Weak power grounding system construction program process
About weak power generally refers to the DC circuit or audio, video lines, network lines, telephone lines, DC voltage is generally within 36V. Below by me for you to organize the weak power grounding system construction plan process, welcome to read and browse.
1 Project Overview
** Phase I project, the construction area of about 59,500 square meters, two underground floors, 11 floors above ground. The structural form is frame shear wall, and the foundation form is raft plate foundation. North-south length of meters, east-west length of meters. In addition to the electric power supply and distribution system, there are building automatic control system, automatic fire alarm and linkage system, comprehensive network and communication system, cable broadcasting system, closed-circuit television monitoring system, security system (intrusion alarm system, access control system, patrol system), parking automation management system, cable television system, wireless signal access system, wireless intercom system, one card system, multi-function conference system, Master clock system, intelligent building management system, ACC network system, TCC network system, OCC network system and so on. The grounding system will directly affect the degree of automation and the use of the whole building function, the whole building grounding system using a comprehensive grounding method, all power systems, weak power systems, lightning protection system grounding are reliably connected to form a comprehensive grounding network, the use of equipotential grounding that is a point of grounding, the grounding resistance value of the requirements of the 0.5?
2 Preparation of the basis
2.1 Electrical installation construction and acceptance norms.
2.2 "Building Electrical General Drawing Book" (92DQ13).
2.3 "Building Electrical Installation Subprojects Construction Craft Standards".
3 construction preparation
3.1 Material Requirements:
3.1.1 Galvanized steel flat steel, angle steel, round steel, steel pipe, etc., when used should be intended to use the cold galvanized or hot-dip galvanized material, should be consistent with the design provisions. The product should be material inspection certificate and product certification.
3.1.2 Galvanized auxiliary materials are lead wire (i.e. galvanized iron wire), bolts, washers, spring washers, U-bolts, bolts, brackets and so on.
3.1.3 Welding rods, oxygen, acetylene, bituminous paint, concrete brackets, pre-embedded iron parts, small wires, cement, sand, plastic pipes, red paint, white paint, anticorrosive paint, silver powder, black paint and so on.
3.2 Main machines and tools:
3.2.1 Commonly used electrician's tools, hand hammers, steel hacksaws, saws, pressure cases, shovels, pickaxes, sledgehammers, tamping buckets.
3.2.2 Line pendant, tape measure, large rope, powder line bag, winch (or inverted chain), tighten the line, electric hammer, impact drill, welding machine, welding tools and so on.
3.3 Construction schedule. Because the sub-projects throughout the construction process, so the construction schedule with the civil construction, not another arrangement.
3.4 Labor force plan. 10 electricians, 2 gas welders, 2 erectors, 1 manager.
4 Construction process and method
4.1 Construction method of ring grounding body. The use of structural base plate reinforcement up and down the two layers of each of the two ?25 rebar welded into a pressure-even ring, and welded into a grid no larger than 20 * 20 meters, the entire base steel connected to the electrical path as the grounding network of this building.
4.2 Lightning protection device construction method
The lightning protection level of this project for the second category, the building lightning protection device to meet the direct lightning, side-strike lightning, lightning induction and lightning wave intrusion, and set the total equipotential linkage.
4.2.1 Flashover. On the roof using ?10 galvanized round steel for 10 * 10 m lightning belt grid.
4.2.2 Lead wire. The use of structural columns within the two ?25 rebar for lightning protection lead wire, the distribution of which is shown in the figure below. Lead down the main bar up and down the connection, with ?12 round steel to do excessive jumper, double-sided welding, welding length of more than 100mm. lead down the upper end of the line and the lightning belt welding, the lower end of the grounding ring with the building foundation beams up and down the two layers of the grounding ring network welded, welded length of more than 100mm.
In the four corners of the building's exterior wall lightning protection lead line from the ground 500mm to set up a special test box, special grounding box through the -40 * 4.5mm, the grounding box is a special test box, the special grounding box. Grounding box through the -40 * 4 galvanized flat steel and grounding lead main bar connection, flat steel and the main bar using three-sided welding, welding length of more than 80mm. flat steel and grounding test box terminal copper row with two M10 bolts connected to the copper row on the installation of ?999?-type terminal, as a grounding test connection.
4.2.2 The roof lightning net is welded together with all the steel structures of the building that protrude from the roof. Non-metallic buildings outside the protection range of the roof flasher, should be installed flasher, flasher and the roof of the lightning belt welded together. Roof lightning belt while protecting the solar panel, in the distance from the solar panel plate surface of about 400mm-1000mm above the use of ?10 galvanized round steel laying lightning grid, selecting the spacing gap between the panels, the installation of brackets fixed to the solar panels on the channel, and do a good job of the welding points of the anticorrosion treatment, at the same time, and the roof lightning protection system is firmly welded together with lightning protection belt.
4.3 Equipotential grounding bus. This project adopts the equipotential grounding connection, the total equipotential box MEB is set in the substation mezzanine from the floor at 0.5 meters. The total equipotential bonding box leads to two -40 * 4 galvanized flat steel and the building ring grounding network base bar welding. Three-side welding, welding length is more than 200mm. 60 sets of M14*35 copper bolts are installed in the general equipotential junction box, lightning grounding, protection grounding, EMC grounding, anti-static grounding, transformer neutral grounding, PE grounding, weak system grounding, ACC system grounding, TCC system grounding, OCC system grounding are all led from the general equipotential junction box to form a one-point grounding to eliminate potential difference between the system grounding. The potential difference between the system grounding to meet the requirements of electromagnetic compatibility.
4.4 Grounding construction method of the power system. 10KV substation set up a grounding terminal box, which leads to 12 YJV-1*240 cable as the neutral ground of each transformer and the PE ground of each power distribution cabinet. Substation around 500mm from the ground with -40 * 4 galvanized flat steel welding a ring grounding network, as the distribution cabinet (control panel, console) of the basic channel steel grounding, distribution cabinet (control panel, console) shell grounding, various bracket grounding, bridge grounding, cable protection layer grounding, grounding switch grounding and test grounding. Substation grounding system using TN-S grounding system.
4.5 Equipotential connection construction method
4.5.1 Equipotential connection of various pipelines. All the equipment in and out of the building metal pipe skin and grounding protection line through the grounding terminal box connected into one, equipotential connection trunk using YJV-1 * 25 cable through the PVC32 pipe for protection. In the outer skin of the metal pipe using -40 * 4 galvanized flat steel made of hoop for fixing, with M10 galvanized bolts, BV-25 plastic copper wire crimp noses, plus metal flat pads, spring pads fixed to the M10 bolts.
4.5.2 Glass curtain wall equipotential connection. Fixed in the whole building of 3, 8, 10 layers of columns on the glass curtain wall of the embedded parts, with ?12 round steel welded to the main bar of the lightning lead, three-sided welding, welding length greater than 80mm, columns do not have lightning lead, through the layer of the ring beam main bar and lightning lead columns with the main bar welded together.
4.5.3 Antistatic ground equipotential connection. All rooms with antistatic ground, in the structure of the floor on the main steel with -40 * 4 galvanized flat steel lead out of the ground, flat steel and the main steel welded with three-sided welding, welding length greater than 80mm, welding the main bar to form an electrical path with the layer of lightning lead, as the equipotential connection point in the refurbishment.
4.5.4 Bathroom equipotential connection. Set up an equipotential connection box in the bathroom, and the equipotential connection trunk line adopts YJV-1*25 cable wearing PVC32 pipe for protection. All metal pipes and metal parts in the bathroom are connected to the equipotential connection box by -BV4 plastic copper wire, -BV4 plastic copper wire is protected by PVC16 pipe.
4.6 Electrical small indirect grounding construction method
4.6.1 Strong electrical small indirect grounding using -40 * 4 galvanized flat steel for grounding trunk, strong electrical shaft of galvanized flat steel and the building's grounding trunk welded together. In the galvanized flat steel of the electrical cubicle welded M10 bolts, as distribution boxes (cabinets), cable bridges, closed bus and other pipe shell grounding.
4.6.2 Equipotential junction box is set up for each weak electricity cubicle, the trunk of equipotential junction box adopts YJV-1*25 cable to connect with the general equipotential junction box on the first floor, and leads to the weak electricity shaft through cable bridge, and then adopts PVC32 pipe to lay to the weak electricity cubicles on each floor. Equipotential junction box set 20 equipotential grounding terminals, as the weak power system in each layer grounding.
4.7 Weak-electricity system grounding construction method. All of the weak power system room are using one point grounding method. In the room set up a special grounding box, grounding box trunk line using YJV-1 * 25 cable and the first floor of the general equipotential junction box connection, through the cable bridge laying led to the weak power equipment room, and then use PVC32 pipe dark laying to the grounding box location. Equipotential junction box set 20 equipotential grounding terminals, as the weak power equipment room grounding.
4.8 ACC system grounding construction methods, ACC system using one-point grounding, in the ACC system power supply room set up equipotential junction box, equipotential junction box trunking 2 YJV-1 * 25 cable and the first floor of the total equipotential junction box connection, through the cable bridge laying to the power supply room of the ACC system, equipotential junction box set up 20 equipotential grounding terminal, as the ACC system grounding. As the ACC system grounding.
4.9 TCC system grounding construction method, TCC system adopts one-point grounding method, TCC system power supply room with equipotential junction box, equipotential junction box. Trunk using two YJV-1 * 25 cable and the first floor general equipotential junction box connection, through the cable bridge laying lead to the TCC system power room, equipotential junction box set 20 equipotential grounding terminals, as the TCC system grounding.
4.10 OCC system grounding construction method: OCC system adopts one-point grounding method, OCC system power supply room is equipped with equipotential junction box, equipotential junction box trunk line adopts 2 YJV-1*25 cables to connect with the general equipotential junction box in the first basement level and leads to the power supply room of the OCC system through cable bridge laying, equipotential junction box is equipped with 20 equipotential grounding terminals as the grounding for OCC system. As the OCC system grounding.
5 quality standards
5.1 Main control items:
5.1.1 The quality of materials meets the design requirements; grounding resistance of the grounding device must be in accordance with the design requirements.
5.1.2 The branch line connected to the grounding of electrical equipment, appliances and other non-electrically charged metal parts that can be removed must be directly connected to the grounding trunk, and series connection is strictly prohibited.
Inspection methods: actual measurement or check the grounding resistance test records. Observation check or check the installation records.
5.2 General items:
5.2.1 Lightning rod (net) and its supporting parts installed in the correct location, fixed firmly, good corrosion; vertical outer body, lightning net specifications size and bending radius is correct; lightning rod and supporting parts of the production quality in line with design requirements. Lightning rod with a sign lamp lamps and lanterns complete, clear display. Lightning net support spacing is uniform; lightning rod vertical deviation is not greater than the diameter of the top outer rod.
Inspection method: observation and inspection and actual measurement or check the installation records.
5.2.2 Ground wire laying:
5.2.2.1 Flat and straight, firm, even spacing of fixing points, compensating device across the deformation joints of the building, protection pipe through the wall, and complete painting and anticorrosion.
5.2.2.2 Welded joints are flat and full, with no obvious defects such as air holes and biting meat; bolts are tightly and firmly connected, and there are anti-loosening measures.
5.2.2.3 Lightning grounding lead wire jumper welding length to meet the requirements of the acceptance specification.
Inspection method: observation and inspection.
5.2.3 Ring grounding body installation:
Correct position, solid connection. Records of concealed works are complete and accurate.
Inspection method: check the hidden engineering records.
5.3 Allowable deviation items:
5.3.1 Lap length?2b; round steel?6D; round steel and flat steel?6D;
Note: b is the width of flat steel; D is the diameter of round steel.
5.3.2 Flat steel lap welding 3 prongs, round steel welding double-sided.
Inspection method: ruler check and observation check.
6 Quality issues to be noted
6.1 Ring grounding body:
6.1.1 Ring grounding body must be connected to an electrical pathway, and no welding shall be omitted, according to the design requirements.
6.1.2 Welding surface is not enough, flux skin treatment is not clean, anti-corrosion treatment is not good, the welding surface is corrected according to the quality requirements, the flux skin will be knocked clean, good anti-corrosion treatment.
6.1.3 The use of foundation, beam and column reinforcement lap area is not enough, should be strictly according to the quality requirements to do.
6.2 Bracket installation:
6.2.1 Loose bracket, concrete support is not stable. Find out the cause of loose bracket and then fix it firmly; put the concrete support smoothly.
6.2.2 The spacing of the bracket (or embedded iron) spacing is not uniform, straight section is not straight, beyond the allowable deviation. Re-modify the spacing, the straight line section is corrected and straight, not exceeding the allowable deviation.
6.2.3 Welded joints have slag, bite meat, cracks, pores and other defects. Re-welding, the above defects are not allowed to appear.
6.2.4 Welding flux skin treatment is not clean, leakage of antirust paint. Should be welded at the flux skin treatment clean, make up the brush anti-rust paint.
6.3 Lightning lead wire dark laying in the column
6.3.1 Welding surface is not enough, welded joints have slag, bite meat, cracks, pores and flux skin treatment is not clean and other phenomena. It should be repaired and changed according to the specification requirements.
6.3.2 Leakage of antirust paint, should be made up in time.
6.3.3 Lead position of the main bar, should be corrected in time.
6.3.4 Lead wire is not vertical, exceeding the allowable deviation. The lead wire should be horizontal and vertical, and the exceeding deviation should be corrected in time.
6.4 Lightning net laying
6.4.1 Welding surface is not enough, the welded joints have slag, bite meat, cracks, pores and flux skin treatment is not clean and other phenomena. It should be repaired and changed according to the specification requirements.
6.4.2 Antirust paint is not uniform or there is a leakage of the brush, should be brushed evenly, the leakage of the brush to make up.
6.4.3 Lightning cable is not straight, beyond the permissible deviation, after adjustment should be horizontal and vertical, shall not exceed the permissible deviation.
6.4.4 Loose card screws, the screws should be tightened in time.
6.4.5 Compensation treatment is not done at the deformation joints, it should be made up.
6.5 Lightning belt and pressure equalizing ring
6.5.1 Welding surface is not enough, the welded joints have slag, bite meat, cracks, pores, etc., should be repaired and changed in accordance with the specification requirements.
6.5.2 Glass curtain wall, iron railing grounding lead missing, should be made up in time.
6.5.3 The joints of the ring beam are not welded, and should be made up.
6.6 flashover (lightning rod) production and installation
6.6.1 Welding is not full, flux treatment is not clean, missed brush rust paint. Should be timely to make up the welding, the flux skin knocked clean, brush on the anti-rust paint.
6.6.2 Needle body bending, installation of verticality beyond the allowable deviation. The needle body should be re-straightened to meet the requirements before installation.
6.7 Grounding trunk installation
6.7.1 Flat steel is not straight, should be re-straightened.
6.7.2 Grounding terminal missing pad spring pad, should be made up in time.
6.7.3 Welded joints have slag, bite meat, cracks, pores and flux skin treatment is not clean and other phenomena. Should be in accordance with the specification requirements for repair and change.
6.8 Leakage of antirust paint, should be made up in time.
7 quality records
7.1 Galvanized flat steel or round steel material certificate and factory certificate.
7.2 Lightning protection and grounding construction pre-inspection, self-inspection, hidden inspection records are complete.
7.3 Design change negotiation records, as-built drawings.
7.4 Lightning protection and grounding sub-project quality inspection and assessment records.
8 safety and fire safety measures
8.1 All construction personnel entering the construction site must wear helmets and insulated shoes. 2 meters above the height of the work, you must fasten the safety belt. When working on scaffolding, the ends of the probe plate must be fixed firmly. Ladder work should be guarded and have reliable anti-skid measures.
8.2 site construction is strictly prohibited smoking, a variety of oil, paint should be stacked in accordance with the provisions of the place, set up a person to look after.
8.3 Electrically charged operations, need more than two people to carry out, wear insulated shoes, to prevent electrocution, and have all the safety equipment.
8.4 When using mechanical drilling, it is strictly prohibited to operate with gloves or hand-held workpiece to operate. The tertiary power distribution box and hand-held power tools, insulation checks should be carried out frequently.
8.5 The use of open fire should apply for open fire procedures and fire certificate, in the fire site should pay attention to the surrounding environment, away from flammable materials, and equipped with the necessary fire extinguishing equipment, fire should be cleaned up the scene to eliminate potential hazards.
8.6 Storage, use of welding, oxygen and acetylene, should be centralized according to the provisions of the management, and must be equipped with fire extinguishing equipment. When using welding, the handle wire, ground wire should be double line in place, shall not use metal components as ground, and operate in accordance with the provisions.
8.7 When working on the roof, pay attention to the protection of finished products, it is strictly prohibited to step on the collapse of the roof, it is strictly prohibited to use the electric drill to drill holes in the roof at will, welding operations should be padded below the rock surface for protection.
8.8 When working on the metal roof, pay attention to the protection of the metal keel, after welding, to brush the anti-rust paint twice to prevent rust.
9 Environmental protection and civilized construction
9.1 Construction workers are not allowed to drink during the construction site.
9.2 The construction site should be clear after the work.
9.3 The use of equipment to maintain the machine in good condition, machine appearance neat and tidy.
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