Circuit protection device for photovoltaic systems

Abstract

A circuit protection device for protecting a photovoltaic (PV) system from an overcurrent condition. The circuit protection device includes a first electrode electrically connectable to a first line of an electrical circuit, a second electrode electrically connectable to a second line of the electrical circuit. A first thermal element, second thermal element and an overload assembly define a first conductive path between the first and second electrodes. A bypass shunt defines a second conductive path between the first and second electrodes. The overload assembly electrically connects the first thermal element to the second thermal element, and is moveable between a closed position and an open position (i.e., overload condition). A low melt temperature solder electrically connects the overload assembly to the second thermal element. The low melt temperature solder softens and melts as the temperature increases in response to an overcurrent condition. Consequently, overload assembly moves from the closed position to the open position, thereby opening the first conductive path between the first and second electrodes. Residual follow-on current flows through bypass shunt via the second conductive path until the bypass shunt melts.