Stranded wire vs solid for diode connections

[tundrawolf]

Hello, I have a 110 volt welder that I am replacing the diodes and heatsink on. Really I am putting heavier duty diodes, thick, finned heat sinks and a fan, in the welder, I am re engineering it. I am using 10 gauge wire to wire the assembly together. I tried using solid core wire and due to the proximity and lack of flex, I tore the entire diode housing in half. So I am wondering what the drawbacks, if any, are with using stranded wire for the diode connections.

[DougAustinTX]

Stranded wire can carry more current than single conductor. More surfaces for the electrons to move on.

[awright]

DougAustinTX said, "Stranded wire can carry more current than single conductor. More surfaces for the electrons to move on."

Not actually of any practical significance at utility frequencies for conductors of the size you would use in a 115 volt welder. True in small conductors at high frequencies at wihich the "skin effect" influences how electrons flow in conductors because the "skin" is thin or at low frequencies in utility size conductors. At 60 Hz. the "skin depth," i.e., the thickness of the skin on the surface of copper conductor that carries most of the current is about 8 mm, so it would not have any practical effect inside your welder.

At 60 Hz the difference in ampacity of stranded vs. solid conductors would be the amount of conductor surface area from which heat can be conducted away from the conductors, but the difference is small. I hesitate to say negligible without researching it, but I wouldn't worry about the difference. The only practical difference would be fatigue resistance of stranded vs. solid but there would not be enough vibration or wire flexing inside your welded to make any real difference.

Use what is easiest to install or what you have on hand.

awright