# wire gage help



## bamabill (May 28, 2015)

What size wire would I use from my starting battery to my buss bars? I'm using 14 ga. from my buss bars to the switch panel and all accessories which only amounts to led lights, bilge pump, 12 volt receptacle, and electronics. Thanks.


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## DaleH (May 28, 2015)

Depends on the total length of the run, which means distance to and back (round trip). I would guess at least 10 AWG, but see the chart below and assess what your *worst case* total amp load would be.

An _example_ (using the 3% max voltage drop chart), say a 16 to 18' total run, where you need to carry 20 amps ON at any one time ... that means you read the *green colored band *to determine the wire size needed, which is 10 AWG.

14 AWG may be overkill for most of those circuits to the items, less maybe the bilge pump. LEDs are well < 1-amp each, usually in the milliamps. Small pumps 3-5 amps, mostly due to starting voltage, and fishfinders are 1-2 amps. I've used 16 AWG for most load items and 18 AWG or smaller for LEDs and other ultra-low voltage items and have never had an issue. The only time I'll do a calculation for stuff like that is high draw or safety items, e.g., bilge/storm pumps, or that accessory 12V socket that you never know what someone may stick in it.

Your items spec sheets or manuals list the amp draw. And if you use something like a spotlight measured in watts, just divide the wattage (say 55 watts for a 12V spotlight) by the DC voltage, to get the amps. _Example_: 55 watts / 12.6 (nominal VDC) = 4.4 amps.


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## bamabill (May 28, 2015)

thanks Dale, the only reason I was going with 14 is because it was free. thanks for the chart, that will solve everything.


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## Skiffing (May 29, 2015)

You can double up the 14....
2 positive & 2 negative runs

Electricity travels on the surface of the wire. The wire gauge relates to "circular mils" which is the outside surface area.

If you use 2 runs of 14 gauge wire you will double the circular mils:

Double the amperage carrying capacity and cut in half the voltage drop.


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## BigTerp (May 29, 2015)

Dales chart is exactly what I used when figuring out what I needed for my wiring. Most of my accessories called for 16 gauge wire, but my stereo and bilge pumps called for 14 gauge wire. So, to keep things simple I went with the larger 14 gauge wire for everything. It's OK to go larger (within reason) but you definitely do not want to go smaller. Everything has been working flawlessly since I did my wiring 2 years ago.


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## sonny.barile (May 29, 2015)

If you listen to the guys in West Marine you will be wiring everything with 6 awg solid. LOL


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## henro (May 29, 2015)

Good info in here thanks guys.


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## bamabill (May 31, 2015)

I went ahead and ordered some 16 ga. marine. I like the idea of tinned wire. Another question, can I operate a fish finder and a Hummingbird Super 60 flasher off the same transducer? Does that even make sense? I've included a pic of some goodies I got for my makeover posted over on another forum.


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