Once the solar dc cable in the roof solar cable trough is short-circuited, its fault will always exist, which will cause the cable to catch fire for a long time. Even after a person goes on the roof, he cannot cut off the power supply by simple operations, and can only cut off the photovoltaic module power supply by cutting the solar cable, which is very dangerous.

The short circuit of solar dc cable can be viewed from two aspects.

First, the quality of the solar cable and the construction quality during installation determine the probability of a short circuit in the DC cable. If the solar cable itself is a certified weather-resistant DC cable, and at the same time it can ensure that the construction meets the national electrical standards, then the solar dc cable short circuit is a small probability event.

Second, the fundamental solution is to install a disconnect device in the component end junction box. So once the photovoltaic array has a problem, whether it is a short-circuit of the photovoltaic cable or not, the line can be cut off from the module end, so that the entire array is in a dead state until the AC output of the inverter. It is based on this consideration that the installation of quick-shutdown devices for rooftop photovoltaic systems in North America is based on this consideration.