Fire protection requirements for electrical circui

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Fire protection requirements for electrical circuits in special places

particularly damp houses refer to bathrooms, kitchens, laundry rooms, and places emitting water vapor

the insulation performance will be reduced, even damaged, and short circuit will occur if the insulated conductor is damped. The main reasons are: (1) improper selection of conductor specification and model; (2) Unreasonable conductor laying method, etc

the electrical circuit laying in this place shall meet the following requirements:

(I) the circuit laying shall try to use insulated conductors to pass through PVC fire-proof rigid plastic pipes or steel pipes. The steel pipe must undergo rust prevention treatment, and the pipe orifice shall be subject to corresponding waterproof treatment. Porcelain insulator open wire can also be used for laying. Insulated conductors with protective layers, such as lead wires and plastic sheathed wires, can also be used

(II) precautions the insulation and withstand voltage strength of the conductor must meet the line voltage requirements, and shall not be less than 500 V when passing through the pipe

(III) when checking and maintaining the electrical circuit, attention must be paid to power-off inspection, testing the insulation resistance and removing the dust on the wire surface. Especially before the mildew and rain season, cleaning must be carried out

II. High temperature house

high temperature house refers to heat treatment workshop, drying room, high temperature aging room, etc. Due to the high ambient temperature, the safe current carrying capacity of the conductor is greatly reduced, which is easy to cause conductor overload. At the same time, the heat of the wire is not easy to emit, and the insulation is easy to be aged and damaged. Therefore, when wiring in high-temperature houses, the temperature of the surrounding environment should also be considered to meet the following requirements:

(I) after the wire section is determined according to the safe carrying capacity, the line must be corrected according to the highest actual ambient temperature throughout the year. It shall be laid as far away from heating zone such as heating furnace as possible. Copper core glass braided rubber wire should be used as the conductor connecting the heater, and asbestos sleeve or PVC fire-proof hard plastic pipe should be used outside the wire for protection

(II) precautions: the conductors laid in high-temperature houses are prone to aging, so the insulation strength of the conductors must be regularly checked and tested

III. dusty houses

dusty houses generally refer to workshops and plants with a large amount of dust, such as textile factories, cement factories, flour factories and pencil factories. If there is conductive powder, the risk is greater. On the 4th, the national billet market became stronger. The metal powder is suspended in the space and is easy to accumulate on the surface of the conductor. If the insulation of the conductor is damaged and the live wire core is exposed, the current will leak through these powders. Without damaging the sample and zigzag auxiliary parts, it will cause short circuit to ground or phase to phase short circuit and cause combustion

(I) the wire shall be laid through the pipe in an open or concealed manner. The end of the electric conduit shall be sealed with asphalt. Dust prevention measures shall be taken for the electrical equipment. The lamp cap box, hanging box, lamp cap and the junction box of the motor shall be sealed, and the accumulated dust in the house shall be removed frequently

(II) precautions electrical appliances in dust environment with fire and explosion hazards shall be installed with explosion-proof electrical appliances

IV. houses with corrosive gas

houses with corrosive gases refer to houses with acidic, alkaline and other corrosive gases, such as electrolysis room, electroplating room, etc. Acid and alkali are good conductive media, which can corrode the vast majority of wires. 6. Specific operation steps of all experiments: edge, causing accidents

(I) the line shall be laid in PVC fire-proof hard plastic pipe with insulated wires laid in open and dark, and the equipped pipeline accessories shall be made of plastic. If steel pipes are used for laying, they shall be subject to anti-corrosion treatment. If the current flow is large, when copper and aluminum wires are exposed, they shall be fixed with porcelain bottles and protected with anti-corrosion paint

(II) precautions corrosive gas can oxidize the contact surface of electrical equipment, resulting in high contact resistance and overheating of the contact. In serious cases, it can ignite nearby combustibles. Therefore, it is necessary to "anlimu" to always eliminate the oxide on the contact surface, and the electrode contact on the electroplating bath should be cleaned at any time to ensure good contact

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