Choosing correct wires for power regulators

Thread Starter

Sasuke Uchiha

Joined Jan 15, 2022
21
Hi.

I have a 20V battery connected to my pcb. I need a 5V/3A output, so I am going to solder a 5V step down module to my circuit.
Since I know a USB C cable can handle 3A, I am going to wire a USB C cable to the output pins of the step down module. At 5V/3A, that will be a total of 15W going through the cable. I am not sure if the same cable type can be used for the input since the voltage from the battery is 20V. Making it 20V*3A = 60W going in to the step down module through the cables.

I have seen AWG charts, and they don't mention anything about voltage or wattage. How do I know if the USB C cable will be safe to use for the input of the step down module?
 
While it is true that the only important thing when selecting a conductor is the amperage, the voltage levels to be used must also be taken into account for insulation reasons. In your case, with 20V it is correct to use the minimum insulation, except for the bare conductor case obviously.
 

DickCappels

Joined Aug 21, 2008
8,834
While it is true that the only important thing when selecting a conductor is the amperage, the voltage levels to be used must also be taken into account for insulation reasons. In your case, with 20V it is correct to use the minimum insulation, except for the bare conductor case obviously.
You might find it in the manufacturer's catalog. I usually go by wire gauge or copper cross-sectional area.
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You find these charts by searching for Electrical wire table. Searching for Wire Table seems to bring backyard and lawn furniture : -)
 
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