GROUNDING DEVICE

There is provided a grounding apparatus capable of instantaneously opening the current path when a complete grounding fault occurs between the ground point and the ground line, which is provided between a solar cell and an inverter, or opening the current path when an incomplete grounding fault occurs between them, or generating an alarm while keeping operation. The apparatus includes an inverter (3) to receive DC power of the solar cell (1) through a DC positive bus (11) and a DC negative bus (12) and to covert the DC power to AC power to be supplied through an insulated transformer (10) to an AC power system (8), a circuit breaker (21) connected to (11, 12) and configured to open a current path between (1) and (3) when a current flowing in the current path exceeds a first protection setting value, a ground line (25) connecting (11) or (12) to the ground (26), a current detector (23) to detect a current flowing in (25), a fuse (22) inserted in series in a part of (25) and configured to melt when the current flowing in (25) exceeds the first protection setting value, not destroying (23), and then exceeds the first protection setting value, causing a complete grounding faulty and a determination device (24) to give an open command to the circuit breaker when the current detected by (23) exceeds the first protection setting value of (21).