Although machine tool wire is qualified for many wiring applications it is a simply constructed wire that is made up of a highly stranded bare copper conductor. This high stranding of bare copper gives the wire its superior flexibility compared to that of THHN building wire. The bare copper conductor helps to keep the overall cost of the wire down as opposed to its sister Thermoplastic Equipment Wire, or TEW that is made with tinned copper conductors. The difference of bare copper vs. tinned copper gives the installer the option to choose depending on the application and personal preference of the individual. The tinning is to assist in the soldering process during installation and to help defend against corrosion.