"I just built a 50' x 100' metal building. I plan on using 60' of this bldg for and metal fab/auto repair shop. I plan to use the other 40' for a wood shop. I have a lot of equip to place in the shop (ie wire welders, metal and wood lathes, planers, jointers, autolifts, sand blaster, forge,metal and wood bandsaws, table saws drill presses, presses, etc.). I just acquired 24 240V 400W Metal Halide lights to install in the shop. I dont plan on running a business out of the shop. Its just going to be a place where I can work on all my projects when I retire in 3 yr. Its located in the country. I want to buy wire to run the electricity. Obviously I will be running both 120 and 220 circuits. Can you explain what the code (like THHN and AWG etc.) means and tell me what I should try to find. Any electricians I talk to say dont worry about it they will get the wire for me. They also indicate that it may cost me as much as $20K to wire my shop. I think I can save substantial $s if I just know what kind of wire to buy and wire it myself. I figure on using #8 or #10 stranded wire for 22O circuits and #12 solid copper for 12O circuits. I think I will have runs as long as 120 ft from the circuit box (200A 40 space Square D box)which will be located on one side of the bldg about 40' from the end. What kind of wire and conduit do you recommnend? and is conduit necessary?."