Busbars Installation and Acceptance Standards

Busbars Installation and Acceptance Standards

1. Installation of Support (Suspension) Brackets and Protective Nets

1.0.1 This chapter applies to the installation of busbar support (suspension) brackets, distribution devices, and protective net barriers between electrical equipment.

1.0.2 Inspection of Support (Suspension) Bracket Installation

OperationInspection ItemsPropertiesQuality StandardsInspection Methods and Instruments
Profiled SteelInspection Structural Steel Specifications In accordance with design specificationsComparative Blueprint Design Review
Permissible Deviation for Full Length Straightness of Structural Steel ≤5mmDimensional Examination with a Ruler
Appearance of Bolts and Machined Surfaces Smooth, without deformationVisual Inspection
Bracket Installation  Elevation Error ≤5mmLevel Instrument Check
Horizontal Error Measurement Verification Using a Ruler
Vertical Error Along Direction 
Diagonal Error of Brackets 
Fixation of Supports (Hangers)MainlySturdy and reliableLever Operation Inspection
MiscellaneousPaintRust removalClean, rust-freeVisual ExaminationVisual Examination
Application of anti-corrosive paintUniform, no missed spotsUniform, no missed spots
GroundingMainlySolid, with good conductivityEngage and conduct inspection.

1.0.3. Inspection of  Protective Mesh Installation

ProcessInspection ItemsPropertiesQuality StandardsInspection Methods and Tools
Structural Steel
Profile Steel Specifications As per design specificationsComparative review against blueprint designs
Permissible Tolerance for Full Length Straightness of Profile Steel ≤5mmMeasurement inspection
Appearance of Bolts and Machined Surfaces Smooth, no deformationVisual observation inspection
Fabrication of FrameworkFrame WeldingMainlySturdy, the appearance and process comply with welding specification requirements.Pull and observe for inspection.
Dimensional Deviation ≤5mmCheck with a ruler
Diagonal Error ≤5mm
Frame Unevenness ≤5mm
Installation of Mesh FenceMesh Panel Flatness Inspection No protrusions or depressions.Inspect with a ruler.
Mesh Opening Inspection Sturdy, uniform, and consistent.Perform a lever check.
Gap between Frame and Mesh Panel ≤5mmInspect with a ruler
Vertical Error of Mesh FenceMainly≤5mm
MiscellaneousPaint MainlyMainlyClean, free from rust.Observation and Inspection
Application of Anti-Corrosion Paint Uniform, no uncoated areas.
GroundingGrounding of Wire MeshMainlyReliably grounded with flexible wiring.Engage and conduct inspection
Earthing of FrameworkSturdy, with excellent conductivity.

2. Insulator Installation

2.1 This section applies to the installation of suspension insulator strings, post insulators, and wall-through bushings, among others.

2.2 Inspection of suspension insulator string installation.

ProcessInspection ItemsPropertiesQuality StandardsInspection Methods and Tools
Visual Inspection  Verification of Specifications and Models As per design specifications,Observation and inspection.
Ceramic Parts AppearanceMainlySmooth, intact, and crack-free,
Inspection of Ceramic-Metal Adhesive JointsMainlyFirmly bonded,
Connection Hardware and Accessories Complete and undamaged,
Spring Pin Inspection Adequately elastic,Lever Operation Inspection
Uniform Pressure Ring and Shield Check Whole, without deformation,Visual Inspection
Installation of Insulator StringTests Before Insulator AssemblyMainlyQualified,Inspection Test Report
Direction of Connection Bolts, Rivets, Spring Pins, etc. Consistent,Visual Inspection
Coordination between Ball Head Rings, Bowl Head Plates and Locking Pins Flexible, without obstruction,Lever Operation Inspection
Check of Connection Hardware Anti-loosening MeasuresMainlyLocknuts tightened against loosening, cotter pins opened,Visual Inspection
Allowable Tilt Angle of Suspension Insulator String (when not designed) ≤5°,Visual Inspection
Tension Received by Each String When Insulator Strings are in ParallelMainlyUniform,
Overall Check Before Lifting Insulator Strings Clean, correctly assembled, cup facing upwards.

2.0.3 Installation Inspection of Pillar Insulators

ProcessInspection ItemsPropertiesQuality Standards:Inspection Methods and Tools
Visual Inspection Exterior of Ceramic ComponentsMainlySmooth, intact, and free of cracks.Visual Examination
Verification of Ceramic-Iron AdhesionAdhered securely, without gaps.
Insulator Installation  Error in Insulator Base Level ≤5mmCheck with a ruler.
Error in Centerline of Insulator Pillars within Busbar Branch SegmentMainly≤2mmCheck with a ruler.
Vertical Error in Stacked Insulator Pillars 
Thickness of Gasket Between Pure Ceramic Insulator and Metal Contact SurfaceMainly≥1.5mm
Fixation of InsulatorsMainlyAll bolts are in place and tightly secured.Check with a wrench.
Grounding Arrangement of Ground Wires There is consistent directionality.Conduct a visual inspection.
Connection to Grounding GridMainlyThe structure is sturdy, with excellent conductivity.Toggle and check for continuity.

2.0.4 Installation and Inspection of Wall Penetration Sleeves

ProcessInspection Items:PropertyQuality Standards:Inspection Methods and Tools
Visual Inspection Ceramic Part AppearanceMainlySmooth, unbroken, and free from cracks.Observation and inspection.
Ceramic-Iron Adhesion CheckMainlySecurely bonded with no gaps.
Installation of CasingCompatibility of Reserved Hole Diameter and Bushing Insertion Part >5mmCheck with a ruler
Maximum Thickness of Concrete Installation Plate ≤50mm
Steel Plate for Fixing Bushings of 1500A and Above Does not form a closed magnetic circuit.Observation and inspection.
Flange PositionVertical installation The flange should be oriented upwards.
Horizontal installation The flange should be on the outside.
600A and above casing.End Metal ClampClamp materialMainlyNon-magnetic materials.Observation and inspection.
Thickness ≥3mm 
Connected at the same potential as the busbarMainlySturdy and reliableObservation and inspection.
Oil Filling CasingSeal InspectionMainlyLeak-freeLeak-freeNormal
Oil Level IndicatorMainlyNormal
Connecting BoltsMainlyComplete and securely fastenedInspect with a wrench.
Grounding Terminal and Unused Voltage Extraction TerminalMainlyReliable groundingTurn and establish grounding.

3. Installation of Rectangular Busbars

3.0.1 This chapter applies to the installation of AC and DC rectangular busbars as well as slotted busbars.

3.0.2 Inspection of Rectangular Busbar Installation

ProcessInspection Items:PropertyQuality StandardsInspection Methods and Instruments
Busbar Processing Configuration Visual InspectionSurface Inspection Smooth, free from cracks and creasesObservation and inspection.
External Inspection Flat, devoid of deformations and twists
Threaded Surface MachiningOverlap LengthMainlyCompliant with GBJ 149-1990 regulationsCheck against the standard. Inspect with a ruler.
Screw Hole Layout and SpecificationsMainly
Center Distance Error Between Screw Holes ±0.5mmInspect with a ruler.
End Face Appearance Flat, smooth, free of sharp corners and burrs.Observation and inspection.
Contact Surface Flatness  Even and void of local depressions.Measure with a steel ruler.
Contact Surface Cross-Section ReductionMainlyCopper ≤3%, Aluminum ≤5%.Inspect with a vernier caliper.
Busbar bendingAllowed Minimum Bending RadiusMainlyIn accordance with GBJ 149-1990 regulations.Check against standards using a template.
Minimum Distance from Bending Start Point to Joint Edge ≥50mmInspect with a ruler.
Distance from Bending Start Point to Busbar Supporter Edge ≥50mm; ≤0.25 pivot distance.
Twisting Length of 90° Bend in mm 2.5 to 5 times the width of the busbar
Appearance of Bending PartMainlyNo cracks, no noticeable creases.Observation and inspection.
Bending Radius on the Same Section of Three Phases Consistent.Inspect using a template.
Bending Radius of Multiple Busbars in the Same Phase Consistent.Observation and inspection.
Bending Radius of Branch Busbars with Same Layout 
Busbar InstallationHardware Installation   Hardware Inspection Clean, undamaged.Observation and inspection.
Single-Phase AC Busbar Hardware ConnectionMainlySecure, with no closed magnetic circuit.
Appearance of Fixing Device No sharp angles or burrs.
Busbar InstallationGap Between Busbar and Upper Clamp When Busbar is Horizontal 1mm~1.5mmInspect with a ruler.
Distance Between Upper Clamp and Busbar When Busbar is Vertical 1.5mm~2mm
Stress Check Between Busbar and SupportMainlyNo external stress.Observation and inspection.
Interlayer Gap of Multiple Layers of Busbar in the Same Phase Uniform thickness along the generatrix.Inspect with a ruler.
Busbar Fixation Dead Point on Insulator Set one for each segment, either along the entire length or at the midpoints of the two expansion sections.观察检查
Busbar connectionDistance Between Supporter and Joint Edge ≥50mmInspect with a ruler.
Connections Between Busbars and Between Busbar and Equipment TerminalsMainlyNo external stressCheck during connection.
Overlap SurfaceMainlySmooth, without an oxidation layer, the silver plating must not be ground, coated with electrical load grease.Observation and inspection.
Terminal Connection and Screw Shape AppearanceMainlyNo spring pads 
Flat Washer 
Tin-coated copper
Observation and inspection.
Lock Nut Complete and tight-fitting
Connecting BoltMatched with Hole Diameter ≤1mmInspect with bolts
Bolt Insertion Direction When the busbar is laid flat, it goes from bottom to top, and all other nuts are on the maintenance side.Observation and inspection.
Anti-loose Component Appearance Complete, intact, and flattened.
Tightening Torque According to the stipulations of GBJ 149-1990.Inspect with a torque wrench according to the standard.
Exposed Length After Bolt Tightening 2~3 buttonsObservation and inspection.
Gap Between Adjacent WashersMainly≥3mmObserve or inspect with a ruler
Installation of Expansion Joint No streaking, breakage, or creasing phenomena.Observation and inspection.
Overall inspectionThe distance between charged bodies and between charged bodies and other objects.MainlyIn accordance with GBJ 149-1990 regulations.Inspect according to the standard using a ruler.
Color matching and painting. Complete and correctObservation and inspection.

4. Installation of Enclosed Bus Ducts in Shared Boxes

4.0.1 This chapter applies to the installation of enclosed bus ducts (rectangular, slot-type, heavy-duty, cable bus) in shared boxes.

4.0.2 Inspection of enclosed bus duct installation in shared boxes.

ProcessInspection ItemPropertyQuality StandardsInspection Methods and Tools
Shared Busbar Inspection  Exterior Appearance of the Case Complete, free of cracks and deformations.Observation and inspection.
Conductor  Appearance Observation and inspection.Observation and inspection.
Threaded Interface InspectionMainlyObservation and inspection.
Cable BusbarMainlyObservation and inspection.
Insulator InspectionAppearance Inspection Observation and inspection.Observation and inspection.
Base ConnectionMainlyBolt FasteningLever Inspection
Insulation Test Good InsulationMeasure with a megaohmmeter.
Shared Busbar InstallationInterphase distance error. ≤5mm≤5mm
Conductor Expansion JointTelescopic Joint AppearanceMainlyNo Local FracturesObservation and inspection.
Threaded Interface Protective Layer Coating Adequate and Uniform
Threaded Fastening TorqueMainlyAs per GBJ 149-1990 standardsInspect according to the standard.
Rectangular Busbar InstallationMainlyInstall according to the rectangular busbar guidelines.As per Rectangular Busbar Installation Guidelines
Cable Busbar InstallationMainlyFollow the cable routing regulations.As per Cable Line Guidelines
Change of position required for busbar lengths exceeding 300m~400mMainlyNo less than one cycle or as stipulated by the design.Not less than one cycle or as per design specifications
Soft Connection between Heavy-Duty Busbar and Equipment The cross-sectional area of the connection line should be no less than that of the busbar.Connection line cross-section not less than busbar cross-section
Shell Interface Assembly It must be sturdy and well-sealed.Sturdy and Well-Sealed
Shell Expansion JointTelescopic joint seal.MainlyGoodObservation and inspection.
The two ends of the telescopic joint are conductively connected. Good and SturdyObservation and Lever Operation Inspection
Chassis GroundingMainlyReliable, full-length conductivity is good.Reliable, Full-Length Conductivity Excellent

5. Installation of Six-Tube Busbar

5.0.1 This chapter applies to the installation of indoor and outdoor high voltage distribution device six-tube busbars.

5.0.2 Inspection of six-tube busbar installation.

Process StepsInspection ItemsPropertyQuality StandardsInspection Methods and Instruments
Aluminum Alloy Tubing and Fittings Aluminum Alloy Tube Surface Inspection Smooth, free of cracksObservation and inspection.
Aluminum Alloy Tube End Flat and perpendicular to the axisCheck with a ruler.
Aluminum Alloy Tube Bend Radius Compliant with GBJ 149-1990 regulationsInspect according to the standard.
Metal Fittings Inspection Smooth, undamaged, and crack-freeObservation and inspection.
Tube Busbar Welding Welding MethodMainlyArgon arc weldingObservation and inspection.
Weld Seam DimensionsMainlyIn accordance with GBJ 149-1990 regulations,Inspect according to the standard.
Bevel Processing Surface treatment within a 50mm range on both sidesClean, free of oxidation film,Clean, free of oxidation film,Observation and inspection.
Bevel machining surfaceNo burrs, no flash.No burrs, no flash.
Alignment Bending offset ≤0.2%Check with a ruler.
Centerline deviation ≤0.5mm
Liner Pipe Longitudinal axis positionMainlyLocated at the center of the weld.Check with a ruler.
Gap between the pipe and the generatrix ≤0.5mm
Weld Seam InspectionWeld seam height 2mm~4mmCheck with a ruler.
Weld seam appearanceMainlyComplies with DL/T 754-2001 specificationsObservation and inspection.
Tube Busbar Installation Hardware ConnectionMainlyNo closed magnetic circuitNo closed magnetic circuit.
Hardware Fastening Flat and sturdyFlat and sturdy.
Distance from Weld to Support Edge ≥50mmCheck with a ruler.
Clearance Between Busbar and Sliding Supporter Shaft Seat 1mm~2mm
Expansion Joint AppearanceMainlyNo cracks, breaks, or creases.Observation and inspection.
Busbar Terminal Shield Device Surface is smooth, without burrs or unevenness.Observation and inspection.
Three-Item Busbar Tube Axis Parallel to each other.Observation and inspection.
Equalizing Ring and Shield InspectionMainlyComplete, without distortion, and securely fastened.
Overall InspectionDistance Between Live Parts and Other Objects As stipulated by GBJ 149-1990.Inspect according to the standard.
Busbar Phase Color Indicator Complete and correct. 

6. Soft Busbar Installation

6.0.1 This section applies to the installation of distribution device soft busbars and generator set combined wires.

6.0.2 Inspection of Soft Busbar Installation

ProcessInspection ItemsPropertyQuality StandardInspection Methods and Instruments
Wire and Hardware Inspection    Wire AppearanceMainlyNo breakage, looseness, or damage, and expanded wires should be free from dents and deformations.Observation and Inspection
Wire Cut-off Section Neat, no looseness or burrs, and perpendicular to the wire axis.
Connector Model and SpecificationsMainlyMatches with the connecting wires.
Connector and Fastener AppearanceMainlySmooth, without cracks, burrs, or unevenness.
Wire and Terminal Clamp Contact Surface TreatmentMainlyClean, without oxide film, and coated with electrical composite grease.
Hydraulic CrimpingExpanded Wire and Strain Clamp Crimp ConnectionMainlyThe central gap is filled with the corresponding material.Observation and Inspection
Wire Insertion Length into ClampMainlyEqual to the length of the line clip.
Crimping Die and Crimping Pliers Inspection Specifications match.
Overlap Length of Adjacent Crimp Sections ≥5mmCheck with a ruler
Inspect after crimpingSwage tube bending degree ≤2%Check with a ruler
Surface of the swaged tube Smooth, without cracks or indentations.Observation and Inspection
Wire appearance at the tube endMainlyNo bulges or looseness.
Hexagonal across-flats dimension in millimetersMainlyOuter diameter of the continuation tube is less or equal to 0.866D+0.2.Check with a ruler
Compression Test Specimen ExperimentMainlyApprovedInspect the Test Piece Experiment Report
Bolt ConnectionThe aluminum strip is wound between the conductor and the wire clamp Consistent with the outer aluminum strand’s direction of rotation.Observation and Inspection
The exposed length of the aluminum tape clamp ≤10mmCheck with a ruler
Aluminum tape port processing Press back into the clamp.Observation and Inspection
Connecting BoltMainlyEnsure uniform tightening, with the bolt revealing two to three threads beyond the nut.Check with a torque wrench
Nail Zhang wire clamp leads to the busbar arrangement of the equipment. Complete, without interruptions.Observation and Inspection
Flexible Busbar Installation and Overall InspectionThe busbar arrangement within the gear pitch. SeamlessObservation and InspectionObservation and Inspection
The configuration of connecting hardware parts. Complete, secure.
Busbar sag error.Mainly-2.5% ~ +5% (under design temperature)Observation and Inspection
The sag of the three busbars within the same pitch. ConsistentObservation and Inspection
The bend and sag of branch lines with the same layout. 
The inter-line and frame structure distance of jumper and lead down lines.MainlyAs stipulated by GBJ 149-1990.Inspect in accordance with standards
Composite ConductorFixed Wire Clamp Spacing ErrorMainly≤±3%Check with a ruler
Intersection Angle Between Fixed Wire Clamp and Conductor 90°Check with a square ruler
Runout ConsistentObservation and Inspection
Busbar is connected to the electrical terminal. The terminal is undamaged and free of deformations.Observation and Inspection
Adjustable fixture inspection. The adjustment nut is securely tightened.Inspect with a wrench
Busbar phase color identification. Complete and correct.Observation and Inspection
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Founder of MachineMFG

As the founder of MachineMFG, I have dedicated over a decade of my career to the metalworking industry. My extensive experience has allowed me to become an expert in the fields of sheet metal fabrication, machining, mechanical engineering, and machine tools for metals. I am constantly thinking, reading, and writing about these subjects, constantly striving to stay at the forefront of my field. Let my knowledge and expertise be an asset to your business.

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