There are three reasons for electric shocks caused by electricians during maintenance:
Electric shock circuit between two wires: When two different parts of the body of the maintenance person touch the bare parts of two wires or the two terminals at the same time At that time, the human body will connect the circuit between the two wires to form an electric shock loop.
If it touches two phase wires of a low-voltage line, the human body bears a line voltage of 380V; if the human body touches a phase wire and a neutral wire, then the human body bears 220V Phase voltage.
The electric shock circuit of the human body intervention circuit: When the electrician is checking and repairing the single-wire control switch, the wire connection point or the fuse, if the human body touches two terminals or two disconnected wires at the same time, once the circuit is electrified, then The human body will be chained into the loop.
Electric shock circuit between line and ground: When the body of the inspector touches a live line and a conductive wall pillar, ground, water pipe, etc. at the same time, the current will flow through the human body, the building and the ground to form a loop. The human body may also withstand a voltage of 220V, and the current value flowing through the human body is also a serious threat to life.
Therefore, in order to prevent the occurrence of the above three situations, electricians must strictly implement the following safety operation principles during maintenance work!
Single-line operation: during maintenance work, the human body is at all times Two wire ends, two contacts, or two wiring terminals cannot be touched separately. One wire end and one wire end must be processed. If there are nearby live bare wires that are accidentally touched, they must be shielded in advance.
Isolation from the earth: During maintenance work, all parts of the human body must be reliably insulated from the earth. Therefore, electricians must wear electrician insulated shoes, tools with insulated handles, protective work clothes, and dry ladders with bamboo or wooden structures in strict accordance with safety work regulations. If you don’t climb high, Xiaohui suggests that you can use a dry wooden board and other insulation to pad it underneath. At the same time, the human body cannot touch the building during operation. Moreover, when receiving tools or parts from persons who are not isolated from the earth, the maintenance personnel must stop the operation, and their hands must be separated from the maintenance point. Only in this way can we avoid the formation of an electric shock circuit between the line and the ground.
Breaking the current circuit: When inspecting and repairing individual circuits of electrical appliances, the closed circuit that may be formed by the circuit must first be eliminated. If the light switch is overhauled, the bulb must be removed first. In this way, even if the human body touches the two connection terminals of the switch at the same time, it will not form a closed loop due to human body intervention. Or when replacing the entire fuse on the switchboard, you must first unplug the power plug of the mobile electrical appliance. In this way, even if your hands touch the upper and lower connecting wires at the same time, it will not be closed due to human intervention. Loop. In addition, when the electrician is overhauling the wire box or the lamp holder, the light switch must be disconnected first. This method can avoid the electric shock loop formed when the two terminals are touched at the same time.