Hello all,

For Fathers Day I treated myself to a neat little boat.  A 16' Glastron V Hull with a 40 horse Evinrude. The motor runs great. Anyway, the carpet is in need of replacing and the wiring is a mess. I want to clean it all up and add a new panel of switches and make a clean wire harness while I have it all taken apart. I want to add a fuse block in, as well as a master cut off switch.

I understand that I can run one 12v wire from the battery and into a fuse block and have several (i.e. 6) hot wires leaving the fuse box. Where I get confused is how to put the switch between the accessory and the fuse block. Would I use a 3 prong switch and have one hot coming in, with another going out and one ground or? I've never been that great with electrical stuff but I know my way around a tool box. Help me out please.

Thanks!

TD

Hot wire to fuse box. Hot wire from fuse box to switch. Hot wire from switch to accessory. Negative wire from accessory to ground.

Just like a car, only you can't just put a hole in the thing for a ground usually.

Switch should just have two wires, it does not need a ground wire.

Close, you forgot the master switch.  Battery>master switch> fuse panel>switch for accessory> accessory> ground> multi ground block> large wire back to battery.  Use large guage on your main runs and high draw items, starter, subwofer amp etc and small guage for guages/marker lights.  Solder and heat shrink your terminations to keep everthing nice and tidy and to prevent water fouling.

Edit 30JUN15: Looks like I needed to flesh this out some more, what everybody else said that mirrors what I said and added to it is correct. Crimp and solder on multi strand with heat shrink is the way to go and is .mil spec or at least the vessels I have worked on. The poster that whipped the wire and soldered it knows his stuff and thats "the proper way" to do a joint mechanicaly with solder but you won't be likely to need such a splice on a 16' punt.   Tin then wire crimp, solder and shrink and it should last until your childeren take over the helm.  Fair winds and following seas capitain and I hope you have good stringers and deck under that carpet.  Also get new batteries, the ones in your camera suck!

The only time your switches will need a ground is if they are lighted.

also, NEVER solder on a boat or use wirenuts.
Use crimped terminal connectors.
Invest in a GOOD crimper.
Always use AWG marine wire sized correctly.  Wire is stranded, never solid. The fuse or circuit breaker must be sized to the WIRE not the device it is powering.

Why no solder?

About to redo a sailboat and was planning solder with heat shrink to get rid of all the wire nuts last owner used.

From a well respected marine electrician:


http://forums.catalina.sailboatowners.com/printthread.php?t=158823&pp=20&page=2

How I tend to solder when splicing, never had a failure:



From: http://makezine.com/2012/02/28/how-to-splice-wire-to-nasa-standards/

And then get shrink tube with gel inside to make a better seal.
The shrink length on each end of the splice should be about the length of the splice.

Two plies of heat shrink tubing restores the double insulation.  Allow plenty of overlap of the heat shrink over the original insulation and the second layer should overlap the first.

Make sure there are no sharp pokey ends from clipping or soldering that might (over time) poke thru the insulation.

Why go through all the trouble of soldering and using heat shrink when a simple crimp is much faster and more effective?

Crimps and water are a bad combination.

How is a heat-shrink connection any worse than a soldered connection w/ heat shrink?

Solder forms a gas tight metallic seal and greatly limits any possibility of electrolytic corrosion.
Crimp connectors when correctly chosen and applied create small gas tight connections between the metals but are still vulnerable to electrolytic corrosion.
Gaskets and seals are used to limit moisture intrusion into crimp connectors.

Gell coated shrink tubing makes a very moisture resistant seal under the tough outer jacket of the shrink tube.
Making the area along the wire longer means it takes more time for moisture infiltration to reach the joint.

there is a big variety of crimp style connectors or terminals from basic insulated to non-insulated to heat shrink insulated ones, properly crimped they do offer a good connection the problem is corrosion at the connection cause they are not usually sealed from water or other elements even with heat shrink it may not be completely sealed unless you apply some silicone over the crimp or solder joint slide the hear shrink over it then shrink it for a water tight seal so using the non insulated type with some heat shrink tubing does allow you to do this and I don't really see this connection ever going bad.

Brickeye knows quite a bit about electrical, but I do feel his soldering is overkill, and quite honestly, too difficult for a beginner. I'm a computer engineer that designs embedded systems for vehicles for a living. Soldering is good, but it's not something you do correctly on your first try.

Anyways, the most common connection method for boats is a crimp connector with adhesive lined heat shrink tubing. This creates a watertight seal around the connection. However, you still need the proper tools to do it correctly.

First, we need to know if you're running a single battery, or dual batteries. And if you're running dual batteries, is one for the starter and one for the house loads, or are they simply in parallel. We also need to know if you'll have a trolling motor and accompanying battery bank or not.

As for your wiring, you'll need heavy gauge cable (the gauge depends on the round trip distance, and the current you expect the cable to conduct) from your engine ground lug to the ground lug on your battery. Then more heavy gauge wire from the positive battery lug to the battery switch.  Then from your battery switch, you'll run cable to your fuse block. Then from the fuse block, each terminal will run to one accessory or switch. The switch goes on the positive wire going to an accessory and switches the positive wire (no ground wire to a switch, unless it is a lighted switch and requires it for the light). Then a wire from the accessory back to the ground bus on the fuse block. Finally, a return wire from the fuse block to the battery ground lug.

As for tools, there are some that you'll need: Portable Soldering/Hot Air Tool, Wire Strippers, Ratcheting Crimp Tool, and Cable Tie Gun

Materials will include: Battery Switch (which one depends on your setup), Fuse Block, Cable Ties, Cable Tie Mounts (or Cable Ties w/ Mounts ro Sticky Cable Tie Mounts), Battery Cables (gauge depends on length and current), Tinned Stranded Copper Wire (guage depends on length and current, color depends on use), Adhesive Lined Heat Shrink Crimp Connectors (ring terminals for fuse block, butter terminals to connect 2 wires), and Adhesive Lined Heat Shrink.

That should get you going pretty well. If you have more questions, feel free to post back.

Crimp stats showing advantages in high vibration environments.
It does not create as large a rigid area as solder with teh slight added mass if solder.

Vibration 'works' the joint to keep a solid connection.
It is NOT as effective on solid wire though.
Stranded and crimps do very well.
Solid and crimps not nearly as well, especially at lower voltages.

The 'difficulty' of solder is grossly overstated.
Use rosins flux, use enough iron (large enough is just as important as hot enough), done.

In very high reliability crimping to solid wire is not allowed.
You solder splice stranded and then feed that into a crimp.

High gold crimp sleeves (thick 24 K plating over nickel on copper) are very reliable on lead-tin (AKA 'tinned') stranded wire.
Think MIL circular techniques.

Boats are vibration-prone environments due to hitting waves at speed and constant high RPMs on the engines.. There shouldn't be solid wire on a boat. All wire on a boat should be tinned stranded wire.