PG Clamp Selection for Overhead Conductors: Aluminum, Copper, Bimetal, and Bolt Configuration

A PG clamp can fit both conductors and still be wrong for the connection. A material mismatch may create an unstable aluminum-copper interface, while an incorrect groove or tightening requirement can damage strands, raise contact resistance, or make the installation impossible to inspect consistently. A useful RFQ must therefore define both conductors, the connection duty, the bolt arrangement, and the evidence required for acceptance.

Start with the Two Conductors, Not the Clamp Model

Record the run conductor and tap conductor separately. For each side, state the metal, conductor construction, nominal cross-section, actual outside diameter, stranding, and whether the conductor is bare, covered, or insulated. AAC, AAAC, ACSR, solid copper, and stranded copper of the same nominal cross-section may not share the same diameter or surface behavior.

A conventional bolted PG clamp is normally evaluated as a bare-conductor connector. If the project uses covered or insulated cable, specify whether insulation will be removed and how the exposed connection will be sealed. Do not assume that a standard PG clamp pierces insulation. If the connection must be made without stripping, assess a purpose-designed insulation piercing connector instead.

These are selection directions, not substitutes for the manufacturer’s model data. A supplier may approve additional conductor combinations only when the drawing, test evidence, and installation instruction cover the exact pair.

Single-bolt aluminum parallel groove clamp. The conductor pair and published groove limits still govern its use.

Aluminum, Copper, or Bimetal: What Changes?

Aluminum PG Clamps

Use an aluminum-body clamp where both conductor sides are aluminum-based and the selected model explicitly accepts their constructions and diameters. The RFQ should identify the body material, bolt and washer material or coating, contact compound, and required corrosion test. Writing only “aluminum PG clamp” leaves the alloy, hardware, and surface protection open to interpretation.

Copper PG Clamps

For copper-to-copper joints, specify whether the conductors are solid or stranded and whether bare, tinned, or another finish is required. The clamp’s current-carrying and thermal performance must suit the connection duty. A grounding connection may also be subject to a specified fault-current withstand and earthing standard; normal load current alone is not an adequate acceptance criterion.

Bimetal PG Clamps

For an aluminum-to-copper transition, request a connector specifically identified for that combination. The drawing should label the Al and Cu grooves and show the transition interface. Ask for the sealing or compound arrangement, storage requirements, and installation orientation where applicable. A generic aluminum clamp should not be accepted for an Al-Cu joint unless its manufacturer provides model-specific approval and evidence.

A bimetal PG clamp must place each conductor in its designated groove and within its own published range.

Do the Two Conductor Ranges Need to Overlap?

Not necessarily. What matters is that each conductor fits the range assigned to its groove. A symmetric clamp may publish one common range for both grooves. An asymmetric tap connector may publish a wider run range and a smaller tap range. In that case, the run and tap values do not need to overlap; they need to fall within their respective limits.

Check both nominal cross-section and outside diameter. Cross-section is convenient for schedules, but groove contact is controlled by geometry. Request a drawing or data sheet that identifies groove A and groove B, the accepted conductor types, the cross-section limits, and diameter limits. If a catalogue only states “16–300 mm²,” it does not prove that every main-and-tap combination inside that span is valid.

Choose the Bolt Configuration from Verified Performance

One-, two-, and three-bolt clamps provide different contact lengths and pressure distributions, but bolt count alone does not establish ampacity, slip strength, or fault-current performance. A larger conductor does not automatically require a particular number of bolts unless the utility specification or tested manufacturer table says so.

Torque must come from the offered clamp’s instruction or controlled technical sheet. Do not derive it from M8, M10, or M12 bolt size, and do not copy a value from another brand or model. During installation, use the specified socket and a calibrated torque wrench. Tighten multiple bolts in the stated sequence, commonly in alternating increments where the instruction requires it, then record the final result. Re-torque after service only when the manufacturer or utility procedure calls for it.

A two-bolt layout changes contact length and installation sequence; its performance remains model-specific.

Match the Clamp to the Connection Duty

• Jumper or parallel connection: define both conductor routes, available clearances, expected movement, and whether the clamp carries current only or also sees mechanical load.

• Tap or equipment downlead: identify the run and tap sides, load current, conductor support, bending clearance, and water-shedding orientation.

• Grounding connection: state the grounding conductor material and fault-current requirement, not just its cross-section.

• Energized installation: a standard PG clamp is not automatically a live-line device. Select an approved hot line clamp and follow the utility’s live-working method where shutdown is not possible.

The connection also belongs to a wider overhead system. Review conductor support, insulation clearances, adjacent fittings, and work access as part of the aerial cable accessory arrangement, rather than treating the connector as an isolated bill-of-material item.

How to Write Corrosion and Documentation Requirements

Avoid phrases such as “weatherproof” or “corrosion-proof.” State the service environment and request the relevant evidence. The supplier package should identify body and hardware materials, coatings and coating thickness where specified, contact compound, bimetal interface construction, and the applicable corrosion test method, exposure duration, and pass criteria.

For bid evaluation and site acceptance, request:

• model-specific data sheet and dimensional drawing with groove identification;

• conductor material, construction, cross-section, and diameter matrix for both sides;

• installation instruction, tightening torque, tolerance, and bolt sequence;

• material certificates and hardware/coating specification;

• electrical, mechanical, thermal, short-circuit, and corrosion reports required by the project specification;

• inspection plan, certificate of conformity, batch identification, and routine-test records.

Using CONWELL PG Clamp Data Without Over-Specifying

CONWELL’s public PG clamp range lists APG and CAPG families with a displayed 16–300 mm² range and M8/M10 bolt options. The APG product page identifies the APG family for aluminum conductors. These family-level details are useful for an initial shortlist, but they do not confirm every conductor pair, groove assignment, bolt count, torque, ampacity, or test requirement. Put the exact run/tap schedule in the enquiry and ask CONWELL to return a model-by-model compliance table.

PG Clamp RFQ Checklist

• Connection purpose and system voltage.

• Run conductor: metal, type, cross-section, diameter, stranding, and surface condition.

• Tap conductor: the same complete set of fields.

• Bare, covered, or insulated status and required preparation or resealing.

• Required current, fault duty, temperature rise, resistance, and mechanical performance.

• Preferred bolt quantity only if prescribed; otherwise request supplier selection with evidence.

• Torque value, tolerance, sequence, tools, and installation record format.

• Environment, corrosion test, documentation, quantity, delivery location, and schedule.

Frequently Asked Questions

Can an aluminum PG clamp connect aluminum to copper?

Only if that exact model is explicitly approved for the Al-Cu pair. The normal purchasing direction is a purpose-designed bimetal connector with identified aluminum and copper grooves.

Is conductor cross-section enough for selection?

No. Verify conductor type and actual outside diameter as well. Different constructions with the same cross-section can fit the groove differently.

Does a three-bolt clamp always perform better than a two-bolt clamp?

No. Bolt count affects geometry and pressure distribution, but performance must be shown by model-specific electrical and mechanical data.

Can the installation torque be selected from bolt diameter?

No. Use the torque, tolerance, and sequence issued for the exact clamp model. Bolt diameter alone does not account for clamp geometry, material, lubrication, or hardware condition.

Should installers tighten a PG clamp again later?

Only when the manufacturer’s instruction or the utility maintenance procedure requires it. Uncontrolled re-torque can over-stress the conductor or hardware.

What should be recorded after installation?

Record pole or equipment location, circuit, clamp model and batch, both conductor descriptions, preparation method, compound, torque tool ID and calibration status, final tightening result, installer, date, and inspection photographs.

Request a Model-Matched PG Clamp Proposal

Send CONWELL the run and tap conductor schedule, connection purpose, electrical and mechanical duties, environment, quantity, and required reports. Use the technical enquiry form to request a model selection, drawing, conductor matrix, torque instruction, and document list for bid review.