For saving energy and reducing costs of the burn-in testing of an uninterruptible power supply (UPS) system, a self-load bank using the circulating method is proposed. The AC/DC power converter of the tested UPS itself is used as a nonlinear load, the tested current flow as a form of circulation, and the power of the tested load is controlled by a DC regulator also supplying the energy loss of the tested UPS. To test a linear load, a regulator is used to regulate the load characteristic. From the experimental results the energy saved in the burn-in test is approximately 80% of that lost by the conventional method, using a directly connected RLC or rectifier load.