Thursday, December 1, 2016

Laying technology for flexible metal conduit

1 scope
This technology is applicable to general industry, civil construction engineering 1kV and below lighting, power, weak flexible metal conduit and dark laying and the ceiling and wall panels in the flexible metal conduit (plica tube) work.
2 construction preparation
2.1 materials requirements:
2.1.1 flexible metal conduit and its annex shall comply with the relevant provisions of the existing national technical standards and certification. Also should have the local fire department to produce flame-resistant proof.
2.1.2 flexible metal conduit wiring project with clamp, brackets, hangers, fittings and boxes, boxes and other accessories shall be galvanized or coated with paint.
2.1.3 flexible metal conduit and related accessories specifications shall conform to the national standard requirements and design requirements.
2.1.4 other by needed material: wire pipe, and wiring box, and lamp box, and socket box, and distribution box, and wiring box connection device, and mixed tube joint, and lock tight nut, and fixed clip, and grounding clip, and round, and flat steel, and angle, and bracket, and hanging rod, and bolt, and nut, and washer, and spring washer, and expansion bolt, and wood screws, and since attack screws, metal parts are should plating zinc processing or for rust processing.
2.2 the main tools:
2.2.1 flexible metal wire and pipe cutters, hydraulic opening, toothless saw, bench drill, hand drill, hammer, electric welding machines, nail guns.
2.2.2 live moving hands, hacksaw, fish pliers, hammer, chisel, cabinet file, drills, pliers, screwdrivers, electric knives.
2.2.3 horizontal ruler, set square, ruler, pencil, line, Gray Ash bucket, shovel, pink bags.
2.3 operating conditions:
2.3.1 pipe laying:
2.3.1.1 fit dark concrete structure when laid, according to the design drawings, in front of the reinforcement as finish, concrete water pipe stable boxes, buried under the reservation box, bin location.
When pipeline construction brick-dark paid 2.3.1.2, wall standpipe, installation and location boxes, cartons, boxes, or reserved.
2.3.1.3 serve light ceiling or wall surface laying pipe, according to construction detail drawing, first line make sure lights, sockets and other locations, with the ceiling and the wall piping, steady the keel box, box.
2.3.1.4 the ceiling using a separate support, hanging the concealed piping, piping in the ceiling joist installation box.
2.3.2 out pipe laying:
2.3.2.1 should be installed during structural embedded parts, reserved holes and caves.
2.3.2.2 using embedded method of fixation and should be completed prior to plastering; when using expansion bolts fixing bracket, should be carried out after the plastering.
2.3.2.3 plumbing steady spray of box should be in civil decoration.
3 operational processes
3.3 piping installation requirements:
3.3.1 should according to the design drawings to determine pipe direction, pipe laying. And should reduce bending, reaching towards a reasonable, easy maintenance overhaul.
3.3.2 should be laid according to the location, environmental conditions, the correct choice of flexible metal wire and tube specifications and accessories.
3.4 dark pipe laying:
3.4.1 box, box location: according to the axis of the construction drawings to determine cases, boxes, pop-up horizontal, axis is civil as a benchmark, hang level, fall line alignment, standard out of the box, the box of the actual location. Rows, the rows of boxes, boxes should be telephoned or cross lines.
3.4.2 concealed in concrete structure in the pipeline, the pipeline should be laid in the midst of two layers of steel. Vertical line no vertical reinforcement laying on the same side, horizontal pipe should be laid along with lateral transverse reinforcement.
3.4.3 when the brick-concrete structure wall concealed, manage and shall promptly block the nozzle, and tube along with the provisional pole installation direction lever.
3.4.4 prefabricated dark laying on the floor, should be looking for lamp note box tubing. Immediately after laying the pipeline with the strength of cement mortar not less than C10 stability protection.
3.4.5 tick Groove installation should be in slots on both sides of the first line, with cold chisel tick Groove width and groove depth to 5mm larger than the pipe diameter is appropriate. Aerated concrete wall should be electric blade slot. Tick tank installation, rejection of Tenon-is strictly prohibited.
3.5 is concealed within the ceiling, pipes can be laid in the main keel. Separate hanging pipe, its hanging point should not exceed 1000mm. Boxes, boxes on either side of the fixed line, should not be greater than 300mm.
3.6 wall panels (light gypsum board partition) is concealed within, should be established for the keel at the same time. Its fixed line, flexible metal wire tube matching clips can be fixed.
3.7 entering the box line, should be neat, BG/UBG type junction box connector box lock, and installed BP insulation protection. When entering the ground-mounted distribution boxes, screens, flexible metal conduit, in addition to distribution box Foundation not less than 50mm per cent higher, also makes pipe fixation.
3.8 fixed line:
3.8.1 installation in reinforced concrete pipe, and reinforcement should be firm, lashing of the pipe spacing should not be greater than 500mm, lashing from the box, the box should not be greater than 300mm. Binding thread thin wire can be used.
3.8.2 brick or masonry wall tick channel laying pipe at intervals not greater than 1000mm distance, with a fine wire, Iron nails.
3.8.3 ceiling and wall panels in the pipeline, at intervals not greater than 1000mm distance, fixed by special clips. In junction box, box joints, fixed point value should not be greater than 300mm.
3.8.4 the prefab (round hole) on the pipe, use plate fixed with nails, wire and mortar protection.
3.9 connection:
3.9.1 flexible metal pipe connected with a flexible metal conduit and wires and steel pipe, thick metal pipes and wires, various types of joins of boxes, shall be made in the special attachments. As shown in table 3-12.
Types of flexible metal conduit fittings and use table 3-12
Types and models
BG junction box connector flexible metal conduit and junction box connections
UBG combination junction box connector combination of flexible metal conduit and junction box connections
Hybrid connectors KG flexible metal wire tube and steel wire and pipe connections
VKC Threadless connectors, flexible metal wire tube and steel wire and tube combination
UKG mix Connector connection
Direct connector between KS flexible metal conduit connect
Insulated sheathing BP to protect wire insulation from damage, installed at the end of flexible metal conduit
Clip SP fix flexible metal conduit
Angle-AG flexible metal conduit junction box connector connected with the junction box right angle combination
Waterproof junction box connector WBG outer PVC plastic combination of flexible metal conduit and junction box connections
Waterproof hybrid connectors WCG covered with flexible metal conduit PVC plastic and steel wire combination of sheathed protecting pipe connection
WAG angle-waterproof junction box connector flexible metal wire covered with PVC plastic tube connected to the junction box right angle combinations, such as
Earth clamp DXA fixed ground wire

3.9.2 flexible metal conduit and boxes except when using special accessories outer, should also be done: box hole neat, Aperture coincides with the pipe diameter, tube hole must not be longer holes, electrical welding holes in iron boxes is prohibited.
3.9.3 flexible metal conduit with flexible metal pipe coupling with KS series connectors and wires. Due to the threaded pipes, connectors, hand tighten screwed directly into the tube.
3.10 as VKV series threaded connector with tube connections, must be using a wrench or pliers to tighten the connector screws to prevent loose when pouring concrete.
3.11 pipe cutting methods:
3.11.1 flexible metal tubes and wires cut, should be carried out using special cutters, and can be cut with an ordinary hacksaw.
3.11.2 hold flexible metal conduit or placed in the bench press with your hands, the blade perpendicular to the axial alignment ripple pipe, side edges cut off tube.
Section 3.11.3: pipe cut off, can be connected directly to the connector. But for convenience and accessory connection can back out Burr, to smooth the section. C with a knife on the inside rotating twisted around, make it easier to cross the line.
3.12 ground connection:
3.12.1 flexible metal pipes and tubes, boxes and other connections and wires, must be used to connect flexible metal wire tube matching grounding clip, the grounding jumper section of not less than 4mm2 copper wire. Flexible metal conduit shall not be used for fusion welding connect the ground wire.
3.12.2 flexible metal conduit, box, boxes should join one reliable grounding.
3.12.3 flexible metal conduit shall not be used as an electrical ground wire. AC 50V DC piping not bridging grounded 120V and below.
3.13 when the flexible metal conduit underground, and the bending radius should not be less than 6 times times the outer diameter.
3.14 concealed in pipes in the buildings, structures and buildings, minimum layer on the surface of the structure should not be less than 15mm.
3.15 when concealed, flexible metal conduit may be subject to heavy pressure or apparent mechanical impact, effective protection measures should be taken.
3.16 flexible metal conduit through the buildings and structures of settlement joint or joints, compensation measures should be taken, wire should be enough.
3.17 when the flexible metal conduit when you encounter one of the following, you should set the junction box or cable box.
3.17.1 tube longer than 30m, no bending;
3.17.2 tube longer than 20m, there is a corner;
3.17.3 tube longer than 15m, there are two bending;
3.17.4 tube longer than 8M, there are three corners.
3.17.5 is connected to a pipe of different diameter.
3.18 vertical installation of flexible metal conduit, in the following case, the crossing should set a fixed wire box.
3.18.1 tube conductor cross section for 50mm2 and below, each longer than 30m.
3.18.2 tube wire cross sections for 70mm2~95mm2, each longer than 20m.
3.18.3 tube wire cross sections for 120mm2~240mm2, each longer than 18m.
3.19 out pipe laying:
3.19.1 in accordance with design drawings, combined with structural characteristics, decoration, pay attention to ventilation, heating and plumbing, fire protection and other professional premise to determine accurate installation location pipe direction, boxes, line positioning.
3.19.2 prefabricated pipe brackets, hangers, according to the number of pipes, pipe diameter drill pipe clamp mounting holes. Boxes into the pipe hole, connector diameter well in advance, so a one hole, arranged neatly. Junction box useless knockouts are not allowed out, power distribution box (disc) not allowed to open the long holes and welding holes.
3.19.3 first boxes with good stability with expansion bolts. Then calculate and determine the bracket, hanger bracket, the specific position hanger installation. Should be fixed spacing uniform, corner of symmetry.
3.19.4 brackets, hangers and Terminal, turning point or junction boxes, distribution boxes, electrical appliances (dish) from the edge of 150~300mm. Pipe length does not exceed the 1000mm, shall be fixed at least two places. The middle bracket, hanger maximum distance should not exceed the limits set in table 3-13.
3.19.5 out timing, flexible metal wire and tube bending, bend radius should not be less than 3 times times the pipe diameter. Hold column, beam bending, use the dedicated adapter 30 ° bend attachments.
Flexible metal conduit laid out table 3-13 distance between fixing points
Laying conditions for distance between fixing points (mm)
Building or below horizontal laying <1000
People may touch parts <1000
Flexible metal conduit connect, connected with the junction box or fixed point junction <300

3.19.6 people flexible metal conduit and wires in the ceiling should be laid according to specified requirements.
3.19.7 ceiling panels inside the junction box if using flexible metal tubes and wires to lamps or devices, its length should not exceed 1000mm, matching should be applied at both ends of the connector locking, it tube skin protective earth conductor should be connected with the junction box pipe joined with PE guard wire in the box.
3.19.8 horizontal or vertical laying out fitted with flexible metal conduit that allows the deviation of 5 per thousand, full length deviation should not be greater than diameter of 1/2. Laid should be careful not to make flexible metal wire and broken pipe bending, it is hard to meet the quality standards.
3.19.9 settlement joints and expansion joints should be treated as compensation.
3.20 pipe Threading:
3.20.1 flexible metal wire and pipe Threading practices and technology standards and other wiring tube Threading practices are basically the same.
3.20.2 tube the total cross-sectional area of conductors, including insulation should not be greater than the pipe cross-sectional area within 40%.
3.20.3 equipment piping, thread prior to the line of control when tubing, pipe the total cross-sectional area of conductors, including insulation should not be greater than the pipe cross-sectional area within 60%.
3.20.4 flexible metal wire diameter of Guan Gong said numbered and plain tubes and wires, thick tieguangong that vary in diameter. For ease of construction and swap, and as shown in table 3-14.
3.20.5 insulated wire allows the number of pipe and the flexible metal conduit pipe
4 quality criteria
4.1 project:
4.1.1 material of flexible metal conduit, model, specification and location must comply with the design requirements and provisions of relevant national construction codes.
Inspection method: Visual check when laid, concealed, concealed works of checking records.
4.1.2 for laying pipes, boxes, box must be grounded and reliable, be integrated together. Selected specifications across the grounding line, and materials in compliance with the relevant national standard, pipe, grounding wire not welding connections.
Inspection method: Visual check and check the hidden inspection, inspection records.
4.1.3 wire and wire to the insulation resistance value must be greater than 0.5M.
Inspection method: practical testing and inspection insulation resistance test record.
4.2 Basic project:
4.2.1 concealed pipes: pipes and tubes and cartridges, boxes and other connections and mechanical connections should be solid, reliable electrical connections, the thickness is greater than 15mm.
4.2.2 laid pipes: Ming piping should be arranged regularly, firmly fixed, uniform distance between fixing points, corner said, fixed spacing in accordance with specifications.
4.2.3 when piping through the settlement joints and telescopic, with compensation measures, the wire enough.
Inspection method: observation of inspection, measuring with a ruler and check the hidden inspection records.
4.3 allowable deviation (3-16):
5 finished product protection
5.1 when concealed in a bar, should be protected better steel banding, not allowed to damage steel or any cutting steel.
5.2 mark Groove, tick do not push too hard, don't pick too broadly, excessive influence quality of civil engineering structures. Breaking structural reinforcement must be consent of the civil construction technical director before hamstring and civil measures.
5.3 when pouring concrete, must be electrical care to prevent phenomena such as pipeline connection from, found that the problem should be repaired in a timely manner.
5.4 laid pipe, should pay attention to the protection of civil decorations and clean, no pollution finishes such as walls.
5.5 after the tube should be promptly blocked well pipe. As construction progress and so Kwun Wat to wear line, blocking good boxes, cartons.
After 5.6 thread protection measures should be timely, in order to avoid paint pulp pollution boxes, boxes and wires. Install the lights, switch Sockets and other machinery, pay attention to civil decoration surface cleaning.
5.7 laid pipeline laying has been completed, such as casting and finishing works live civil repair should take timely measures on pipe, box, box protected to prevent contamination, resulting in clear difficulties in the future.
6 quality problems to be noticed
6.1 side installation switch, outlet boxes are not on the same level, beyond the allowable deviation should be telephoned line steady load, or take a short tube and stable box.
6.2 in-situ concrete and pipes in the ceiling fixed points within distance does not meet specifications, increase the fixed point.
6.3 next when piping, because location no and flexible characteristics of flexible metal conduit itself, resulting in uneven arrangement, horizontal and vertical degrees exceeding the allowed deviation. Perceptions of poor quality.
6.4 the pipeline across the grounding line with boxes, cartons, cards not in prison, clamp, wire of choice does not meet quality standards.
6.5 when threading pipe clogging occurs, mainly because it is not according to process requirements and so Kwun Wat to wear line, it tube is not blocked in a timely manner well, other types of tick cut cause the pipeline to be destroyed.
6.6 use of flexible metal conduit fittings of poor quality or specifications not matching, caused the pipeline joins poor mechanical strength and boxes, box joints loose and not in prison.
7 quality records
7.1 tubing manufactured materials, certificate of competency.
7.2 pipe accessories product certification.
7.3 the flame-resistant proof issued by the Fire Services Department (that year).
7.4 equipment, accessories, materials entering inspection records.
7.5 pre inspection projects and inspection record form.
7.6 cover engineering and inspection record form.
7.7 pipes and tubes threaded section for quality inspection and assessment records.

7.8 electrical insulation resistance test record.

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