I want to add a sub-panel to my detached garage about 50' away. I have a bunch of #6 wire I would like to use if I can. The black is marked "THW 600v". The red and white I have is marked "MTW - Type THW 600v. From what I've gathered a W in the wire designation means it is sutible for wet locations ie. conduit. I know THWN is suitable for use in conduit but I've never heard specifically that THW can be used. Does anyone know for sure?