A short stop is an automatic reset circuit breaker designed to protect the battery and the power supply in case of a direct short. It’s similar to the Utility company’s cut out fuses in the power lines or inside the pad mount transformers serving our homes. The circuit breakers in our homes protect everything inside the home. The utility company fuses protect the wiring coming into our home. Likewise our breakers (120v) and fuses (12v) protect our trailer devices (plugs, lights, a/c etc... and the short stop protects the wiring to the power supply from the battery.