Re: residential garage not attached to house
Do you mean you wish to supply 2 circuits to the garage or, omce at the garge you wish to supply two circuits?
The first would not be permitted unless you install a multiwire branch circuit. If you are installing a feeder to the garage, a panel will be needed as you will have to provide overcurrent protection for the 2 branch circuits. The feeder disconnecting means will have to be rated at least 30-amperes. Running 2 circuits utilizing a multiwire branch circuit and calling it a single circuit will require disconnecting means of at least 15-amperes.
The feeder option will require a grounding system established at the building. If installing the single branch circuit, you will not have to establish the grounding system.