Please tell me you didn't learn that at the shop !!At DC (like your cars electrical system) the current flows through the ENTIRE thickness of the cable. With AC (like sine waves, music, or your home electrical system) the current flows through the entire thickness of the cable at low frequencies. As frequency increases it gradually begins flowing through less of the cable thickness and more towards the surface of the cable. HOWEVER, over the audio bandwidth (up to 20khz) the current still flows through the majority of the cable thickness. Skin effect for our purposes can literally be ignored. It does not exist with DC and with AC, over the audio bandwidth, it is not a factor. It's a non-issue for us. It doesn't become a real consideration until the MHz range (think radio frequencies). The ONLY thing strand count affects for our purposes is flexibility. It doesn't flow more current. The only thing you need to be concerned with is conductor cross sectional area (other than the difference between OFC and CCA), and no matter how many strands the wire has true 0ga wire will have the same conductor cross sectional area. And conductor cross sectional area can not be measured simply by measuring the overall diameter of the wire in the jacket for multistrand wire like so many people on the internet try to do.