How to measure the position of wires in a house?

The wires are all in a straight line. Generally, there are pvc pipes buried in the wall for indoor dark wires. The advantage of the hidden wire is that it is convenient to replace the wire. There should be a main line around the wall at the lower end of the roof, and then all lamps and sockets should be connected in parallel to the main line. Where there is a connector, there should be a junction box (such as where the lamp is connected to the main line). You can see if the connector inside the junction box is aging and wet, causing virtual connection. Please note that the junction box has a cover. If it is an early house, it may be built with iron. If you can't see it, it may be covered by the original owner when painting the wall. You can knock with your hands or tools directly above the switch of the light. If so, the junction box should be able to hear you. Right above, if not, you can knock. 10- 50 cm under the roof. If you can't find the line you want to change, you can find the local construction team. They all have water, electricity and heating installers. If you have a property, you can directly find the property. Other property companies may also take this kind of work. I really can't find the power department, and they may also take this kind of work. If it really doesn't work, rewire, cut off the original main power supply, cut a groove with a toothless saw and apply it to the pvc pipe, and then rewire. I don't know how big your house is. A standard room is about 400-600. It depends on the quantity and quality of the materials you use. The construction team is dry, you can ask about the decoration. It is best to buy your own materials. But you must repaint the walls.