Abstract: Avoiding accidents caused by phase mismatch during the switching process of dual power sources is a goal that the power system operation department always pursues. Therefore, dual power lines or equipment need to undergo phase verification before being put into operation. The traditional low-voltage bus duct core phase work is completed by three people using a multimeter. The disadvantage is that the core phase personnel are relatively close to the exposed part of the bus duct, which can easily cause electric shock accidents and relatively low efficiency. This article introduces a new type of low-voltage bus duct core phase transformer, which can achieve two people to complete the core phase within a safe distance, effectively improving work quality and efficiency.