3G2.5 3-Core 2.5mm² Cable – Predictable Power Delivery, Without the Field Failures

A lighting circuit trips on a newly commissioned floor. An installation crew wastes hours tracing a fault that leads back to a cable with a broken earth continuity. The rework cost isn’t just the wire. It’s the schedule delay, the access equipment, and the compliance re-test.

The 3G2.5 3-core 2.5mm² cable removes that variability. It is built for fixed installations where a dedicated earth path is non-negotiable. Three conductors, one integrated circuit protective conductor included as standard. No separate earth pulling, no mismatched cores. It keeps small-power and lighting circuits running within thermal limits and simplifies termination on site. Supply chain consistency matters too. We stock this cable in depth, ready for cut-to-length orders with no minimum quantity on standard factory packaging.

A cable built around three practical constraints: heat, space, and slack time

Integrated earth conductor (3G configuration)

[Feature]: Three cores, with the third acting as the circuit protective conductor as part of the cable assembly.
[Advantage]: Eliminates the need to run a separate earth wire or rely on steel conduit for the fault path.
[Benefit to your project]: Fewer materials to manage on site. Faster rough-in for lighting and socket circuits. Lower total installed cost when labour is the dominant variable.

2.5mm² copper cross-section, optimized for moderate-current fixed wiring

[Feature]: Class 1 or Class 2 stranded plain copper conductor, 2.5mm² nominal section.
[Advantage]: Manages current-carrying capacity in the range required for 16A–20A radial circuits under common installation methods, without excessive voltage drop on runs up to 30–40 metres.
[Benefit to your project]: One cable SKU covers a wide band of residential, commercial, and light-industrial branch circuits. You avoid over-specifying 4mm² cable and creating unnecessary material cost or stiff routing difficulties in tight containment.

Robust insulation system for dry and damp environments

[Feature]: PVC insulation and bedding compound rated for continuous conductor temperatures up to 70°C (typical).
[Advantage]: Adequate dielectric strength and mechanical protection for installations in conduit, trunking, and clipped direct applications where moisture is intermittent.
[Benefit to your project]: No immediate degradation in basements, plant rooms, or under screed when installation practices follow local wiring rules. Fewer warranty callbacks related to insulation breakdown in standard indoor conditions.

Consistent outer dimensions for predictable pulling and glanding

[Feature]: Controlled overall diameter with low tolerance variation across production batches.
[Advantage]: Installers develop a repeatable muscle memory for stripping, terminating, and sealing cables with matching glands.
[Benefit to your project]: Speed of installation increases when crews work on repeat floor plates. The cable fits pre-cut conduit and knockout sizes reliably. No field modifications needed because the last batch measured slightly different.

Factory-direct volume supply, no intermediary stock splits

[Feature]: Single-source production from extrusion to coiling, packaged at the factory.
[Advantage]: You receive cable from one production run, not multiple batches consolidated by a trader.
[Benefit to your project]: Consistent conductor colour coding, insulation thickness, and surface finish across your entire order. Lower risk of partial rejects when projects demand upfront type-test documentation for the whole lot.

Technical Specifications & Dimensions

The table below captures what the designation “3G2.5” defines and what can be stated without confabulating a specific manufacturer’s datasheet. For a complete engineering drawing, outer diameter tolerance, and full electrical characteristics under your installation conditions, request the batch-specific test report.

Any field blank or marked “confirm” represents a parameter that varies based on the specific standard adopted (IEC, BS, VDE, etc.) and customer order profile. Specifications are provided in full upon RFQ.

Industry Applications & Scenario Validation

• Commercial building lighting circuits – Runs between distribution boards and luminaires in office towers, retail, and education projects. The integrated earth core directly connects metal luminaire bodies, meeting earthing requirements without additional single-core green/yellow wiring.
• Residential high-rise electrical rough-in – Clipped direct or in concealed conduit for socket outlets and fixed appliance spurs. The 2.5mm² section is a standard spec for 20A radial socket circuits across many national wiring codes.
• Industrial machine auxiliary power – Control panel to motor fan units, status indicators, and peripheral devices where running a 4mm² cable would be oversized and harder to terminate in DIN-rail connectors.
• Temporary site distribution – Portable power boxes supplying small tools and lighting on construction sites. The 3G configuration ensures the supply cable carries its own protective earth, a strict safety requirement in site distribution standards.
• Refurbishment and retrofit – Older buildings where the existing containment cannot accommodate thick diameter power cables. The compact dimensions of 3G2.5 simplify pulling through legacy conduit and trunking without upgrading the entire containment system.

International Compliance & QA Standards

Compliance claims are always tied to a specific production batch and the standard selected at order. The checklist below outlines the framework we normally operate within. Let us know which marks or paperwork your project acceptance requires.

• ✅ IEC 60227 (for PVC-insulated cables of rated voltages up to 450/750 V) – relevant type designation mapped to this construction
• ✅ IEC 60332-1 flame propagation test for single cables
• ✅ RoHS (Restriction of Hazardous Substances) – conductor, insulation, and sheath materials
• ✅ CE marking – under applicable Low Voltage and Construction Products directives where relevant
• ✅ ISO 9001 quality management system – applied from incoming copper rod inspection to final spark testing
• ✅ Factory production control (FPC) documentation available for CPR (EU) related applications upon request

FAQ

We are ordering 3G2.5 for a 20A radial circuit with a 35-metre run inside insulated wall cavities. Should we derate and move up to 4mm²?
That depends on the installation method and ambient temperature, not just the length. In thermal insulation, the current-carrying capacity of 2.5mm² can drop below 20A. Run the derating factors from your local wiring rules before switching size. If the calculation shows marginal capacity, 3G2.5 still works when the breaker is sized appropriately. If the load regularly runs near 20A for long periods, going to 4mm² is a thermal decision, not a voltage-drop one. We can supply both sizes—what matters is the engineer’s sign-off on the final circuit design.

What is the outer diameter? We need to check if it fits 20mm conduit with existing circuits.
An exact OD number without knowing whether the cable has a solid or stranded conductor would be misleading. Typical 3G2.5 with PVC insulation and sheath falls in the 8–11 mm range. Give us the conductor class and sheath type you need, and we’ll send the real batch dimension. For conduit fill calculations, always use the actual OD from the factory datasheet, not a catalogue estimate.

Do you supply it with LSZH (low smoke zero halogen) sheath for a hospital project?
Yes. LSZH compound sheathing is available on request. This changes the cable’s thermal rating, abrasion properties, and bending behaviour slightly compared to standard PVC. If your specification calls for LSZH, tell us the exact standard reference and we’ll quote the matched construction. For hospital areas without specific fire performance requirements, standard PVC is often still used where cost and availability are constraints.

Start with the cable, finish with the paperwork

You need 3G2.5 on site, on schedule, with the right test reports attached. Send us your project specification or the applicable national wiring standard. We’ll confirm the cable construction, cut lengths, packing, and lead time within one working day. Request a sample, quote, or full datasheet: [Insert Contact Link / Email / Form CTA].