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Do DC amps need to be rated to 80% of the circuit breaker size like AC amps do?
I have a marine battery charger that needs + and - cables but dont know what size wire I need, the charger has an output of 12v 15A DC. so with the 80% value I'd need the next wire size up which is 12gauge @ 20A. Is this correct? it seems like like its really small wire compared to actual real jumper cables
 

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Do DC amps need to be rated to 80% of the circuit breaker size like AC amps do?
Where did you hear this myth???




You have a charger, not jumper cables. BIG difference.
#14 or #12 will be fine for what you are doing. Unless of course the length is pretty long, like over 50'.
 

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What he said. Jumper cables are required to carry a LOT of current for a very brief time span. Not the same set of requirements for a charging circuit.
 

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it seems like like its really small wire compared to actual real jumper cables
Ever look at the cables that connect to your car battery? They are probably #4 copper stranded wire. That is because when you energize the starter motor, especially in cold weather, it draws lots of current - maybe even a 100 amps. Jumper cables have to support this current draw too. For your charger use #14 stranded wire, it will be fine, and #14 rip cord is a good choice. When you charge a battery it only draws heavily for a short time and then the current will taper off as the battery charges.
 
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