Garage Project-Electric Feeder?

I built a detached garage and want to put a 100amp subpanel. Want to keep the 328 warm this winter. Montgomery County md. The feeder will have to snake from the main panel across unfinished basement to about a 45 foot run underground. 85-95ft run total. Any recomendations on type of feeder wire? Cu vs Al? It would be difficult to run conduit in the basement so if I would have to run romex from the panel to a junction box and THHN thru the conduit to the garage. Talked with one guy that recomended using #1 Aluminum the whole way, any master electicians in the group?

 

pm sent

 

definitely aluminum . copper of that guage is crazy!
you need to contact an electrician to do a heavy up. itll knock your socks off if you make a mistake. not worth it. you ca npre dig the hole and mount the box though...

 

i did the same thing down here for my garage. i used aluminum cable and ran it just as you say; run from the main panel in the house to a junction box with a gasket then in underground conduit to the garage. it's a pretty straight forward process. if you can install a new breaker you should be able to diy. you just need to be sure your main panel is rated for enough service. you should be ok if you have 200 amp service. if you use a 100 amp breaker in the main panel you wont need a main breaker in the sub panel. just get a box with bus bars. i use square d. don't cut corners. take your time and be safe. it's not brain surgery. but if you're not confident about the hook up do the grunt work yourself pulling wire, digging the trench and burying the conduit. bury it 18"-24" deep. that way you'll only have to pay the eletrician to make the final connections. but then again there may be permit complicatons invovled with an electician.

 

Did you have to switch the type of cable you used at the junction box at the point where you went from no conduit in the house to underground to the garage? If not what type did you use?

 

PM Sent

 

I didn't have that long to run, and used copper. I also had a master electrician in the family so I got a deal on the #2 and #4 copper. I also figured I might as well do it right once. I'm sure you'll be fine with whatever you choose though.

Question, are you running a pvc conduit through the basement foundation wall? If so be sure to rent a core drill or a heavy duty hammer drill with a core bit (we used a brand new bit and going through 60-year old cured concrete with rocks really took it's toll.

For heat are you doing a mini-split heat-pump system or a heater only?

 

I used #4 copper for a 110 foot run to a new 100 amp subpanel for my new garage. Bought a 500 foot roll, and used 4 equal pieces, even though the ground wire did not need to be the same size. Use lots of lube to make the pull.

BT

 

We have not pulled yet but we will next week. I am using #1 cooper on a 100 foot pull. It will be pulled to a 150 amp panel.

 

My problem is THHN has to be run in conduit and part of the run has to snake through the basement. Conduit of that size would be a real pain to run in the basement and up through the wall to the main panel. What I am trying to avoid is having to splice two different wires when I transition from the basement to the outside trench. The first 30 feet will be inside the house to the back wall and the rest will be through conduit to the detached garage. Romex can be run inside without conduit but can't run underground in conduit. THHN can be run underground in conduit but can't be run inside without conduit. Direct burial Romex is outragous(approx $800) and is hard to pull for that size.

 

For heat I bought a Reznor UDAP75 propane fired unit heater. 75,000 BTU and is designed for low ceiling height use. Only hangs down 16 inches. Set a propane tank out back, no natrual gas unfortunatly. Bought it online for around $700 delivered. Figured heat pump would not be good for what I want. I'm going to keep the heat very low 50 degrees or less most of the time and want to be able to turn it up and have it heat fast when I go out to work on something. Garage is 1,100 sq ft so should be able to heat up pretty quick. Need the 100amps mainly for TIG welder.