BS 5467 vs BS 6724 for External Lighting: Which Armoured Cable Standard Should You Specify?

📅 Published: 2026-06-12 | 📁 Category: Armoured Cable Guide | ⏱ 12 min read

1. Why the Right Cable Standard Matters for External Lighting

Specifying the wrong cable for an outdoor lighting installation is not just a paperwork error — it can mean early sheath degradation, fire safety non-compliance, unnecessary cost overruns, or failing a building control inspection. In the UK, the two dominant British Standards for low-voltage armoured power cables — BS 5467 and BS 6724 — are often treated as interchangeable. They are not.

Both standards describe cables with XLPE insulation, steel wire armour (SWA), and a 600/1000V rating. Both are suitable for direct burial. Both share the same current-carrying capacities and physical dimensions. The critical difference is the outer sheath material: PVC under BS 5467, and LSZH (Low Smoke Zero Halogen) under BS 6724.

For an external lighting contractor or consultant, the choice between these two standards depends on a single question: where does the cable terminate? If it never enters a building or enclosed space, BS 5467 is cost-effective and field-proven. If it passes through a fire-sensitive area — a plant room, a public building, a tunnel, or a school — BS 6724's LSZH sheath becomes a fire safety requirement, not a preference.

This guide provides a side-by-side comparison of BS 5467 and BS 6724 for external lighting applications, including construction differences, fire performance, cost impact, installation requirements under BS 7671, and practical decision criteria for UK electrical contractors and specifiers.

2. Construction: Same Core, Different Sheath

BS 5467 and BS 6724 cables share the same conductor, insulation, and armour construction. Every difference is in the bedding and outer sheath materials.

2.1 Common Construction — Copper Conductor & XLPE Insulation

Both standards specify plain annealed stranded copper conductors to BS EN 60228 (Class 2), with XLPE (cross-linked polyethylene) insulation to BS 7655 Type GP8. XLPE provides a 90°C maximum conductor operating temperature and 250°C short-circuit capability — significantly higher than PVC-insulated cables (70°C).

2.2 Armour — Steel Wire Armour (SWA)

Both use a single layer of galvanised steel wire armour for mechanical protection. For single-core cables, aluminium wire armour (AWA) is required instead to avoid inductive heating. The armour also serves as a Circuit Protective Conductor (CPC) under BS 7671 when correctly terminated at both ends.

2.3 The Critical Difference: Bedding & Outer Sheath

2.4 Identical Electrical Performance

Because the conductor, insulation thickness, and armour are identical, both cable types share the same:

• Current-carrying capacity (ampacity) — per BS 7671 Table 4E4A
• Voltage drop (mV/A/m) — identical per core size
• Short-circuit rating — 250°C for 5 seconds
• Overall dimensions — same outer diameter per conductor size
• Minimum bending radius — 6× OD for ≤16 mm², 8× OD for ≥25 mm²

2.5 Pricing: BS 5467 vs BS 6724 at SORIVO

3. Standards & Certification: What BS 5467 and BS 6724 Actually Require

Both standards are published by the British Standards Institution (BSI) and are harmonised with European and international standards. Here is what each standard actually specifies and tests.

3.1 BS 5467:2016 — XLPE/SWA/PVC

Full title: Specification for cables with thermosetting insulation for rated voltages up to and including 600/1000V.

• XLPE insulation to BS 7655 Type GP8 — 90°C continuous, 250°C short-circuit
• PVC bedding and outer sheath to BS 7655 Type 9
• SWA or AWA armour per conductor size configuration
• Flame retardancy to IEC 60332-1-2 (single cable vertical flame propagation)
• Voltage rating: U₀/U = 0.6/1 kV (also available in 1.9/3.3 kV)

3.2 BS 6724:2016 — XLPE/SWA/LSZH

Full title: Specification for cables with thermosetting insulation for rated voltages up to and including 600/1000V, having low emission of smoke and corrosive gases when affected by fire.

• Same XLPE insulation as BS 5467 (BS 7655 Type GP8)
• LSZH bedding and sheath to BS 7655 Type LTS1 — zero halogen, low smoke
• Flame retardancy to IEC 60332-1-2 plus IEC 60332-3-24 Cat C (bunched cables)
• Halogen-free to IEC 60754-1/2 — HCl content < 0.5%
• Low smoke to IEC 61034-2 — light transmittance ≥ 60%
• Voltage rating: U₀/U = 0.6/1 kV (also available in 1.9/3.3 kV)

3.3 BS 7671 (IET Wiring Regulations) — External Lighting Requirements

The 18th Edition of BS 7671 sets the following requirements relevant to external lighting cable selection:

4. Which Standard for Which External Lighting Scenario?

The decision between BS 5467 and BS 6724 depends on the cable route and the building types it serves. The following table gives scenario-based recommendations.

4.1 Application Decision Table

4.2 BS 5467 vs BS 6724 — Equivalent Cable Sizes & Ampacity

Ampacity per BS 7671 Table 4E4A; voltage drop per Table 4E4B. 3-core cable at 90°C conductor temperature, 30°C ambient. Current ratings are identical between BS 5467 and BS 6724 for the same conductor size.

5. The 25-Year Cost: BS 5467 vs BS 6724 in External Lighting

The upfront cost difference between BS 5467 and BS 6724 is typically 10–15%. But the total cost of ownership tells a different story — especially when fire risk, replacement cycles, and compliance penalties are factored in.

5.1 When BS 5467 (PVC) Costs More Over Time

If PVC-sheathed cable is installed where LSZH is now required by Code or local regulation — for example, in a school extension where the cable enters a fire compartment — the eventual remediation cost far exceeds the upfront saving.

5.2 Typical Cable Cost Comparison (per metre, 4-core 6 mm² SWA)

5.3 The Compliance Cost of Getting It Wrong

A Building Control inspection that finds PVC-sheathed cable in a fire compartment where LSZH is specified can result in:

• Rejection of the electrical installation — delaying project handover
• Cost of replacement — excavation, re-cabling, making good surfaces
• Reputational risk — for the contractor and consultant
• Potential insurance implications — non-compliant installation may affect coverage

6. How to Verify BS 5467 / BS 6724 Cable Quality Before Purchase

When sourcing armoured cable for an external lighting project, use these practical checks to confirm you are getting the standard you specified.

1. Read the cable marking: Every metre of compliant BS 5467 or BS 6724 cable must be marked with the standard number, conductor size, voltage rating, and manufacturer (or BASEC licence number). Example: "BS 5467 6mm² 3-Core 0.6/1kV SORIVO". Rub the marking — if it smudges or wipes off, the ink quality is poor.
2. Check the BASEC certificate: BASEC is the UK's leading cable certification body. Every BASEC-certified cable has a unique licence number searchable at www.basec.org.uk. Never rely solely on printed labels — verify the licence is active.
3. Burn test (simple field check): Take a small offcut of the outer sheath. Heat it with a lighter in a ventilated area. PVC produces black smoke and a sharp chlorine smell (like bleach). LSZH produces minimal white/grey smoke, no chlorine smell, and the material leaves a chalky residue rather than dripping.
4. Measure outer diameter: Compare against the manufacturer's datasheet. A cable that is significantly thinner than specified may have reduced XLPE insulation thickness or fewer armour wires — both safety-critical issues.
5. Check conductor stranding: For a 6 mm² cable, expect Class 2 stranded copper — typically 7 wires (1+6 construction). If the conductor has fewer or visibly thinner strands, the cable may not meet BS EN 60228.
6. Sheath flexibility: PVC stiffens noticeably at low temperatures (below 0°C). LSZH Type LTS1 maintains flexibility across a wider temperature range. If the cable feels unusually stiff in cold weather, compare against a known compliant sample.

For a complete walkthrough, see our dedicated guide: How to Verify Cable Certification (methodology applies equally to BS standards).

7. Conclusion: A Practical Framework for Specifying External Lighting Cable

When specifying armoured cable for external lighting, follow this three-step process:

1. Map the cable route — does it enter any building, fire compartment, tunnel, or enclosed public space? If yes, BS 6724 (LSZH) is required. If entirely outdoors, BS 5467 (PVC) is sufficient.
2. Size the cable — use the ampacity values in BS 7671 Table 4E4A. Remember: BS 5467 and BS 6724 have identical current ratings for the same conductor size. Verify voltage drop for long runs (over 80 metres).
3. Specify the standard clearly — write "BS 6724 4-core 6 mm² XLPE/SWA/LSZH" in your bill of quantities. Do not write "or equivalent" unless you verify the proposed substitute carries the same fire performance certification.

For the majority of external lighting applications — street lighting, car parks, sports floodlighting — BS 5467 XLPE/SWA/PVC remains the industry standard: reliable, cost-effective, and fully compliant with BS 7671 for outdoor use.

For any installation where the cable enters a building or serves a fire-sensitive environment, BS 6724 XLPE/SWA/LSZH is not a premium upgrade — it is a safety requirement. At SORIVO, both standards are available with full BASEC certification and batch traceability.

Further reading:

• SWA vs AWA vs STA Armoured Cable | BS 5467/BS 6724 Comparison
• Cable Laying Methods & Requirements — Direct Burial, Duct, Trench & Tray
• Industrial Cable Selection Guide | Conductor, Insulation & TCO
• CU/XLPE/SWA/PVC 0.6/1kV — BS 5467 Armoured Power Cable
• CU/XLPE/LSZH/SWA/LSZH 0.6/1kV — BS 6724 Armoured Power Cable

8. Frequently Asked Questions