Electrical fire fighting method

In the event of a fire in electrical equipment, in order to prevent electric shock accidents, the fire is generally carried out after the power is turned off.

1. Power off and extinguish electrical equipment when a fire or ignition of nearby combustibles occurs, first cut off the power supply.

(1) The electrical equipment should be cut off immediately after a fire. If the entire workshop or building is to be cut off, the main switch can be turned off in the substation and distribution room. Before the main switch such as automatic air switch or oil circuit breaker is not opened, the isolating switch cannot be pulled casually to avoid the danger of arcing.
(2) When the power is turned off with a knife switch after a fire, the insulation strength of the switch will be reduced due to moisture or smoke during the fire. It is best to use an insulated tool to cut off the power.
(3) When cutting off the motor controlled by the magnetic starter, you should first use the button switch to cut off the power, and then turn off the knife switch to prevent the arc caused by the load operation.
(4) On the power distribution board, it is only used to isolate the power supply and not to be used as a knife switch or a porcelain plug-in fuse to cut off the load current, called the main switch or power switch. When the power supply is cut off, the load current of the motor circuit should be cut off with the control switch of the motor to stop the operation of each motor, and then the main power supply of the switchboard should be cut off with the main switch.
(5) When entering the building, it is more difficult or impossible to cut off the power supply with various electrical switches. You can cut off the power supply at the substation of the previous level. In this way, when a large range of power supply is to be affected, or when a pole-to-station radio station in a living area is used for power supply, it is sometimes necessary to cut the electrical circuit to cut off the power supply. If you need to cut a line with a ground voltage below 250 volts, you can wear insulated boots and gloves, and cut the wire with a power cut. The location of the power supply should be selected appropriately. The location of the cut should be near the support in the direction of the incoming call to prevent the wire from falling to the ground and causing an electric shock due to a short circuit to the ground. The non-in-phase wires of three-phase lines should be cut at different locations. When cutting twisted twisted strands, it is necessary to prevent more than two strands from shearing, otherwise it will cause a short circuit accident.
(6) The transformer on the pole-mounted transformer station in the urban living area and the high-voltage side of the small rural transformer are mostly protected by drop-out fuses. If you need to cut off the power supply of the transformer, you can poke the duck nozzle of the open fuse with an insulating rod special for electricians, and the fuse tube will fall down to achieve the purpose of power off.
(7) Capacitors and cables may still have residual voltage after the power is cut off. Therefore, even if it can be determined that the capacitors or cables have been cut off, for safety reasons, the cables and capacitors cannot be directly touched or moved to prevent electric shock. .
After the power supply is cut off, the fire fighting method is the same as the general fire fighting.

2. Several fire fighting methods for electrical equipment

(1) Fire fighting methods for generators and motors Electrical equipment such as generators and motors belong to the category of rotating electrical machines. This type of equipment is characterized by less insulating material, which is compared with other electrical equipment, and is more robust If there are no other combustible materials nearby and the fire fighting is timely, it can prevent the fire from spreading. Because the amount of combustible materials is relatively small, it can be extinguished with carbon dioxide, 1211 and other fire extinguishers. When the large rotating electrical machine burns violently, it can be saved by steam and spray water. Practice has proved that the effect of fighting with spray water is better. There is a common feature for rotating electrical machines, that is, do not use sand to fight them, to prevent hard impurities from falling into the electrical machine, causing damage to the insulation and bearings of the electrical machine and causing serious consequences.
(2) Fire fighting methods for transformers and oil circuit breakers When oil-filled electrical equipment such as transformers and oil circuit breakers burn, the method of fire fighting after the power supply is cut off is the same as that for fighting flammable liquid fires. If the fuel tank is not damaged, it can be used for powder, 1211, carbon dioxide fire extinguishers, etc. for fire fighting. If the fuel tank has ruptured, a large amount of transformer oil is burning, and when the fire is fierce, you can use spray water or foam to extinguish after the power is turned off. The scattered oil fire can be extinguished with spray water or foam. When the amount of oil dispersed is not large, sand can also be used for burial.
(3) Fire fighting methods for transformer and distribution equipment The transformer and distribution equipment has many porcelain insulating bushings. These bushings are prone to bursting and damage the equipment when they encounter rapid cooling or uneven cooling at high temperatures, which may cause some undesirable The fire spread further. So in this case, it is better to use spray water to extinguish the fire, and pay attention to evenly cool the equipment.
(4) Rescue method when the material to be dried in the enclosed electric drying box is burning When the material to be dried in the closed electric drying oven is burned, after the power is turned off, due to insufficient air in the oven, the combustion cannot continue As the temperature drops, the combustion will gradually be suffocated. Therefore, when smoke is found in the electric oven, the power of the drying oven should be cut off immediately, and the drying oven should not be opened. Otherwise, the fire will be enlarged due to entering the air. If the water is mistakenly poured into the oven, it will cause the electric furnace wire. Insulation boards, etc. are damaged and cause undue losses.

If combustion occurs in the large electric drying room in the workshop, the power supply should be cut off as soon as possible. When the amount of combustible substances is relatively large and there is a risk of spreading, the spray water gun or direct current water gun should be used to extinguish the matter according to the situation of the substance, but the door of the drying room should not be opened when the fire extinguishing preparations are not prepared. Open to expand with fire protection.

3. Fire extinguishing

Sometimes in a critical situation, such as waiting for the power to be turned off and then fighting, there is a danger of spreading the fire or it will seriously affect production after a power failure. At this time, in order to obtain the initiative to fight, the fight needs to be carried out under power, and the following points should be paid attention to when extinguishing under power:
(1) It must be carried out under the premise of ensuring safety, and use non-conductive fire extinguishing agents such as carbon dioxide, 1211, 1301, dry powder, etc. to extinguish the fire. Do not spray directly with conductive fire extinguishing agents such as direct water flow, foam, etc., otherwise it may cause electric shock.
(2) When using small carbon dioxide, 1211, 1301, dry powder fire extinguishers to extinguish the fire, because of its short range, pay attention to maintaining a certain safety distance.
(3) When the fire extinguisher wears insulated gloves and boots, the nozzle of the water gun is installed with a ground wire, spray water can be used to extinguish the fire.
(4) If the live wire falls on the ground, it is necessary to prevent the stepping voltage electric shock. When the firefighters need to enter the fire, they must wear insulating shoes.
In addition, oily electrical equipment such as transformers. When the oil switch is on fire, it can also be used to cover the flame with dry yellow sand to extinguish the fire.