Wiring

[benri]

Does anyone have an idea what type/quality and gauge of wire I should use on the boat from the battery to a switch panel? Is it normal wire or specific marine wire? And what thickness/gauge?
From the swith panel I shall be supplying:
1. GPS/Fishfinder
2. VHF
3. NMEA Network power
4. Horn

[EmicMalta]

nothing special. There you wouldn t be using so much current

[bigboy]

We usually use normal wire. Try using a good thick wire though in the range of 3-4mm thickness as it is important not to get the wire to overheat.

What you are saying is having a main from the batteries up to a panel where you will be connecting the accessories.

[shanook]

Benri whatever u do dont use normal wire. it should be multi strand flexible wire, thats the only one good for marine use. Better if you buy the coated one, Ramio should give u more information......What is the distance from the battery to the panel

[benri]

Thanks guys. The distance between the battery and panel will be approx. 2-2.5 meters. Any idea from where you can buy this type of wire Shanook please or is it normally available from ironmongers?

[The_Gaffer]

Benri, what you need is marine grade multi stranded wire.  Calculate the total load in AMPS on your switch panel, i.e. GPS/FF+NMEA+VHF+Horn.  Now depending on the distance from the switch panel to the batteries determines the wire gauge (thickness in strands).  I suggest you pop down to Gzira at Fabian's outlet armed with this information, i.e. tatal load plus distance and they will be able to work out the best solution in terms of wire gauge.

[fishfinder]

Benri,

if you really want a very good marine wire that will serve you a lot without corrosion i suggest you buy oxygen free wire. Currently I'm changing all my wiring installation as the my first installation was 4 years ago and all cables corroded. You can buy these cables from The strand in front of Flamingo and if you need heavy gauge you can buy them from TellyMike Qormi 21440333. when you crimp try to use gold plated and use heat shrink wrap at the ends to elimate air. once ready cover the terminals with transperant grease or vaselina and you will have a 100% marine proof cable which will last you for a very very long time.

by the way these wires are a little bit more expensive but really worth it.

[skip]

Bryan,

Ideally you go:

Battery/Batteries -> Battery Switch -> Bus Bar

Bus Bar then feeds your existing factory switch panel, any additional switches/switch panels you might buy and technically your VHF should be wired directly to the battery bypassing the switch. In my case I chose not to do that and put it on to the bus bar.

Battery cable should be a) Marine Grade Type 3 stranded b) tinned copper stranding c) Premium vinyl insulation. Terminated with good heavy duty lugs tinned copper etc and heat shrink as suggested above.

Your primary wire should be the same, Type 3 stranded tinned copper marine UL.

I'd also advise using waterproof connectors (rings, snaps, sliders etc) someone def does get them locally and I believe they also already have heat shrink on them.

The problem that Charlot encountered is due to the harsh marine environment, ordinary automotive-type wire can suffer a loss of conductivity after a few months in the marine environment, caused by corrosion and/or vibration. Even the stuff they use for high end stereo installs doesn't really cut in as the environment is very different.

In terms of guage as Gaffer and others have pointed out.

[benri]

thanks all for your input - I've become a primary electrician in a matter of a day :-)
@Skip - Do you use a busbar for the positive too? I thought that you should only wire the negative to a busbar and the positive direct from the battery switch.

[shanook]

the positive bar is not called a busbar (sorry dont know its name) it looks like a busbar but with slider fuses for each outlet. This is better than direct as u have each individual item covered by a fuse.

had a look on internet and closest name is Breaker Block

[The_Gaffer]

The appropriate name for it would be your DC distribution panel (box).  You can have a system whereby each circuit is wired to a fuse, or a more modern one to MCB's (miniture circuit breakers).  Blue Sea Systems make great distribution panels with various outputs, ranging from 3 to 30 outputs, all pre wired and having various fuse ratings on their MCB's.  I'm posting a link for your convinience to gain a better understanding of distribution panels, how they work, and various prices in US$.   This link will take you to westmarine.com, a great place to buy marine realted gear and stuff, and featured here on the forum.
http://www.westmarine.com/webapp/wcs/stores/servlet/SiteSearchView?dispName=ELECTRICAL&jspStoreDir=wm51&catalogId=10001&Ntt=Meters+%26+Distribution&N=377+710+1630&langId=-1&page=CategoryDisplayLevel1&omniTag=Category%3aMeters+%26+Distribution&storeId=10001

[skip]

I used this panel to complement the existing factory one http://www.westmarine.com/webapp/wcs/stores/servlet/producte/10001/-1/10001/223075/377%20710%201630/0/Meters%20/Primary%20Search/mode%20matchallpartial/10/0?N=377%20710%201630&Ne=0&Ntt=Meters%20&Ntx=mode%20matchallpartial&page=CategoryDisplayLevel1&isLTokenURL=true&storeNum=5002&subdeptNum=9&classNum=348

And this dualbus bar:

http://www.westmarine.com/webapp/wcs/stores/servlet/producte/10001/-1/10001/80138/377%20710%201630/0/Meters%20/Primary%20Search/mode%20matchallpartial/10/0?N=377%20710%201630&Ne=0&Ntt=Meters%20&Ntx=mode%20matchallpartial&page=CategoryDisplayLevel1&isLTokenURL=true&storeNum=5002&subdeptNum=9&classNum=753

As gaffer pointed out the DC distribution panel/switch boxes have their own fuses so you don't need them on the bus bar, plus more to go wrong. Any item being connected directly to the bus bar should either have its own inline fuse or if you want you can connect it to a fused box as Shanook is mentioning if you want additional protection or don't have inline.

[shanook]

Agreed with all above if the dc distribution panel is to be mounted on console that is open to weather than you need the dc distr. Panel. But if u are going to place the breaker block inside the console that is sheltered for weather than it a cheaper option to the distribution panel. Ur money, ur choice,

[ramio]

Hi Benri, sorry I didn't post earlier. If you have an open boat, and the electric panel is going to be subject to salty humidity, even if not direct spray, avoid complicated panels with MCB type breakers. At sea experience showed me simple and safe.
Starting with wire, although it's a short run, go for a 6mm multi strand cable. Use marine grade which is tinned, will last a lot longer. The heavier cable will heat less, and be safe if you install some other small things in the future.
I suggest you go from battery, to main switch to busbar with both +ve, and -ve. Go to electrical shops and ask for the basbars they use in domestic /industrial distribution boxes. Its basically a brass strip with holes and threaded screws. Just scew these onto a non conductive material such as fiberglas panel or a piece of painted marine plywood. Outputs can be wired directly from it either through an inline fuse holder (which is cheap and easyly replaced) or using one of the readymade multiple fuse holders.
Re terminations, I found best to use the solderd type crimps. You get a good soldered joint which lasts for a good time. I prefere no insulation, but if you want, they should slide free on and off so you can inspect and clean easy.
When installation is ready, buy a tin of "All defend" fom the MaFra range of car products, and give a good spray over all the terminations. This will serve to protect from corrosion and water. Wipe any drips a couple of days after using a clot with some light penetrating oil spray, or parafin. My wiring terminations have been done this way and have lasted 12 years and are stil solderable. The only things that failed were the switches. Condensation creeps inside where you cannot protect, and the contacts fail.
Out at sea, you need reliable equipment, which can be worked on easyly in emergency.