wire thickness gauge

[nissannavaramog]

Hi Guys

Im trying to find out how you know the difference in wire thickness/gauge?

I have no idea, is it the thicker the better.

Im wiring up drive lights and want to know what gauge wire i should use etc.

Thanks

Rob

 

[Navmania]

Hi mate
Bigger is always better. But it depends on how many watts your lights are and how long the wire is to reach the lights. You will need bigger wire the longer the length to the light. Use a good multi strand wire to. Use this to work out how many amps you will be drawing and use bigger wire than needed. (Watts divided by volts = amps) so if you have 130watt lights divided by 12 volts = 10.8 or say 11amps each. Then times that by two for the two lights that gives you 22 amps total so you would run a 30 amp relay and wire to do the job. That's how I have always worked it out and have never had any problems. But all the auto Leckys out there will probably have a more exact method. You can also buy a spotlight plug and play harness from super cheap that will do the job for 130 watt spotlights. Comes with everything you need switch and all. I think it was around $30.
Hope this helps a bit anyway.

Cheers Brad.

 

[Old.Tony]

Pretty good advice there. You could use a larger relay if you want, there's no issue with bigger, but you can't skimp and use a 10A relay for 20A of power, the relay will die quickly.

There are two measurements for wire thickness and there are two primary types of wire.

Wire thickness can be expressed in Gauge (GA), AWG etc - and when it is, the smaller the number the larger the wire - so 2GA cable is bloody heavy stuff (like your small finger) and 16GA is like a noodle. You'll also see it expressed in mm2 (square millimetres). In this case the bigger the number the bigger the wire.

Wire types are either multistrand (highly flexible and suitable for mobile environments) or single core (commonly found in houses). Single core wire breaks easily when moved a lot - which you obviously don't get inside the walls of a house, but you do get in a motor vehicle.

So, +1 on Navmania's advice!

 

[mitch92]

Pretty good advice there. You could use a larger relay if you want, there's no issue with bigger, but you can't skimp and use a 10A relay for 20A of power, the relay will die quickly.

There are two measurements for wire thickness and there are two primary types of wire.

Wire thickness can be expressed in Gauge (GA), AWG etc - and when it is, the smaller the number the larger the wire - so 2GA cable is bloody heavy stuff (like your small finger) and 16GA is like a noodle. You'll also see it expressed in mm2 (square millimetres). In this case the bigger the number the bigger the wire.

Wire types are either multistrand (highly flexible and suitable for mobile environments) or single core (commonly found in houses). Single core wire breaks easily when moved a lot - which you obviously don't get inside the walls of a house, but you do get in a motor vehicle.

So, +1 on Navmania's advice!

Sort of.

Another common used one in auto is just mm. Quite common to see say 6mm auto cable. When that happens look for what it is in mm2 to get the current capacity, as 6mm auto will be only around 4mm2.

Also domestic house wiring is still multi strand. Normally 7 strand (till you start going bigger), but thick strands. Auto cable is flexible by using many more cores of smaller diameter.

 

[terryc]

Yep, as mitch pointed out, a few of the wire gauges actually measure the outside diameter of the cable and insulation dos SFA for current carrying.

Here is a good table http://andersonpower.com.au/wire-sizes-ezp-11.html
and if you go andersonpower.com.au -> categories -> cable and wire it will show you what they have. I also noted they currently have a 20% off offer(but no delivery till April 22)

The easy way is just to buy the thickest cable you can afford and that will fit in.
If it runs warm, then it is too thin.

My quick 2c is use the 4mm2 cable from battery to relay and individual 2.5mm2 cables for each spot fro the relay. Caveat, run length. I actually use these for lighter current over 5m and 10m runs.