Safety ladders are mainly emergency measures for underground operators to get up in case of sudden power failure.
three-phase five wire system) must be adopted in the low-voltage power line with direct neutral grounding dedicated to the construction site; The protective zero line shall be led out from the working grounding or the zero line in the distribution room or the zero line at the power side of the first level leakage protector; The protective zero line shall be laid separately from the working grounding wire and shall not be used for other purposes.
The first section of the retaining wall of the hole pile shall be 20cm higher than the ground of the opening as a safety skirting fence around the orifice.
Each downhole operation must be carried out after 15 minutes of ventilation.
When the overhead laying spacing is greater than 12 meters, the cross-section of the insulated copper wire shall not be less than 10mm2; Insulated stranded copper wire with a cross-section of the protective zero line connected to the electrical equipment of not less than 2.5mm2; Under normal conditions, metal enclosures, frames, components, pipelines, tracks, metal operation desks, metal fences and metal doors close to live parts of electrical equipment shall be connected to neutral for protection; The direct working grounding resistance of the neutral point of the power supply transformer should be less than 4 ohms, and the repeated grounding resistance of the protective zero line should be less than 10 ohms; Some electrical equipment shall not be used for protective neutral connection and some for protective grounding.
In general, the rated leakage action current of the leakage protector should not be greater than 30mA, and the rated action time should not be greater than 0.1s; In wet and corrosive places, the rated leakage action current shall not be greater than 15mA, and the rated action time shall not be greater than 0.1s; The limit of the product of rated leakage action current and rated action time is (not more than) 30ma s； The selection of leakage protector in the switch box should be compatible with the actual situation such as the capacity and number of phases of the power equipment.
The blower supplies air to the underground through the air duct.
Scaffolding Adjustable Base Jack Nut
Sundries shall not be stacked within 2m of the orifice, and protective barriers shall be set around the wellhead to prevent sundries from falling.
During cage operation and inspection, sit on the safety cage and go up and down the well.
The lighting voltage in the hole shall not be higher than the safety voltage of 12V.
Toxic gas detector for piles over 4m, operators need to put the instrument down for detection before going down the well for the first time every day.
All wires of the distribution system must be erected with special poles, insulators, cross arms, etc.
The minimum vertical distance between the motorway on the construction site and the external power overhead line is 6 meters below 1kV and 7 meters between 1kV and 10kV.
The bucket shall be stable and vertical up and down, and the operators shall stand under the safety shield.
The setting of distribution switch box, distribution box and switch box shall comply with the principle of “three-level distribution two pole protection”.
in the workers’ dormitory, and it is not allowed to generate kindling randomly; Electrical devices should be overhauled regularly..
according to the specification requirements; Switchgear and electrical devices must be intact; Switching appliances and electrical devices must be installed correctly and firmly, and shall not be placed on the ground; The joints between live wires must be insulated and wrapped, and live wires must be well insulated; Live conductors shall not be erected, hung or pressed on scaffolds or other objects; The distribution box and switch box shall be marked with name, purpose and shunt; The distribution box and switch box shall be equipped with locks and be in the charge of a specially assigned person; There shall be no sundries in and around the electrical device; It is strictly forbidden to use fancy wires, copper wires or other metal wires instead of fuses for power use at the construction site.
The minimum safe operating distance between the outer edge of the external power protection project under construction (including scaffolding) and the edge of the external power overhead line and the minimum safe operating distance: 4 meters for voltages below 1kV and 6 meters for voltages between 1kV and 10kV.
The protective zero line PE must use yellow / green double color lines; The protective zero line must be repeatedly grounded at least three places in the middle and end of the distribution line in the distribution room (or general distribution box), and the repeated grounding wire should be connected with the protective zero line; The cross-section of the protective zero line shall not be less than that of the working zero line, and must meet the mechanical strength requirements.
Non operators are not allowed to enter the guardrails.
Safety belt ground construction personnel must wear safety belts when working at the wellhead to prevent falling.
（3） The TN-S neutral protection system (i.e.
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During construction, fresh air is continuously delivered to the hole, and construction air supply is carried out at the same time when necessary.
（2） For ventilation and gas prevention, the drainage and air supply shall be carried out first in the hole digging operation.
During lifting, the bucket shall not be full to prevent overflow.
When the bucket digging pile is less than 5 meters, the reinforcement shield net shall be set in the territory, and the upper two meters of the hanging and operating personnel shall be lowered with the excavation depth.
Steel pipe guardrails are set around the slope top of the foundation pit, with a height of 1.2 meters.
For example, three-phase leakage protector with matching parameters should be selected for three-phase motor; The power for lighting must be separated from that for power, and the single-phase two-wire leakage protector should be selected for lighting.
Adhere to the operation principle of sending air first and then sending people down to prevent toxic and harmful gases such as CO and methane.
The switch box shall not be more than 3 meters away from the machines and tools, and the switch box shall be protected by “one machine, one brake, one leakage and one box”.
During the vertical transportation of meniscus, prevent the muck in the bucket from falling.
Three-level distribution refers to the main distribution box – distribution box – switch box – electrical equipment; Two pole protection refers to the protection of zero line and leakage protector.
At the same time, the toxic gas detector constantly monitors whether there is toxic gas in the well.
The distribution box and switch box at the construction site of leakage protector shall be equipped with at least two-level leakage protector; The leakage protector should be current operated.
The gas mask is used for rescue in case of sudden power failure, harmful gas or other emergencies.
It is strictly forbidden to pull wires, sockets, electric furnaces, rice cookers, etc.
