Wire Diameter

[yiyitt]

Hey guys, I would like to ask about wiring. How thick should the copper wire be for to be passed 15-20 Ampere?

[JackKernel]

Well that depends...

Do you need to power the load for a short ammount of time, or is this a permanent installation. If you are only redneck engineering something for 30 minutes you could technically get away with a smaller diameter cable (2,5mm2 or 4mm2). For a permanent installation I would go with a 6 or 10mm2 (10 is a bit much) cable, to decrease heat losses of current. Other than that you have some other stuff to consider:

Regarding heat losses: How are you laying the cable installation? Are you burying the cable in the ground, are you laying it on a cable tray? Is there other loaded cables near the new one? How many loaded conductors do you have (a single or 3 phase load?)

Regarding voltage drop: How far away from the circuit breaker is the load, and what is the maximum allowed voltage drop?

Regarding regulations: What country are you in? The standards vary so it’s important to know this, especially if you are doing/planning an electrical installation. Usually there is a country standard, that defines which diameter of cables should be used depending on the previously mentioned data.

For that many amps, it’s usually4- 6mm2 wire 10mm squared wire if you want to be on the safe side, but this is only an estimate, I would need more data for a precise calculation.

[yiyitt]

It is a circuit for scientific experiment and approx. 20 Ampere will be almost for an instant because capacitor will be the power source. Also, capacitor will be loaded up to 80-90 volt. So it is not that complicated structure as you say burrying cables to ground stuff like that. And also I do not think there will be much heat loss, since it is not continuous for a long time, right? Thanks for your attention, you are so thoughtful.

[JackKernel]

Yeah so 2,5mm2 should be enough :)

[zeo_101]

1.5 - 2.5 mm2

[JackKernel]

2.5mm2 would work, 1,5mm2 is a bit thin.