Abstract: These include the overheating and burning out of low-voltage lines at heavily loaded nodes in urban villages, neutral line disconnections causing voltage instability, frequent trippings of main leakage protectors triggered by line grounding in rural areas, and undetected line faults leading to heat generation and arcing, eventually resulting in fires. Such issues directly cause casualties and property losses. This paper investigates a common wiring issue among low-voltage users, namely the incorrect use of the neutral line from the neighboring distribution area, which results in household voltage instability and the failure of electrical equipment to start. Through methods such as case analysis and simulation verification, this study analyzes and discusses this fault phenomenon theoretically.