Electrician's network access certificate is issued by the local electric power bureau, and they organize training. After passing the exam, prove that you are qualified to work in the power grid. There are high pressure and low pressure. Above 500V is considered as high voltage, below 500V as low voltage. High-voltage certificate can work under low voltage, on the contrary, low voltage cannot work under high voltage. You can apply to the Electric Power Bureau for research, and there are training courses every month for several hundred yuan. The content is the basic knowledge of electrician, electrotechnics and so on.