JBTL Series Copper-Aluminium Parallel Groove Clamp
The JBTL Series copper-aluminium parallel groove clamp is a bolted bimetallic connector designed for non-tension electrical connections between copper and aluminium conductors. It is commonly used for parallel connections, branch connections, jumper loops and equipment leads in overhead power distribution systems.
The clamp incorporates dedicated copper and aluminium conductor-contact areas to provide a controlled transition between dissimilar conductor materials. Its shaped parallel grooves help distribute clamping pressure along the conductors, while the bolts, nuts and washers maintain the required contact force.
This product is intended to transmit electrical current and provide adequate mechanical retention at a non-tension connection point. It must not be used as a dead-end or full-tension conductor fitting.
Key Features
- Designed for copper-to-aluminium conductor connections
- Suitable for non-tension parallel joints and branch connections
- Asymmetrical groove design for different conductor materials or sizes
- Two-bolt and three-bolt configurations available
- Bolted construction allows installation with standard tools
- Available for conductor cross-sections from approximately 16 mm² to 240 mm²
- Optional insulating cover available for additional environmental and accidental-contact protection
- Model, conductor range and bolt configuration can be customized according to approved drawings
Typical Materials and Surface Treatment
| Component | Typical Material | Typical Surface Treatment |
|---|---|---|
| Aluminium conductor section | High-conductivity aluminium or corrosion-resistant aluminium alloy | Natural finish with joint compound where specified |
| Copper conductor section | High-conductivity copper or copper alloy | Bare copper or project-specified finish |
| Copper-aluminium transition | Metallurgically bonded, brazed or manufacturer-approved transition structure | According to the approved production process |
| Bolts, nuts and washers | Carbon steel | Hot-dip galvanized or project-specified coating |
| Optional insulating cover | Weather-resistant insulating polymer | Black, red or customized colour |
The exact material grades, copper-aluminium bonding method, bolt grade and coating thickness must be confirmed using the manufacturer’s drawing and bill of materials.
Common JBTL Model Selection
| Model | Typical Conductor Cross-Section | Typical Bolt Configuration |
|---|---|---|
| JBTL-0 | 16–25 mm² | 2 × M10 × 45 |
| JBTL-1 | 35–50 mm² | 2 × M12 × 45 |
| JBTL-2 | 70–95 mm² | 3 × M12 × 45 |
| JBTL-3 | 120–150 mm² | 3 × M16 × 65 |
| JBTL-4 | 185–240 mm² | 3 × M16 × 70 |
Model notice: JBTL model designations and conductor ranges are not completely uniform among manufacturers. Some catalogues use model numbers such as JBTL-0 to JBTL-4, while others use range-based designations such as JBTL-10/70, JBTL-35/120 or JBTL-50/240. The final selection must be based on the actual copper and aluminium conductor diameters, not only the nominal cross-sectional area.
Electrical and Mechanical Data
| Item | Specification |
|---|---|
| Product type | Bimetallic parallel groove clamp |
| Connection type | Bolted, non-tension electrical connection |
| Conductor combination | Copper conductor to aluminium conductor |
| Typical conductor range | 16–240 mm², depending on model |
| Number of bolts | Two or three, depending on model |
| Installation environment | Outdoor or indoor distribution systems |
| Rated voltage | Determined by the complete line system and project specification |
| Tensile function | Non-tension connection only |
| Customization | Conductor range, bolts, materials, dimensions, cover and packaging |
Applications
- Copper-to-aluminium conductor transition connections
- Overhead distribution-line branch connections
- Parallel conductor connections
- Transformer and switchgear lead connections
- Jumper-loop and bypass connections
- Distribution-network construction and maintenance
- Rural electrification and grid-upgrade projects
Installation Recommendations
- Confirm the material, diameter and cross-section of both conductors.
- Select a clamp whose approved groove range covers the actual conductor diameters.
- Disconnect and verify that the circuit is de-energized before installation unless an approved live-line procedure and product are specified.
- Clean conductor contact surfaces and remove loose oxide, dirt and grease.
- Apply an approved oxide-inhibiting joint compound to the aluminium contact area when required.
- Place the copper conductor in the copper groove and the aluminium conductor in the aluminium groove.
- Tighten the bolts evenly in stages using the torque specified on the approved drawing.
- Do not exceed the recommended tightening torque, as excessive torque may deform or damage the conductor.
- Install the optional insulating cover where required by the project.
- Inspect the connection after installation and during scheduled line maintenance.
Quality Inspection
Recommended inspection and testing items include:
- Material verification for copper and aluminium components
- Dimensional inspection against the approved drawing
- Conductor groove and fit inspection
- Visual examination of the copper-aluminium transition area
- Bolt, nut and washer inspection
- Coating-thickness inspection for galvanized steel fasteners
- DC resistance measurement when specified
- Temperature-rise or heat-cycle testing when required
- Mechanical slip or holding-strength testing according to the purchase specification
- Assembly, marking and packaging inspection
Standards and Project Requirements
The JBTL parallel groove clamp may be manufactured and tested according to the approved customer drawing, utility specification and applicable requirements of the following standards:
- GB/T 2314 – General technical requirements for electric power fittings
- DL/T 765.1-2021 – Overhead distribution line fittings, Part 1: General technical requirements
- DL/T 765.2-2021 – Overhead distribution line fittings, Part 2: Fittings for bare conductors up to 35 kV
- GB/T 2317.3-2008 – Heat-cycle test methods for electric power fittings
- IEC 61284 – Requirements and tests for overhead-line fittings, when specifically required and verified
Compliance with any listed standard must be verified for the ordered model through the applicable drawing, inspection report or type-test documentation. Standards should not be printed on the product page as certified compliance unless supporting records are available.
Information Required for Quotation
- Copper conductor type and cross-section
- Aluminium conductor type and cross-section
- Actual outside diameter of both conductors
- Required JBTL model or approved drawing
- Two-bolt or three-bolt configuration
- Required electrical-current or heat-cycle test
- Required mechanical holding strength
- Required fastener material and surface treatment
- Whether an insulating cover is required
- Applicable standard, quantity, marking and packaging
Frequently Asked Questions
Can the JBTL clamp connect copper directly to aluminium?
Yes. The JBTL series is specifically designed for copper-to-aluminium conductor connections. The copper conductor must be installed in the designated copper groove and the aluminium conductor in the designated aluminium groove.
Is this a tension clamp?
No. It is intended for non-tension electrical connections and branch joints. It must not replace a dead-end or tension clamp.
How should the correct model be selected?
Selection should be based on the material, cross-section and actual outside diameter of both conductors. The manufacturer’s groove dimensions and approved drawing must be checked before ordering.
Can different conductor sizes be connected?
Yes, when both conductor diameters fall within the approved groove ranges of the selected model. Exact compatibility must be confirmed before installation.
Is an insulating cover available?
Yes. A compatible insulating cover can be supplied where protection against accidental contact, contamination or environmental exposure is required.
