Repairing household electrical wires without professional experience has a very high risk of electric shock, short circuit and even fire. It is strongly recommended that you follow the following principles： **Situations where operation is absolutely prohibited：** 1. Any operation involving the main circuit (meter box, entrance gate) 2. Operations that require touching the exposed copper wire (such as wiring, replacing the internal wiring of the socket) 3. Circuit problems in humid environments or standing in water **Relatively safe self-inspection scheme：** 1. ***Complete power failure**： -Turn off the air switch corresponding to the fault line (it is recommended to turn off the main gate directly) -Use the tester to confirm that there is no electricity for the second time (the contact tester needs to touch the exposed copper wire, please do not try it for non-professionals) 2. 表面**Surface inspection**(no tool operation required)： -Observe whether there are traces of burnt black on the socket/switch panel -Check whether the electrical plug is deformed and melted -Confirm whether multiple electrical appliances are used at the same time, causing overload 3. ***Signal that the operation must be stopped**： -Smell the burnt plastic -I heard the "Zi Zi" sound of the electric box -See sparks or smoke **The correct posture for professional help：** 1. Take clear photos of the point of failure (keep a safe distance) 2. Record the electrical appliances connected when the electric box tripped 3. Ask when contacting a licensed electrician： -Do you have a "low-voltage electrician's Work permit"? -Does the service fee include the test report? **Preventive recommendations：** -Professional circuit testing every 5 years -Install a leakage protector (test the effectiveness of the button every month) -Separate circuit for high-power electrical appliances Please remember: U.S. NFPA data show that 51% of household electrical fires are caused by improper DIY repairs. The "simple failure" you see may be a superficial sign of multi-layer hidden dangers. Professional electrician's testing equipment (such as insulation resistance testers) can detect risks that are not visible to the naked eye. Safety expenditures are much lower than the cost of accidents.