I'd install a sub-panel in the garage with power being fed from the main panel in the house. The service to the main panel may also need to be upgraded if it is not adequate to support the additional load.

So this would mean using PVC pipe to run the main wire to the garage and bury in under ground

Conduit (which might be PVC but you can't just use PVC drain pipe) is probably the best bet. You might be able to direct bury.

You'll need a grounding system at the new building. New construction will require arc faults in those living spaces and gfci within the garage. Frankly, I'd be getting smart on the codes if you're going to do this yourself if you want to avoid heart ache. There is special considerations (non-electrical) for living spaces over garages.

In my area, a second service to the same piece of property
is 'full billing', meaning you will have to pay them several hundred dollars to run the service. Besides, they
will need a 'certificate of occupancy' from the civil division that you reside in. And then,. . . you will have
a meter charge on that second meter, (look on your current
bill and you will know what that is). Check with your
utility company on these issues.

I forgot to add: if you can't get the 'certificate of
occupancy', then the utility will still hook you up,
but you will be paying a commercial rate for your
'garage'.

Ronnatalia what do you mean by special considerations (non-electrical) for living spaces over garages Could you explain a little on that? We are going to have a Lics.Electrician do the work for the most part for sure. We just had not even given a though yet as to how do we get power to the new garage, Actually the garage will be more of a work shop. Hubby is a lobsterman and needs to work on his traps during the winter months. upstairs will not be living space for some time mainly storage
untill we get Money to finish it but we will be getting the power run through out first.

For got to mention this work shop/garage will never have any type of plumbing or water installed to it if that makes any difference no bathroom ..upstairs no water or plumbing either

This is off topic for the wiring forum, but you have to separate living spaces from garage areas by a firerated wall/ceiling and doors that vary with local codes. In addition there are considerations when putting space OVER the garage with regard to ceiling penetrations (don't want CO getting up into the living space).

Dear Gardenandcats,
If and when someone inhabits these 'bedrooms',
where are they supposed to poop and pee?
(by the way. . . You're welcome!!!

We are putting in a waterless type toilet either the gas that incinerates or the composting type. As we will have no cars in the garage its more a work shop not car storage CO is not a problem thanks for your help and
info

I promise this will be the last off topic queastion. why would the code ask for firerated wall/ceiling and doors above a work shop and not a whole house?I take it this is different types of building materials then what is used in your home?

The code refers to a garage attached to living quarters. The topic is New garage with two bed rooms above wiring? hence the references to a garage code.

A double layer of 5/8 drywall with self closing doors for firerated. If you do not put garage doors on the workshop another thread can be started with the workshop as a topic.

ok thanks