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).