# Wiring Question: proper gauge selection and ABYC colors??



## azekologi (Jun 6, 2010)

Question for all the sparkys or sparky juniors out there…

I’m upgrading from my decrepit battery-powered lights navigation lights to wired navigation lights (see thread https://www.tinboats.net/forum/viewtopic.php?f=5&t=13952 for more info).

In a nutshell, I’ll be running the nav light wiring through the port side gunwale from bow to stern (12’), double back outside the gunwale from the stern to the rear seat (2’), where it will run to a switched panel (exact length TBD, ~2’-4’). Depending on where I place the switch panel, the length of the circuit (round trip) will be 32’-36’ (using 16’ to 18’ of wire).

The bi-colored bow light has a single 10W, 12V bulb. The packaging doesn’t list the amp draw; however similar lights list a draw of 0.62A. I’d guess it would be safe to say that it draws less than 1A? There are two short black leads coming off of the light, one wire has no writing, the other has this; “AWM 1015 22AWG VW-1 105°C 600V E77981 Wonderful CSA AWM”. I’m not sure what all of that means, but I infer that it’s 22 gauge wire (“22AWG”).

From what I’ve read so far, using low-consumption accessories (lights, blowers, electronics and panel board feeds), I should calculate gauge based on a 3% voltage drop. 

I have a fair amount of room in the 1-1.25” diameter gunwales, but there are a few screws along the length of the gunwales which I will need to fish the wire past, so I do see some advantage going with the smallest gauge safely possible. Given a 3% drop, the 1A (0.62A) draw, and a round trip circuit length of 32’-36’ feet, I calculate that I need either 18 or 20 gauge wires, possibly 22 gauge as the draw is so minimal. 

*Does this sound correct? Should I match the leads coming off the lights and go with 22 gauge wires? Can I mix the gauges? What do you suggest as the best gauge for the job? (I’m 99.9% positive that I won’t attach anything else to this electrical circuit). *

The second question I had was about using the American Boat and Yacht Council (ABYC) color standards for marine wiring of boat accessories. According to the ABYC, RED is used as a DC Positive Conductor / Positive Mains, BLACK or YELLOW are used for DC Negative Conductor / Negative Mains, and GRAY is used for Navigation Lights.

*Should I use these? Does it really matter that much? What would YOU do?*

My local boat supply store, West Marine, sells Ancor brand 18-2 red/yellow “safety wire” or 18-2 red/black duplex for $0.96/ft, or 20-2 red/black duplex for $0.75/ft. Both conductors are individually insulated (either red/yellow or red/black – no gray option that I found), in a white jacket, and seem to be marine grade (some of the pictures show the white jacket stamped with "Ancor Marine Grade", others do not- probably just the pics though). I’m sure with the power of the internet I could find other options. :roll: 

I plan to solder the connections and use 4”-6” of heat shrink wrap over each connection. As I won’t be immediately putting in a switch panel, I’ll zip tie up the extra length of wire and use clips to connect the wires directly to the battery as needed. *I don't need a fuse or anything, do I?* I’ll still be running my battery-operated 360° white anchor light until the mod progresses to the switch panel stage.

Anyway, thanks in advance for the help/advice! Cheers! :beer:


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## FishingCop (Jun 6, 2010)

You'd probably be alright with 22, but, if it we me, I'd run 18 or 20, just to be on the safe side. I would also buy it at a hardware, home depot type place where it is probably cheaper than at the marine store..... I would also put in an in-line fuse - also to be safe....


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## azekologi (Jun 6, 2010)

FishingCop said:


> You'd probably be alright with 22, but, if it we me, I'd run 18 or 20, just to be on the safe side. I would also buy it at a hardware, home depot type place where it is probably cheaper than at the marine store..... I would also put in an in-line fuse - also to be safe....



Does the average local hardware store or Home Depot sell marine grade wiring? Maybe I'm wrong, but I'd wager that they don't. I guess this leads to: "*Do I NEED marine grade wiring?*" 

I know that the individually tinned copper strands in marine grade wiring (vs. non-marine) makes a difference in saltwater applications, but does it really make any difference at all in freshwater applications? :-k 

What type/rating of in-line fuse would be appropriate?


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## bassboy1 (Jun 6, 2010)

I would likely go with 20, but I am sure the 22 would be fine. On an 18 ft. run, at .62 amps, you are at 3.09% loss. Cut that down to 17 ft, and you are now at 2.92%, which is a-okay. 

I don't give a rats hind end what colors to use. On all my boats, I use red and black. 

A fuse wouldn't hurt, but I wouldn't freak out about installing one on a light. On a sonar, or something expensive, it would be foolish not to, but for a light, it is less of an issue. It still could be a fire hazard, but if you install everything correctly, the risk for that is minimal at most. If something did go wrong chances are the light would be toast, and not much else.


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## FishingCop (Jun 6, 2010)

azekologi said:


> FishingCop said:
> 
> 
> > You'd probably be alright with 22, but, if it we me, I'd run 18 or 20, just to be on the safe side. I would also buy it at a hardware, home depot type place where it is probably cheaper than at the marine store..... I would also put in an in-line fuse - also to be safe....
> ...




Okay, you're over my head now -------- if you have a salt water application, it probably is a consideration. Just a regular freshwater application is not so critical on the type of wire...BUT - I'm sure someone else can give you more professional advice than my previous recommendation - it was just my novice opinion and what I would do....... as far as the fuse, I would use an amp rating equal to or under the max amps rated on the draw (lights, bilge, etc.). With a larger wire size, you can bump up the fuse amperage a little also if you have a problem with amperage blowing the fuse.

All that being said, I would yield to any other opinions from members who are more knowledgeable.....


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## wasilvers (Jun 7, 2010)

bassboy1 said:


> I don't give a rats hind end what colors to use. On all my boats, I use red and black.



Ditto that, I used Red, Black, and White. Black was negative - which was shared with all accesories - so I didn't need as much - Red and White were positive. I figured I knew what was wired where and that was good enough. But I used white for lights, and red for accessories.



bassboy1 said:


> A fuse wouldn't hurt, but I wouldn't freak out about installing one on a light.


Actually, the fuse is to cut power from the battery in case of too much current draw (ie.. a short or bigger accessory hooked up). If you short out, hopefully the fuse blows and keeps your wiring intact, your gas tank from blowing, or the juice from cutting a hole in your aluminum boat, and your new 1197 Side Imaging from getting toasted.  

I fused everything except my electronics, but that was because it's hooked right up to the battery with a short cord and I ran out of time. It will be fused in a few weeks.

As to tinned wire, I don't know. I didn't use it because the last guys didn't use it. I looked at trailer wiring and it wasn't tinned, and that stuff gets wet all the time. I did solder all but 3 of the connections. I figured it's hard to corrode soldered connections.


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## bear7625 (Jun 8, 2010)

There is a site that's posted on material links that has great prices marine wiring.

https://tinnedmarinewire.com


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## huntinfool (Jun 9, 2010)

Personally I would go with the 20. But that is me. If in the future I decide to remove the light I can leave the wire and use it for something else. 

As far as color I use what ever I have. I like red for + and black for -. But I usually try and use the same color for all things on the boat. So red for + and black for- and then I use green for wiring lights, bilge, depth finders, etc.


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## longjohn119 (Jun 13, 2010)

Personally I don't use anything less than 16 gauge except for LED lighting. Larger wire = lower loss = longer runtime. Of course there is a point of diminishing returns but the difference in cost between 20,18 and 16 gauge wire generally isn't that much and just having one wire size is cheaper in the long run. Since the wiring in my boat is more complicated than most I have every circuit on a different color wire. That will pay off the first time I have to troubleshoot a problem, in fact it already paid off when wiring the main control panel. Not all of it is official Marine but all of it is tinned and the non-marine wire is better rated in all categories except saltwater use (That has more to do with the insulation than the wire itself)

As far as current draw that's easy Watts divided by Voltage = Current In this case 10 divided by 12 = .833 amps. (I can't stress the importance of learning Ohm's Law and it's variations enough, once it's second nature everything about electronics/electrical falls into place)

Also when you figure loss in wire for DC power circuits you have to take the length times 2, if you run 15 ft you need to figure the loss for 30 feet of wire because that's how far the electricity has to travel from the negative to the positive poles of the battery. (Some charts/tables figure it in but don't assume they do) The use of multiple ground busses and/or multiple batteries complicates things a bit but as long as your buss interconnecting wires are large enough you can stick with the length times 2 and be safe in figuring loss.


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## longjohn119 (Jun 13, 2010)

Also make sure it's fused somewhere, the fuse is not to protect your device it's to protect the wiring and protect from starting a fire. If your device goes bad and draws too much current or worse the wires short out, without a fuse you'll smoke the wires guaranteed and possibly set your boat on fire before the wires themselves act as a fuse and burn in two. A short in the wiring before a device rarely, if ever, harms the device, since the short is ahead of it there is no current flow through the device it's all shunted through the short ahead of it. If you are using a large fuse/breaker at the battery (commonly 50 amps) you are going to need another smaller fuse somewhere between your light's wiring and the breaker. Even 16 gauge wire shorted will smoke and flame long before the 50 amp breaker gets blown. 

Since your main concern is to protect from shorts and fires caused by shorted wires going up in flames you can gang several small devices on one larger fuse, say five 1 amp devices on a 10 amp fuse. (This is how every one's house is wired and again the fuses/breakers are not to protect your devices, they are there to keep the wiring and your house from going up in flames in case of a direct short) It's large enough so it doesn't blow because of in rush current (Mainly a problem with motors but also some switching power supplies in electronics devices) because of several devices turning on at the same time yet still small enough to blow before the current causes a heat problem and smokes the wire if you get a short circuit. Other possibilities are coming off the bilge pump or livewell pump fuse and use a 5 amp breaker, again enough headroom so it doesn't blow with both loads turning on yet small enough to protect the wiring from smoking in case of a short

We are running our wiring in, around, under, and through metal that is moving and flexing and also is a very good conductor of electricity so if it gets pinched or cut the potential is high for a direct short across the battery. A shorted 550 CCA battery can generate a lot of heat almost instantaneously and I've personally seen two boats smoke the wiring. One was just a few feet of wire and was more hilarious than dangerous but the other started two fires that had to be put out with a fire extinguisher and the guy was left stranded on a sandbar in the middle of the Mississippi. Luckily it was a popular site to party so he got a friend to tow him back but still who would want to be him?


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