I am currently looking at a 32 inch 310 watt LED light bar for my 2010 Honda CRV. The light bar I am looking at is https://www.amazon.com/dp/B07MCNYXFT/ref=cm_sw_r_cp_apa_i_JpKPDbTR3J8R4.

The wiring harness I am looking at is https://www.amazon.com/dp/B074GYNJ85/ref=cm_sw_r_cp_apa_i_mqKPDb9945BNQ.

On Amazon it says that the wiring harness could handle up to 400 watts. However when I look at a calculator for wiring harnesses by gauge size, I get confused and it looks like it can't handle the load from the light bar.

The light bar will be connected to a 12 volt battery and since it is 310 watts I'm assuming that it would take 25.83 amps and from what I found 12 awg wire can only handle 20 amps.

I was looking to see how would I be able to know for certain that a certain gauge wire could handle a certain appliance. Thank you.

1 Answer 1


Short answer, yes this will be fine, however there will be some Voltage Drop, which likely won't effect the light output.

Calculating the voltage drop of these wires comes out be around 15% drop over the wires. This is because in truth that wire gauge is not Ideal for 26 amps. However, in free air (chassis type wiring), where the cable is not bundled up with other cables and is able to easily dissipate its heat, it is not going to be an issue in terms of any heat output.

I would feel happy using that wiring size.

However, looking at the reviews for that product, there appear to be some reports of badly wired connections so do a double check of everything before you install!

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