To realize an eco-house, a new direct current (DC) distribution system has received widespread attention. This paper has proposed countermeasures to fundamental problems which make difficult to achieve a high-speed PLC over the existing alternating current (AC) systems. To reduce the signal attenuation of the conventional low-voltage (LV) power-line cables made from vinyl insulator, it is recommended to use cables made from polyethylene insulator. It has been also recommended not to use the single pole and 3-way switches supposed to be cut into the hot conductor, and hand-made joint boxes in order to make the electrical balance of the channel high. To prove these proposals, a DC power-line system of 1.5kW capacity was built and the throughput was measured. The proposed simultaneous dual-mode system performed 1.9 times better throughput at maximum comparing with the conventional single-mode system. From these observations, a scenario for a 1Gbps Personal Area Network (PAN) over the new DC power-line channels is proposed. ? 2012 IEEE.