In actual production and daily life, non-linear loads such as LED lights and LED screens are widely used. Such devices generate 3n harmonics, resulting in an excessively large current in the N line. The N line curent can be managed by configuring neural line safety protector (SNP) at the terminal. When there are a large number of SNP devices, the inspection personnel need to check them one by one, resulting in relatively low operation and maintenance efficiency. When there is an overcurrent in the N-line or other faults, timely feedback cannot be obtained, and ultimately, the SNP is damaged, causing economic losses. This paper proposes a method for N-line overcurrent protection and detection based on neutral line safety protector, which is realized through the internal hardware circuit. When the current value of the N-line exceeds the set value, the internal relay sends a dry contact signal to control the shutdown and alarm of the SNP. At the same time, users can monitor data and control the operation through the WiFi module and the network communication circuit. Finally, the practicality and safety of this method are verified through experiments. It has the advantages of providing timely feedback of information, protecting the safety of equipment, and facilitating operation and maintenance.