breaker panel plus switches?

[Han]

Hi All,

I'm in the process of doing some rewiring of our DC system, and being a novice at this kind of thing, I have a bunch of questions. The first one is about setting up our circuits.

Our current DC circuits with breakers on the panel are:

1. cabin lights (all interior lighting and fans)
2. spreader lights
3. foredeck spotlight
4. mast head tri-colour
5. running lights (this includes the deck level red and green lights as well as the steaming light and the stern light).

Our VHF, depth sounder, and three random lights are not on breakers at all.

Obviously I'd like to get all our wiring protected by breakers, and while I'm at it I'd like to reorganize the circuits a bit. What I'm thinking is;

1. port cabin lights and fans
2. stbd cabin lights and fans
3. navigation equipment (VHF, depth sounder for now, maybe GPS and SSB in the future).

After this I run into difficulty, I'd like to break up the nav lights a little (ie so the steaming light doesn't necessarily come on with red/green lights, since it is a sailboat), but we only have 6 breakers. Is it ok to wire one or two breakers for the nav lights, but then have a switch panel so I can control them individually? Does anyone have another suggestion?

Any help is much appreciated.

[DeepFrz]

Your VHF must be on it's own breaker. The SSB should be wired directly from the battery, to a breaker near the battery, to the SSB. It sounds like you need another breaker panel. Check the Blue Sea web site for wiring diagrams and technical information. You may want to consider putting the Nav Lights in a waterproof breaker panel in the cockpit near the helm so you don't have to run below to switch on the lights. That will free up space on your below decks panel for the VHF.

I would suggest you get a good marine electrical/systems book to help you.

[GordMay]

Yes.
You can install a switch panel, to separately control several sub-circuits, all protected by a single breaker/fuse. (exactly as , and for the purposes, you describe)

[hooked on water]

What is everyone's opinion on using breakers or fuses
have all fuse panels at the moment

[David M]

I dislike fuses, I will take a breaker over a fuse any day. Whatever you choose, make sure every load has some sort of overload protection. Don't you just hate the smell of melted insulation? You just know something, somewhere has gone terribly wrong...and now it is your job as skipper to sniff around and find it!

You need more breakers! You can buy them or custom make your own breaker panel out of plastic. A number of manufacturers make breaker panels. I made my own since nothing on the market matched what I needed and if you are the do-it-yourself type, it is actually pretty easy. All you need to do is make a trip to TAP plastics and half a day with the table saw, the jig saw and the drill.

You can wire a three way switch to say sailing-off-steaming or something similar so your masthead light goes off and on separate from your side and sternlight....and have a separate 360 anchor light.

The only refinement I noticed is putting your cabin fans and you cabin lights on the same circuit. Only similar things should be on the same circuit. Anything that is safety related such as the VHF, navigation lights, bilge pumps etc, absolutely need to be on their own dedicated breakers or fuses.

[Wotname]

Originally Posted by David M

I dislike fuses, I will take a breaker over a fuse any day. ......

I dislike fuses also but I can't really explain way - apart from the obvious factor that it is easier to reset a breaker than replace a fuse (and some circuit breakers are manually tripable and/or switchable)

BUT I have literally used 100's of circuit breakers and fuses professionally (12 / 24 V DC) and if they are faulty, it is amost always a circuit breaker thats gives me grief rather than a fuse - so I remain undecided.

Why do you prefer CB's?

[David M]

Originally Posted by Wotname

Why do you prefer CB's?

In my experience, circuit breakers rarely go bad.

Circuit breakers are all in the same place which saves time and eliminates the hassle of removing doors or panels or whatever in order to go looking for that inline fuse.

Fuses cost money every time you burn one up.

Breakers allow you to kill the power to the load at the source so you can work on the wiring.

Breakers make a nice on/off switch, versus finding and pulling a fuse in order to turn something on or off that may not have a switch on the device itself...such as a cabin light.

Breakers are right next to your DC panels ammeter, which means you can see the loads additional draw when turning on the load. This tells you immediately if something has shorted. How many inline fuses are right next to your ammeter?...not many.

Fuses protect all of the positive DC wiring between the source (or the bus) and the load. Fuses generally only protect the device and not the positive 12DC wiring because fuses are generally located at the load.

The only advantage to a fuse? ...they are initially cheaper than a breaker.

The only place I have fuses is for my bilge pumps and at the back of my VHF because of that infrequent breaker that can go bad. Fuses are more reliable in that sense.

BTW, I coat my fuses and fuse holders contacts in silicone grease which stops any corrosion and for some external connections subject to direct seawater spray, in TefGel. Doing this does not increase the resistance. Not doing this would potentially increase the resistance of course.

[Wotname]

OK, I agree with the comments about in-line fuses - I hadn't considered in-line fuses as I never use them - for the reasons you state.

The fuses I was thinking about are panel mounted fuses used in the same way as a CB.

And I like CB's for the same reasons that you state and I must add the percentage of bad breakers is very low (but not as low as a bad fuses), in my experience.

I do have a problem with cheap fuse holders (panel mounted) and it is very easy to buy poor quality fuse holders unless one has access to trade suppliers and a good breaker can be more water resistant than many fuse holders.

So breakers arre better just more expensive!
Thanks for you thoughts

[David M]

I use panel mounted fuses for my bilge pumps because they are reliable.

[hooked on water]

yes i am talking about panel mounted fuses also

[hooked on water]

I have also an electrician friend talking about fitting RCD units to boards
any ideas on this also, with being low voltage, this surely is overkill

[Wotname]

Originally Posted by hooked on water

I have also an electrician friend talking about fitting RCD units to boards
any ideas on this also, with being low voltage, this surely is overkill

I know I am a bit old fashioned (and maybe getting a bit old as well ) but I have never heard of 12 VDC RCD's and can't see why one would need one on a boat.

BTW, just realised why I have seen less dud fuses than dud breakers - 'cause I work mainly with breakers - percentage wise they may fail at the same rate or the fuses may even be worse - Duh .

[hooked on water]

I am going for circuit breakers
does everyone go for ready built panels or build themselves
have seen some pretty nifty ones on the net
whitworths on line mag
what has everyone else got
thanks
hooked

[Wotname]

Build myself - but that is just the way I think

[David M]

I have built my own breaker panels out of necessity because nobody had exactly what I needed. If you do it right they can look pretty darn professional.