Unbalanced loads are carried back thru white colored wires to the main neutral bar in the main breaker panel. (white is grounded-conductor). The unbalanced load is balanced while traveling thru the main breaker panel neutral bars out to the primary transformer and back. The ground or green wire carries overloads back through the grounding(green) part of the system either tripping the breaker or dissipating through the bare copper(or aluminum) grounding conductors to the grounding rods outside the building. All home circuits have very small overloads happening all the time. Breakers are designed to withstand very small amount of overloads.