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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.

marked as duplicate by Pᴀᴜʟsᴛᴇʀ2 Oct 16 at 20:14

This question was marked as an exact duplicate of an existing question.

migrated from electronics.stackexchange.com Oct 16 at 19:38

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  • The 20 Amp rating for #12 wire is an Electrical Code specification for house wiring. #12 wire can safely handle somewhat higher current - you'll find tables giving higher currents for other applications. – Peter Bennett Oct 16 at 18:57

You look at the wire gauge, but also the material and the jacketing - as these affect heat dissipation. This should clarify: https://www.cerrowire.com/products/resources/tables-calculators/ampacity-charts/

  • This should help as well: offroaders.com/technical/12-volt-wiring-tech-gauge-to-amps – relayman357 Oct 16 at 18:10
  • 2
    Answers that consist mainly of links to other sites are not very valuable, because the links often break and leave the reader with nothing. You should try to summarize, without just copying, the important content of these two sites. – Elliot Alderson Oct 16 at 18:34

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