Voltage transformers (PTs) and current transformers (CTs) are crucial electrical equipment in power systems, responsible for isolating high- and low-voltage systems and converting high-voltage signals into low-voltage signals. The correctness of their wiring is crucial for the proper operation of system protection, measurement, and inspection equipment. When commissioning new PTs and CTs or replacing their secondary cables, verifying the correct wiring of these devices using a test method has become an essential procedure for relay protection operators. Preventing reverse wiring requires locating the "same-named terminals" of the transformer's input and output, a method known as "pointing." This article uses a current transformer as an example to illustrate how to do this. The specific method is to connect the pointer multimeter to the secondary output winding of the transformer, and set the multimeter to the DC voltage position; then fix the negative terminal of a dry battery to the primary output wire of the current transformer; then use the positive terminal of the dry battery to "click" the primary input wire of the current transformer, so that a + (positive) pulse current will be generated in the primary circuit of the transformer; at the same time, observe in which direction the needle of the pointer multimeter "deviations". If the needle of the multimeter deviates from 0 from left to right, that is, the needle is "positive start", indicating that the connected "primary input terminal of the current transformer" and "a certain output terminal of the secondary current transformer connected to the positive terminal of the pointer multimeter" are the same-named terminals, and this wiring is called "positive" or "subtractive"; if the needle of the multimeter deviates from 0 from right to left, that is, the needle is "reverse start", indicating that the connected "primary input terminal of the current transformer" and "a certain output terminal of the secondary current transformer connected to the positive terminal of the pointer multimeter" are not the same-named terminals, and this wiring is called "negative" or "additive".