I'm pulling 100 amps off my main house 200 amp service to my new Garage. It is an indoor run of 70 feet. What size wire do I need? Copper or Aluminum? How many conductors? If I run it in the joist space do I need to case it? Thanks Ron

What size wire do I need? That depends
Copper or Aluminum? Either
How many conductors? Four
If I run it in the joist space do I need to case it? What does "case it" mean?..........

Hey bet "case it" means enclose in conduit. The answer is no.

Aluminum is usually cheaper, but it requires extra care and anti-oxidizing paste.

Hey bet "case it" means enclose in conduit. The answer is no.
Yeah, I know. It's just the OP is once again so vague we would be guessing at most answers.

If cable is run no conduit is required.
If individual conductors are run then yes, conduit is required.

Case it? Yes I was talking about conduit. I live in Hugo MN. Someone told me I could not use aluminum indoor. Is that true? Ron

Aluminum can be used indoors unless your state expressly forbids it.

I am pulling 100 amps from my 200 amps home main service to an attached garage sub panel. I have been told that I cannot use aluminum wire. Is that true? I had planned to use #2 aluminum wire. Now I'm told to use #4 copper with #6 ground.

Did a search for Minnesota Electric Code and found this:

Electrical codes and standards information (http://www.electricity.state.mn.us/code_standards.html)

What an awesome site, easy to find, all the information regarding the electrical trade needed is there. Much better than some states.

I found this:
http://www.electricity.state.mn.us/pdf/20000331_2.pdf

Explains about aluminum wire, no where does it state is is not allowed.

Then I found this;
http://www.electricity.state.mn.us/pdf/laws_and_rules.pdf

Seems to be the actual statutes, aluminum is not even found in the entire document.

Looks to me that aluminum is allowed.

Who did you get your information from? Clerk at hardware store? Some do it yourselfer?

Start by applying for a homeowners permit:
http://www.electricity.state.mn.us/pdf/eli_rei_homeowner_form.pdf

While I find that the homeowner APPLIES for the permit, I find NO mention of ALLOWING homeowner to do their own electrical work.

Contact someone at the state:
Minnesota Electrical Licensing and Inspection (http://www.electricity.state.mn.us/index.html)

And ask them the questions you have, and you will get the true and accurate information.

You already have this exact thread going. WHY start a new one??

https://www.askmehelpdesk.com/electrical-lighting/pulling-100-amps-main-200-amp-service-345697.html#post1690268

Followup:

Seems homeowners are allowed to do their own work, "within strict limitations", as found here:

http://www.electricity.state.mn.us/pdf/rei_inspection_checklist_brochure.pdf

And the actual statute referred to:
https://www.revisor.leg.state.mn.us/statutes/?id=326B.31

You really should contact the state AND local inspectors to learn the process of doing your own work, and any requirements or waivers of the National code.

While aluminum wire may be allowed, which is fine, there are issues with connections and terminations, and these must be done correctly.

Typically, you should be able to use #2 aluminum 4 wire SER cable , for a 100 amp residential feeder, and follow the manufacturer's installation instructions for terminations.

Conduit will be needed where the wiring may be subjected to physical damage. You may or may not be able to recognize where this may occur. Inspector will find it and make you install in conduit. Better to plan this out, learn what will be required and install it properly the first time.

One issue is, inspectors DO NOT design your system, many will not offer advice, some will, they will pass or deny based on what they see and based on code.