Boat rewire help

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BoatBuoy

Rear Admiral
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May 29, 2004
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I’m in the planning stage to rewire my boat soon and I’d like to run the plan by you folks and let you shoot holes in it. <br /><br />The boat is aluminum (runabout). Because of this, I want to fuse it as close to the battery as possible. I really don’t have a place to mount a fuse panel so I’m planning on using inline fuses. <br /><br />I’m currently planning on 3 circuits using 14 ga. wire - one circuit for the spotlights, one for the horns, and one for the cigarette lighter. The bow and stern lights are very small and draw very little current. <br /><br />I would like opinions as to whether to run a 4th circuit for them (bow and stern lights) or could I tie them into one of the other 3. Also, for the fuse size, how much capacity should it be rated above the calculated load. Thanks in advance for any response, suggestions, criticisms, etc.<br /><br />Electrical complement:<br />2 trumpet horns @ 3.5 amp each<br />2 spotlights. Based on replacement bulbs of same size, I would guess 4 amps each.<br />1 cigarette lighter (accessory outlet to be politically correct)<br />1 each bow and stern lights of minimal wattage, I’m not sure how much.
 
L

llfish

Senior Chief Petty Officer
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May 2, 2003
Messages
695
Re: Boat rewire help

I recently rewired my aluminum boat. One main lead from the battery to console fuse panel. From there I ran circuits to lights (2), horn, fish finder,air-rater and bilge pump. Bought an assortment of fuses and started with the smallest fuse and worked my way up until they stooped blowing. Only did that for the two items that I had no idea the amps they needed. Then added up the sum total of all fuses and placed an in-line fuse at the battery. Figured that I would never have all electrical devices running at one time.<br /><br />The main feed runs through a rubber tube.
 
C

crab bait

Captain
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Feb 5, 2002
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3,831
Re: Boat rewire help

don't need a 4th circut unless you want to turn off & on by the fuse.. if not,, put it on the horn circut.. ( rarely used )..<br /><br />i'd put 10 amp fuses in everything..no need to get fancy.. no sensitive electronics.. an that way,, you only havta carry ( an lose & find ) one kind..
 
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18rabbit

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Re: Boat rewire help

I haven't had my morning coffee yet but I like Crab Bait's advice. You can get all fancy about it and try to match fuses to accessories but I don’t see a need for it. I don’t think a trumpet horn or light bulbs are considered sensitive electronics. :) <br /><br />The only thing that caught my attention was your politically correct cigar lighter. I would wire and fuse that critter for it’s rated amps. It might be as high as 15amps. On the other hand, if yuo fused it for 10amps, can't hurt either, if it is rated for 10amps or more. Would be nice to use the same fuse size for everything.
 
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Paul Moir

Admiral
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Nov 5, 2002
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Re: Boat rewire help

I agree with crab bait, combine the horns and the bow&stern lights. Bow & stern lights typically are under 10W each, so figure on 1 amp for each. It's good to go with a wide saftey margin on them.<br /><br />I would set up the 2 spotlight circuit for 15amps though if you run both at the same time. Typically they have 55W bulbs in them (4.5 amps) and 9 amps total is too close to the fuse blowing 10. It's a good idea to normally draw no more than 80% of what the fuse is rated for. So no more than 8 planned amps on a 10 amp fuse. This will help with shortened fuse life and nuisense blown fuses.<br /><br />If the cigar lighter is a ways from the battery, you may want to wire it with #12. This would be a certainty if you wanted to run a 150W inverter through it occasionally since you'd want to keep the voltage drop to a minimum for it. <br />The spot light will put up with a much larger voltage drop, so you can use a lighter guage wire for longer distances. If you wanted to limit the drop to say 10%, you could use up to 40' of your #14. So no problem there.
 
T

ThomWV

Senior Chief Petty Officer
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Dec 19, 2003
Messages
701
Re: Boat rewire help

I think you all are missing a mighty important point. Everything here is backwards.<br /><br />Everyone acts as if the actual Boat wireing, which is the navigation lights and any power plant as well as controls, was somehow of less importance than the accessory wireing, which are the spotlights and accessory circuit. Here we have grown men saying sure, go ahead and tie your navigation lights, which are safety equipment, into anything thats handy whle going into deep rational thought about amp draws and wire sizes for all that other junk. Your lights are SAFETY equipment, at least give them the dignity of their own circuit.<br /><br />As for the in-line fuses, I guess they have their place but I absolutly hate them. I will not install one on anything but a bilge pump line and wouldn't put one there if there was any practicle way to avoid it. Find yourself a small plastic box (use Tupperware if you have to) and screw it onto the inside of your transom. Mount one of those inexpensive fuse panels in it (Blue Seas makes a zillion different sizes and models, some very small) inside of it and put its lid back on after you're done to protect it from the elements. It will be infinitly better than a handful of those in-line-mistakes.<br /><br />Thom
 
Triton II

Triton II

Commander
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Nov 23, 2004
Messages
2,479
Re: Boat rewire help

Well said ThomWV... it's law here to have a separate circuit for nav lights in commercial craft, and what's good enough for them is good enough for me.
 
1

18rabbit

Captain
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Nov 14, 2003
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3,202
Re: Boat rewire help

Don’t use Tupperware to enclose any active electrical. If anything goes wrong with the wires going into or out of that plastic box, or if anything goes wrong inside it, Tupperware becomes kindling. The suggestion of a panel is a good one but not necessary. There is nothing wrong with fuses when properly installed. An enclosure and breakers are going to add significantly to the cost. If you end up going that direction, look on Ebay for a fiberglass NEMA 4X enclosure (waterproof and corrosion proof) and put your stuff in it, as would be appropriate. There is a reason why there are standards and regulations in place concerning electrical enclosures. Those reason don’t go away when you get on a boat.<br /><br />Fwiw, boat electrical is not a ‘do-anything-you can-get-away-with’ procedure. You need to adhere to the NEC (Nat’l Electrical Code) and the USCG regs (Aussies exempted :) ), not that there is an electrical inspection of your work or that anyone will ever check. Following the guidelines of the ABYC is also a good idea. You won’t find Tupperware listed as an approved enclosure for anything electrical with any of those organizations.
 
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Peter J Fraser

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Jun 22, 2003
Messages
598
Re: Boat rewire help

I would use (and have done so) an IP rated electrical box from an industrial electrical supply co. These are water proof with a screwed down o'ringed lid and use bushings (or can be sealed with RTV if you wish) to pass the cables through the walls. You may even be able to buy one with a clear lid so you can see the goodies inside.<br />It wont matter too much then where you place this.<br />Regards :) <br />Peter
 
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18rabbit

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Nov 14, 2003
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Re: Boat rewire help

Peter - a NEMA 4X enclosure is roughly the same as an IP 66 enclosure. Just different standards orgs. I think IP is international and NEMA is a US standard. We like to think we invented everything. :)
 
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Peter J Fraser

Chief Petty Officer
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Jun 22, 2003
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Re: Boat rewire help

18rabbit,<br />Thanks for that, I understand where you are coming from on those standards. <br />I used IP as that is what is widely used here but your own domestic standards will be able to cross ref to any other standards in use anywhere.<br />I dont have the actual details to hand but I think that IP66 is splash water proof, IP67 is immersion proof.<br />Equivalant to '65 is probably sufficient in any case.<br />No matter which is used the important thing is that all the components are out of harms way.<br /><br />Regards<br /><br />Peter
 
rwidman

rwidman

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May 27, 2004
Messages
1,396
Re: Boat rewire help

Get this book and read it:<br /><br />
0071343261.jpg.jpg
<br /><br />Powerboater's Guide to Electrical Systems: Maintenace, Troubleshooting, and Improvements<br />by Edwin R. Sherman<br /><br />It's about $16.00 at amazon.com. I've also seen it at marine centers. I have a copy and it will tell you what you need to know to do what you want to do in a safe and workmanlike manner.<br /><br />I second the idea of running a large (probably #10) wire (fused within seven inches of the battery) to the console and installing a fuse block in that location to connect to lights, horn, etc.<br /><br />Fuses should be sized to protect the gauge of wire used, there are tables for this in the book.<br /><br />And get all your materials from a marine store or the marine section of an outdoor store. No automotive or residential components, no tupperware, etc.
 
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18rabbit

Captain
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Nov 14, 2003
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Re: Boat rewire help

Yup! That would be the book I keep telling folks to get. It is an excellent one to start with.
 
S

Sea Six

Petty Officer 2nd Class
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Nov 7, 2004
Messages
191
Re: Boat rewire help

So, are you going to crimp your connectors, and solder and shrink wrap? ;)
 
1

18rabbit

Captain
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Re: Boat rewire help

If properly crimped, soldering is not necessary. This is fun!!!<br /> :D :D :D
 
Realgun

Realgun

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Jul 31, 2003
Messages
2,484
Re: Boat rewire help

18 I totally agree with you. Its in the stardards that you do not need to solder. So I will not. However, I got a really good double ratchet crimper. It does insulated, non-insulated and O.E.M. Works very well. And with the other 6 replacement jaws lotsa other things too.<br /><br />Only cavaet is I will shrink wrap all connections.<br />I got the book Rwidman.<br /><br />1. Ok do it by the book/rules<br />2. Wire it correctly the first time and use the propper fuse.<br />3. Good luck but I will not ride with you unless you get rid if the cigar lighter.<br /><br /><br />.
 
C

coby-5

Seaman Apprentice
Joined
Dec 12, 2004
Messages
43
Re: Boat rewire help

i did a rewire on an old bass tracker and did the tupperware screwed to the inside ( waterproof)<br />2 years no problems ,then for like 20 bucks i found a marine fuse panel that was perfect....and enclosed waterproof,<br />i say shop the web and you should find what you're looking for,<br />then there's always the junkyard...great for 12 volt systems !!!
 
B

BoatBuoy

Rear Admiral
Joined
May 29, 2004
Messages
4,856
Re: Boat rewire help

Well, I know the anxiety level is at fever-pitch awaiting info on my rewire job. So here's what I did. I installed a 30 amp fuse in an inline fuseholder and connected directly to + on battery. It goes to a Blue Sea fuse block about a foot away (I found a place for it) using 12 ga. <br /><br />I have one 16 ga. circuit for the running lights, one for the 2 spotlights, and one for the horns. I have a 14 ga. circuit for the accessory outlet. All circuits have their own ground wire returning to the neg. bus bar. All circuits are 15 amp, but I will adjust as necessary.<br /><br />All terminal ends are crimped, joints/splices are soldered and shrink wrapped.<br /><br />Thanks to all for advice.
 
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