Electrical – What size and type wire should be used for 100 ft away work shop

If it were me I would probably run 4/0 and mount a 100amp double pole breaker to feed it in your main panel. I'd come out of the breaker with #2 copper and then use a barrel connector to transition to the 4/0 aluminum on each hot line.. Then go the 200 ft in a conduit. In theory you don't need it that thick but I bet you would appreciate the less flickery lights when you turn on heavy loads out there.. You could also do direct burial, they make service cable that is approved for burial and you get a higher rating when buried in dirt because it is basically water cooled. 600v insulation, etc. If you make that trade off you may get annoyed every time you kick on a motor on. They make ul approved barrel connectors for the transition from #2 coper to 4/0 and aluminum and Home Depot carries them. The county inspector approved this method for me. I would call your local inspector and ask him. They are often helpful for the Diy folks when not swamped. Try again in early mornings before they are about, and try more than one..

Jeff

Of the options you are considering, I'd think option 2 makes more sense, and 4-5 feet of conduit - in most cases the conduit will just be continuous from the junction box right through the wall, no particular fuss "as it enters the house" - Come down the wall, put on an LB, drill a hole in the wall, insert conduit, connect to junction box, connect to LB; done. This might be aided by drilling at least a pilot hole from the inside out to make lining it all up easier. Also pick up some duct seal (gray putty, in the electrical aisle) to pack the wires as they leave the LB.

If the wires are entering via an existing conduit, you just need to connect a new conduit to the box that conduit terminates in, and your junction box.

EMT or PVC is six on the one hand, half a dozen the other. I use metal aboveground and PVC below, mostly.