor light, a bilge pump, and a bilge high water alarm all connected to this one breaker. I renamed the original "Electronics" breaker "Flybridge Power #1, and added a second circuit to the flybridge named "Flybridge Power #2". Number 1 now feeds through a local flybridge switch/fuse panel and terminal strip all navigation instruments and the engine instruments. Number 2 feeds through a second local flybridge switch/fuse panel and set of terminal strips all the other items such as the horn, spotlight, nav and anchor lights, etc. All bilge pumps and alarms were rewired to NOT be breaker protected, but each has it's own inline fuse, and each is fed directly from one of my 3 batteries (one each for each engine and a house/generator starting battery). You do not want any on/off breakers or switches in a bilge pump or alarm circuit except, as I have, if you want to have the ability to monitor your pumps from a dedicated bilge pump panel. (This has a switch for each pump which has an on/off/auto mode as well as a light to indicate when each pump is running, and I have made a hinged clear cover for the panel which makes it difficult to accidentally turn off power to any pump or alarm.) The criteria here is that bilge pumps should be powered directly from the source, with as few as possible connections or devices which could either fail or be turned off accidentally.

Each other device on the boat should have a fuse or breaker protecting it, since the large breaker for the circuit is too large to protect individual items. I therefore have local inline fuses and local switches in some circuits (such as my holding tank discharge pump and my fresh water pump) protecting individual devices, and in the case of the cabin lights I use the circuit breaker as protection for that system, and individual switches on each light.

There will probably be some comments posted here which take issue with some of my positions, but this is the way I decided to do things after reading a lot and asking a lot of questions.