A general contractor usually is responsible for the supplying of all material, labor, equipment, (engineering vehicles and tools) and services necessary for the construction of the project. To do this it is common for the general contractor to subcontract part of the work to other persons and companies that specialize in these types of work. These are called subcontractors. General contractors construct the project. Subcontractors supply the equipment/supplies. General contractors conducting work for government agencies are typically referred to as prime contractors. The responsibilities of a prime contractors working under a contract are essentially identical to those outlined above. In many cases, prime contractors will delegate portions of the contract work to subcontractors. ex. if i do home remodeling,baths, kitchens,windows but u also need a concrete patio and i dont do that, i would hire a person who does concrete.he is the subcontractor.