Does the switch panel generally have no zero line?

Whether the switch panel needs a zero line depends on this switch, such as an intelligent switch or a switch with an indicator light. It needs a zero line and the rest don't. The switch panel in the figure doesn't need to be connected to the zero line, but the red line of the tape wrapped in the junction box in the figure should be the zero line, so the switch in the figure can be changed to a single switch socket, and the switch is a double control switch, as shown in the figure. Just lead a live wire from the switch (which one is red on the switch panel) to the live wire of the socket, and the zero wire leads a wire from the wrapped tape to the zero wire of the socket. Over.