Whats crazier is that in direct current individual electrons don’t travel at the speed of light through the conductor, but only at roughly 1cm/s.
Or, that thanks to the “skin effect” the current actualy travels in a very thin layer below the outside surface of cconductor. Most of the conductor doesn’t transfer power but only maintains the magnetic field to keep the current flowing.
No, skin effect only occurs on higher frequencies. That is why coaxial cabel is invented. But then they realized the energy in coax transfers in a completely different way.
I’m far from an expert, but that’s usually just for flexibility of the cable as far as I understand. Power wires inside the walls are one thick copper wire (or rather three for live, neutral and ground)
Well the “multiple thin wires” technique (litz wire) is more complicated than just having multiple thin wires (you need to braid them in a particular pattern because the magnetic fields that flow through the wires act on each other as well). But it is absolutely used for mitigating the skin effect as well.
Power lines inside residential homes are an exception because the frequency isn’t high. The skin effect for copper at that point is about 8.41 mm.
Even the thickest wires for carrying 300 amps has a radius less than 6 mm (you can also see that the rated frequency is 125 hz).
If you want to calculate the skin depth, use the formula , where f is the frequency, p is the resistivity (copper - 16.78 nano Ohms), u is the permeability (copper - 1.256 micro Henry/meter).
Whats crazier is that in direct current individual electrons don’t travel at the speed of light through the conductor, but only at roughly 1cm/s.
Or, that thanks to the “skin effect” the current actualy travels in a very thin layer below the outside surface of cconductor. Most of the conductor doesn’t transfer power but only maintains the magnetic field to keep the current flowing.
No, skin effect only occurs on higher frequencies. That is why coaxial cabel is invented. But then they realized the energy in coax transfers in a completely different way.
That’s why you don’t have one thick copper cable but multiple thin ones.
I’m far from an expert, but that’s usually just for flexibility of the cable as far as I understand. Power wires inside the walls are one thick copper wire (or rather three for live, neutral and ground)
Correct, solid copper bus bars are also common in certain applications.
Well the “multiple thin wires” technique (litz wire) is more complicated than just having multiple thin wires (you need to braid them in a particular pattern because the magnetic fields that flow through the wires act on each other as well). But it is absolutely used for mitigating the skin effect as well.
Power lines inside residential homes are an exception because the frequency isn’t high. The skin effect for copper at that point is about 8.41 mm.
Then consider this wire gague chart
Even the thickest wires for carrying 300 amps has a radius less than 6 mm (you can also see that the rated frequency is 125 hz).
If you want to calculate the skin depth, use the formula
, where f is the frequency, p is the resistivity (copper - 16.78 nano Ohms), u is the permeability (copper - 1.256 micro Henry/meter).