Edward asked in Science & MathematicsEngineering · 7 months ago

what size of copper conductor should be used to draw 25 amps of current?

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• Vaman
Lv 7
7 months ago

Some home appliances draw 16 amp current. The diameter of these wires is 3 mm and about. Make it double. The wire should be 5 mm thick for the safety. Please check the rating. The best is to visit battery charger shops. They use very high currents 16 amp and above. Check the diameter.

• 7 months ago

The normal method is to apply full load current and then multiply by 125% and find a wire whose ampacity is just great than that product. So, 25 x 1.25 = 31.25A. From most NEC tables, that is slightly greater than the ampacity of a #10AWG wire. The minimum size should be at least a #8 AWG conductor (without taking Voltage drop into consideration).

• 7 months ago

AT LEAST GAUGE AWG#10 COPPER WIRE.

• Anonymous
7 months ago

If you're using THHN you can get away with number 12. but when I'm dealing with the maximum load that you can possibly put through wire without it getting hot I'd rather go one size bigger and go with number 10 and not stressed wire out to the absolute maximum amperage that you're supposed to run through it. Be it on the safe side and go with number 10.

• 7 months ago

Hmm, building or automotive?

Automotive I would use #8 up to 20 feet, if feeding to a trailer #6.

In the US the NEC requirement minimum for 25A peak on a fluctuating load #10 THHN copper. If HVAC, motor, constant 3+ hours load, or other 125% application (31.25A) then #8 cu would be required.

Additional code sections may require additional adjustment such as length of circuit, inferior insulation, or other condition specified in the installation instructions.

• 7 months ago

depends on many factors, such as max voltage drop, length, allowed temperature increase. And wire code if applicable.

For example, for a 1 ft length, US AWG #14 would drop 0.06 volts.

for a 100 ft length, you would need something like #8, which would drop 1.6 volts.

now if this was a 100 volt circuit, those voltage drops would probably be OK. But for a 5 volt circuit, 1.6 volts drop would be too much.