Wiring Diagrams

[Willallison]

I'm up to that part of my studies that covers marine electricals.
Can anyone point me in the direction of some good (pref online) examples of AC & DC wiring diagrams?

[AlaskaFisherman]

blueseas.com
They have exaamples in their catalogs.

[Willallison]

Thanks - great looking catalogue and I've ordered a copy - always nice to have a hard copy, not just a pdf on the 'puter (it's www.bluesea.com by the way .. www.blueseas.com goes to the site of a very nice looking LR cruiser)
what I'm really looking for though is examples of complete wiring diagrams for boats, both power and sail. Many manufacturers seem to show each section of an installation - understandable since that's all they're trying to sell - but not the whole thing.
I can figure out how each part fits in, but what I'd like to see is how the whole schematic looks.
Also would like to see a diagram of a DC ring-main system...the next big thing...?

[AlaskaFisherman]

In the catalogue there will be complete systems.

[Willallison]

I received an email form Blue Sea Systems. Understandably - but regrettably - they no longer mail out catalogues to people overseas....

[D'ARTOIS]

You have complicated and less complicated diagrams. Would you like to have one of a megayacht or just a 30 meter one. The mega is a book, the 30 mtr might be put through the scanner. Just clarify what will suit your need and I will have a look in the archive.

[Tim B]

I would personally start from first principles... that is, one has a battery, generator, engine, AC input and battery charger. The first job is to link these up usually the generator and AC input will go into the battery charger which will connect to the battery via a main isolator switch. The location of this switch is somewhat arbitrary, and will depend on the preference of the owner/user/designer. Personally, I would probably set it up as a powerful relay controlled by an on/off key-switch. The engine then needs a start-switch which may be done in a similar fashion. This ensures that the heavy high-power cable and electronics lives by the batteries/engine room and the helm station has only light signal cable running to it. The main engine fuses then live in the engine room in the box with the relays what type they are depends on availability and preference.

Ok, now for DC power... The main feed cable must be capable of taking the current which will be drawn from the battery due to the extra apparatus. since P=IV : I=P/V : V=12 so I=P/12 ... those 25 W NAV lights take just over 2 Amps each. you should always multiply this answer by 1.5 for a safety margin (stops wire getting too hot), so it is likely that in addition to the big cables running to the engine room there will be a sizeable pair of cables running to a distribution board somewhere; possibly the helm on a motor-cruiser, or the NAV table on a yacht. This distro board may be staight-switched in low powered cases (switches will typically take about 10 Amps) or relay-switched. The second set of fuses will live on or near this distro board.

Relays are finding more use in larger motor yachts and big ships these days, especially when big loads are to be controlled, such as bow-thrusters and anchor winches. These would generally be run with the engine distro board and controlled by signal cable from the main switch-panel. The big advantage of relays is that they only need about 1/4 of an amp to switch them. This is easily supplied from a small transistor, controlled from a computer/microprocessor. It will not be long before we see full immobiliser systems installed as standard.

From there the 'non-essential' wiring is very much like house wiring. The Nav lights will all come off a single switched supply, as will the windscreen wipers etc. The interior lights may either use a couple of panel switches, or more likely individual switches either on the unit or on a 'wall'. There is nothing to prevent DC power from being wired with standard mains power cable (only 2 core is needed).

If you need a general design, drop me an e-mail with deck-plans, a side elevation, and basic layout, and I'll have a look at it.

Hope this helps,

Tim B.

Tim@MarineDesign.tk

You want the whole schematic so you can see how they tie all the different circuits together. Go to any automotive dealer and speak to the service Mgr. Ask and you will get a schematic that is the equal to any Mega Yacht. Autos are very good because they also have block, wire run, plug & socket, function and all the color codes to really make a master print reader out of you. They also have loads of notes and switch positions to trace thru. When you see the schematic you may not balk at the prices for running down intermittant problems. Some larger public libraries have a engineering section with the "Audels" books.

[Willallison]

Thanks guys -
D'artois: I'm looking more in the 30 to 60 ft range. Power and sail (though I realise most of it will be similar).

TimB: I get the way each bit is s'posed to be put together. I'd just like to see a completed schematic so I can get a better overall picture of it all. Not too sure about your use of house cabling. Where I come from these are generally a single core (strand) of wire...not recomended for boats...

[AlaskaFisherman]

Give me a fax number and I will see what I can come up with. These will all be for power boats and may be more to the commerical work boat but the electrical circuits will be good to look at.
I will have to find them for my own use soon anyway.
Have a good one.
ps: I am in and out of the office a lot so it might be a little delay it faxing it.

[Tim B]

when I said "house wiring" I was referring to the wiring patterns, not the cable itself.

Of course, if you wanted to make it as efficient as possible you could always Dijkstra's algorithm to find the shortest length of cable.

Tim B.

[cgorton]

Will,
http://www.midcoast.com/~aft/index2.html
Try that link- there are some schematics. Also check out (on that page) WireSizer, which is great little app for sizing your wires to ABYC.
Cheers,
Craig

[Willallison]

My thanks to you all - between them, I have all that I need and more. You guys are the best

Now - and I hate to push the friendship - but as a matter of interest, don't s'pose anybody's come across a schematic of a DC ring main system...

What is it and what does it do?

[AlaskaFisherman]

I lack knowledge as to what this is, but i have a electrican friend that was in the navy. More detail and we may come up with something. If we do it will be a week before I see him.