technical of BUS BAR CLAMPS
1. Ultimate Tensile Strength (UTS)
1. For Aluminum (AL 6063-T6): ≥190–220 MPa
2. For Copper (ETP Grade): ≥200–250 MPa
3. The UTS depends on the clamp body and bolt materials, ensuring resistance to mechanical pull-out or conductor break-off under stress.
2. Working Load / Safe Working Load (SWL)
1. SWL is typically 30–40% of UTS to maintain long-term safety.
2. Typical SWL Range: 2–6 kN, depending on size and application
3. Must sustain:
I. Busbar vibration
II. Cable pulling tension
III. Thermal expansion pressure
3. Conductor Diameter Compatibility
1. Designed for:
I. Round conductors (6 mm² to 300 mm²)
II. Flat conductors/busbars (width 25–100 mm, thickness 3–10 mm)
2. Conductor groove is precision-machined or milled to accommodate specific profiles
3. Slotted or U-type clamp options are available
4. Slip Strength:
1. Critical for reliable connection—must not allow conductor slippage due to vibration, thermal cycling, or tension
2. Minimum slip strength: ≥90% of the conductor's rated tensile strength
3. Achieved by:
I. Grooved inner clamp surface
II. Proper bolt torque application (usually 25–60 Nm)
III. Use of serrated washers
5. Temperature Withstanding Capacity:
1. Continuous operation: –20°C to +90°C
2. Short-term withstand: up to 250°C (during fault or overload conditions)
3. Clamps must maintain:
I. Mechanical strength
II. Electrical contact integrity
III. Resistance to thermal expansion mismatch
6. Corrosion Resistance:
1. Tin-plating or anodized coating provides:
I. Resistance to oxidation, moisture, and electrolytic corrosion
II. Suitability for outdoor substations or polluted industrial zones
2. Salt Spray Resistance: ≥500 hours (ASTM B117 compliant)
3 Stainless steel bolts resist rust and pitting
7. Impact & Fatigue Strength:
1.Designed to handle:
I. Electrical switching shock
II. Vibration from connected equipment or cables
III. Frequent maintenance or re-tightening cycles
2. Tested for 10,000+ mechanical and electrical cycles without slippage or deformation
8. Mechanical Endurance:
1. Service life: ≥30 years
2. Endures:
I. Continuous torque loads
II. Current cycling
III. Moisture & chemical exposure
3. Must retain clamping force and electrical contact under aging
9. Design Safety Factors:
1. Mechanical Safety Factor: ≥2.5–3.0
2. Electrical Safety Factor:
I. Contact resistance < 100 μΩ
II. Cross-section suitable for 100% rated current of conductor
3. Designed to prevent:
I. Hot spots
II. Arcing
III. Uneven torque distribution
Top 5 Quality Assurance
1. Type & Routine Testing as per IEC 61284 / IS 5561
I. Mechanical grip test (minimum slip force verification)
II. Temperature cycling test
III. Short-circuit current test (for high-current passage and expansion simulation)
IV. Contact resistance measurement (<100>
2. Material Testing & Certification
a. Aluminum body tested for:
I. Composition (Al-Si-Mg alloys as per ASTM B108)
II. Tensile strength and elongation
b. Bolts & nuts tested for:
I. Galvanizing thickness
II. Hardness (Brinell or Rockwell)
III. Thread conformity (gauge test)
3. Dimensional Inspection
a. 100% check of:
I. Groove width and depth
II. Bolt hole alignment and spacing
III. Surface finish and casting integrity (no cracks or voids)
b. Templates/gauges used for consistent tolerance control
4. Corrosion & Environmental Resistance Testing
a. Salt spray test (ASTM B117): ≥ 500–1000 hours for marine/industrial zones
b. Moisture ingress test for clamps with sealing (if any)
c. Bimetallic compatibility testing (if Cu-Al contacts are used)
5. Traceability & Documentation
a. Each clamp marked with:
I. Manufacturer name/logo
II. Size/type code
III. Batch number
b. Supplied with:
I. GTP (Guaranteed Technical Particulars)
II. Routine test reports
III. ISO 9001 compliance certificate
IV. Optional third-party inspection reports (CPRI/ERDA)