Aluminum PG Clamps – Aluminum Parallel Groove Clamps for Overhead Conductors | Brass & Copper Parts India

Aluminum PG clamps (Parallel Groove clamps) are mechanical overhead power line connectors that join two conductors in a parallel-running orientation by compressing them together in a grooved body using bolts — without cutting or terminating either conductor. Brass & Copper Parts India manufactures aluminum PG clamps to IEC 61284, ANSI C119.4, IEEE 837, and utility-specific standards — supplying USA power utilities, EPC transmission and distribution line contractors, rural electric cooperatives, overhead line hardware distributors, and international electrification project contractors. Aluminum PG clamps are among the most widely used overhead line connectors globally, specified for conductor-to-conductor taps, jumper connections, mid-span splices, substation strain bus connections, and service drop taps on both aluminum (AAC, ACSR, AAAC) and copper conductors.

Product Overview

A parallel groove (PG) clamp consists of a machined or extruded aluminum alloy body with two or more parallel grooves (channels) machined to match the conductor diameter, a matching keeper (cover plate), and two or more U-bolts or hex bolts that draw the keeper toward the body, compressing both conductors in their respective grooves. The grooving profile creates intimate metal-to-metal contact along the full length of the conductor in the groove, achieving low contact resistance and high pull-out strength. PG clamps are available in same-conductor-size (equal) and two-conductor-size (reducing) configurations, covering a wide range of conductor diameters from 7 mm to 40 mm across standard utility conductor schedules.

Key Features

• No Crimping Tools Required: PG clamps are installed with a standard open-end spanner or socket wrench — making them the fastest-to-install mechanical connector technology for overhead line field work and ideal for remote rural and off-grid electrification projects.
• Both Conductors Remain Intact: Neither conductor is cut or terminated — the PG clamp joins them externally by parallel gripping, allowing both conductors to continue past the connection point. This enables T-tap connections without breaking the main conductor.
• IEC 61284 and ANSI C119.4 Compliant: Performance qualified per IEC 61284 (fittings for overhead lines) and ANSI C119.4 (connectors for overhead conductors), ensuring contact resistance, current carrying, vibration, and short-circuit performance meets utility approval requirements.
• Bi-Metallic (Al-Cu) Configurations Available: Standard aluminum body PG clamps join Al-to-Al; bi-metallic versions with stainless steel insert in one groove join aluminum conductor to copper conductor without galvanic corrosion at the Al-Cu interface — commonly used at substation bus and transformer terminal connections.
• Wide Conductor Range Coverage: Available across the full range of standard overhead conductor sizes from #6 AWG (7 mm dia) to 1272 kcmil Pheasant ACSR (37 mm dia) — covering distribution and transmission conductor schedules.
• Shear Bolt Versions: Shear-head bolts that shear off at a calibrated torque are available for fool-proof installation without a torque wrench — especially useful for field installations where torque wrench availability cannot be guaranteed.

Technical Specifications

Aluminum Alloy Grade Equivalents

Product Types and Variants

Standard 2-Bolt Aluminum PG Clamps (Equal and Reducing)

Standard 2-bolt parallel groove clamps are the most widely specified PG clamp configuration for distribution-voltage tap connections, jumper runs, and mid-span splice applications. The body contains two parallel grooves of equal (for same-conductor-size connections) or different (for reducing taps) diameters, and two bolts draw the keeper into full compression contact. Available in aluminum-to-aluminum (standard body) and aluminum-to-copper (bimetallic with insert) configurations. These cover conductor sizes from #6 AWG to 477 kcmil Hawk ACSR in distribution applications and are the most common PG clamp stocked by USA utility warehouses and electrical material distributors.

Heavy-Duty 3-Bolt and 4-Bolt PG Clamps for Transmission Conductors

For large-diameter transmission-voltage ACSR conductors (477 kcmil Cardinal to 1272 kcmil Pheasant, conductor OD 24–37 mm), heavy-duty 3-bolt and 4-bolt PG clamps provide the extended groove contact length and bolt clamping force required to achieve ANSI C119.4 Class A pull-out strength and current-cycling performance on high-current transmission lines. The body is extruded or forged from AA6082-T6 for maximum structural strength. These are used for jumper connections at tension towers, substation strain bus connections, and transformer HV terminal connections on 69 kV to 345 kV transmission systems.

Bimetallic Aluminum-Copper PG Clamps

Bimetallic PG clamps are used where an aluminum overhead conductor must be connected to a copper substation bus, copper transformer terminal, or copper service cable. One groove of the clamp is lined with a stainless steel or aluminum insert to prevent direct aluminum-copper contact; the copper conductor sits in the lined groove while the aluminum conductor occupies the standard groove. Without this bimetallic interface, direct Al-Cu contact in an outdoor environment causes galvanic corrosion that degrades contact resistance over time. IEC 61284 and ANSI C119.4 qualify bimetallic PG clamps specifically for outdoor Al-Cu connections.

Shear Bolt PG Clamps (Torque-Controlled Bolts)

Shear bolt PG clamps incorporate shear-head bolts that automatically shear at a calibrated torque value, providing a built-in torque control mechanism that eliminates the need for a torque wrench in the field. The bolt is tightened with a standard socket until the shear-off head snaps — confirming the correct installation torque has been applied. This is particularly valuable in rural electrification and distribution projects where the quality of individual lineman torque application is variable, and where ensuring consistent correct torque across thousands of connections on a large project is a quality-critical requirement.

Multi-Groove PG Clamps (3-Groove T-Tap and 4-Groove Cross-Tap)

Multi-groove PG clamps with 3 or 4 grooves allow a single clamp to simultaneously connect three or four conductors in parallel — used for multi-circuit bus connections at distribution substations, pole-mounted switching structures, and major tap poles where multiple circuits branch from a common main. The grooves may be equal-diameter (all same conductor) or mixed-diameter for tapping smaller branch circuits from a larger main. These reduce the number of separate connectors required at complex junction poles, decreasing installation time and pole-top congestion.

Applications by Industry

• Overhead Distribution (4–35 kV): Primary tap connections at pole-mounted distribution transformers, jumper connections on deadend poles, service drop taps, and conductor-to-conductor connections along medium-voltage distribution lines.
• Overhead Transmission (66–765 kV): Strain bus connections at transmission tower crossarms, jumper connections at tension structures, and ACSR to substation bus connections in 69 kV to 345 kV transmission substations.
• Substation Engineering: Rigid and flexible bus conductor connections within substations, transformer HV terminal connections, and switchgear bus taps requiring reliable, maintainable mechanical connections.
• Rural Electrification Projects: Distribution line construction in developing-country electrification programs where simple, no-tool-required PG clamps reduce installation labor cost and skill requirement.
• Telecom and Fiber Optic Aerial Plant: Structural messenger strand connections and ground wire taps on combined utility poles, including OPGW (Optical Ground Wire) termination connections at tower bases.

Manufacturing Process

PG clamp bodies are extruded from AA6061-T6 or AA6082-T6 billet to a near-net cross-section profile encompassing the groove geometry, then CNC-machined to final groove dimensions, bolt hole positions, and external profile. Groove diameter and surface finish (Ra ≤ 3.2 µm in grooves for good conductor contact) are controlled by CNC milling with calibrated cutters. Keeper plates are similarly extruded and machined. Bolt holes are tapped to precision thread class per bolt specification. All-aluminum bodies are anodized or chemical-film coated for corrosion protection. Bolts are hot-dip galvanized or supplied in stainless steel per the specification. Assembled clamps are function-tested (bolt engagement, groove geometry check) and sampled for electrical contact resistance testing per IEC 61284 at defined AQL. Batch documentation includes dimensional record, material certs, and test reports.

Quality Standards and Certifications

• ISO 9001:2015 Certified
• Performance qualification per IEC 61284 and ANSI C119.4 (Class A)
• Material conformance to ASTM B221 / EN 755 (extruded alloy bar) with 3.1 certs
• Contact resistance testing per IEC 61284 Table 2 criteria
• Third-party type testing by KEMA, Intertek, CESI, or equivalent accredited laboratory
• Individual utility specification compliance testing (PEPCO, Duke, Eversource, etc.) available

Why Choose Brass & Copper Parts India

• IEC and ANSI Dual Qualification: Both IEC 61284 and ANSI C119.4 type test reports available — enabling supply to USA utilities (ANSI) and international electrification projects (IEC) from a single source.
• Bimetallic Clamp Capability: Al-Cu bimetallic PG clamps available in standard and custom configurations — a specialized product not available from all overhead line hardware suppliers.
• Full Product Range: PG clamps, stirrup clamps, vise connectors, neutral bars, and terminal bars available as a complete overhead line hardware range — simplifying project procurement.
• Utility Approved Supply: Experience obtaining utility material approval (approved vendor list) at USA investor-owned utilities and rural electric cooperatives for PG clamp supply programs.
• Third-Party Test Reports: Accredited laboratory type test reports (KEMA/Intertek) to IEC 61284 and ANSI C119.4 available for utility engineering pre-qualification.

Frequently Asked Questions

What is a PG clamp and how is it different from a compression connector?

A PG (Parallel Groove) clamp mechanically grips two conductors side-by-side by bolt compression — requiring no special tools beyond a spanner. A compression connector is permanently crimped onto the conductor using a hydraulic tool. PG clamps are removable and quicker to install; compression connectors provide a more permanent, gas-tight joint but require compression equipment and trained operators.

What is the correct bolt torque for a PG clamp?

Torque values are stamped on each clamp body or provided in the installation datasheet, typically ranging from 14–55 N·m per bolt depending on bolt diameter and conductor size. Always use a calibrated torque wrench. Shear bolt versions eliminate torque wrench requirements — the bolt shears at factory-set torque.

Can PG clamps be used for aluminum-to-copper connections?

Standard aluminum PG clamps must NOT be used for direct aluminum-to-copper connections due to galvanic corrosion risk. Bimetallic PG clamps (with a stainless steel or tin-plated insert in the copper groove) must be used for Al-Cu connections in outdoor service per ANSI C119.4 and IEC 61284 requirements.

Are PG clamps suitable for ACSR conductors?

Yes. PG clamps are rated for AAC, ACSR, AAAC, and ACAR conductors. The groove diameter range must match the actual outer diameter of the specific ACSR conductor (which depends on the aluminum cross-section and steel core configuration). Always verify the clamp’s rated conductor diameter range against the actual conductor OD before installation.

What is a shear bolt PG clamp and when should it be used?

A shear bolt PG clamp uses bolts with a separate shear-off head that breaks at a calibrated torque value, providing built-in torque control without a torque wrench. Use shear bolt clamps when large numbers of connections are being made in the field (reducing QC variability), when torque wrenches are not consistently available, or when the utility specification explicitly requires shear bolt connectors.

What is the minimum order quantity for PG clamps?

Evaluation/approval samples: 25–50 pieces per size. Standard orders: MOQ 100 pieces per SKU. Bulk project supply: 500+ pieces per SKU at container-load pricing. Framework contracts for annual utility procurement programs available.

Do you supply PG clamps with hot-dip galvanized or stainless steel bolts?

Yes. Standard PG clamps are supplied with hot-dip galvanized alloy steel bolts. Stainless steel SS316 bolts are available for coastal, marine, and high-humidity applications where galvanized bolts would corrode prematurely. Please specify bolt material preference when ordering.

Suggested Internal Links

• All Aluminum Parts
• Aluminum Vise Connectors and Vise Clamps (related product)
• Aluminum Alloy Stirrup Clamp Hotline Bail Clamp (related product)
• Aluminum Terminal Bars and Neutral Bars (related product)
• Electrical Accessories

Request a Quote for Aluminum PG Clamps

Brass & Copper Parts India supplies IEC 61284 and ANSI C119.4 qualified aluminum PG clamps (parallel groove clamps) to USA power utilities, EPC contractors, and overhead line hardware distributors. Provide your conductor sizes (AWG/kcmil), connection type (equal or reducing, Al-Al or Al-Cu), number of bolts, quantity, and any utility approval requirements for a technical and commercial quotation. Get a quote today.