Switch replacement amperage

adrianalindgren - October 6, 2022

Skills

I have a nilight lightbar which I have wired to my starter battery. The rocker switch that it came with is a 12v 20amp switch but that switch does not fit in the dash- and I don’t want to custom install it. I found a switch that fits perfectly in the blank spaces but it is a 12v 16amp switch. My question is how do I determine if the 16amp switch is sufficient for the application?

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How many amps of current does the lightbar draw when it’s on? It’s just a bunch of LEDs correct? No motors or moving parts (if there are moving parts, the answer gets more complicated)?

If you can find that answer in the manufacturer docs, and it’s well under 16 amps, you should be good.

If you can’t, you need to measure it with a multimeter. Set the multimeter to the amps setting on the dial, and make sure the positive lead is in the amps socket. Then you touch the two probe tips to the two wires that would connect to the switch, thus completing the circuit (the meter is taking the place of the switch temporarily, and the current flows through it, from one wire, through the probe tip and meter, out the other probe tip to the other wire). Write down the number you get, make sure to check what the unit is. 

One last detail, is the switch rated for 16 amps AC or DC? You would think that amps are amps, but it’s easier to switch off AC than DC, so the ratings are not interchangeable. 

Hope that helps, let me know if you have more questions.