Bottom line: select in three steps — voltage rating first, then installation environment, then fire performance. Building wiring up to 450/750V goes to BS 6004 (PVC) or BS 7211 (LSZH); 600/1000V distribution with mechanical risk or direct burial goes to armoured BS 5467; fire alarm and emergency circuits go to BS 7629-1 / BS 5839-1; marine and offshore go to BS 6883 / BS 7917; mining trailing goes to BS 6708; 11~33kV distribution goes to BS 7870-4.10.
Suffix decoder: X / Y = PVC (2491X, 6491X, 6181Y); B = LSZH (2491B, 6491B, 6181B, 6381B); TQ = HOFR rubber sheath (6381TQ = H07BN4-F). The last letter of the code already tells you half the material system.
Three-step selection
| Step | Decision point | Standard to specify |
|---|---|---|
| ① Voltage | ≤300/500V final circuits | BS 6004 / BS 7211 / BS 8436 / BS 7629-1 |
| 450/750V | BS 7211 (6181B, 6381B), BS 7919 flexible rubber | |
| 600/1000V distribution, direct burial | BS 5467 (PVC armoured) / BS 6724 (LSZH armoured) | |
| 11~33kV medium voltage | BS 7870-4.10 | |
| ② Environment | Buried in walls / cavities at depth <50mm | BS 8436 (metallic screen + 6 nail penetration tests) |
| Ships, offshore platforms | BS 6883; add BS 7917 (F0/F1) for fire survival | |
| Mining, trailing, shearer loaders | BS 6708 | |
| Direct connection to motor / transformer windings | BS 6195 | |
| ③ Fire | Fire alarm, emergency lighting | BS 7629-1 (minimum PH30); Enhanced = 120 min |
| Public areas, critical escape routes | LSZH family (BS 7211 and "B"-suffix types) |
Standard comparison table
| Standard | Cable type | Rated voltage | Construction | Typical use |
|---|---|---|---|---|
| BS 5467 | XLPE insulated, PVC sheathed armoured power cable | 600/1000V | Multi-core galvanised steel wire armour, non-magnetic aluminium wire armour for single-core; conductor 90℃ continuous / 250℃ short circuit; 1~5 cores (auxiliary up to 48) | Industrial fixed wiring, distribution; direct burial in well-drained soil or concrete |
| BS 6004 | PVC insulated, PVC sheathed wiring cable | ≤300/500V | Includes flat Twin & Earth, 6181Y; Arctic grade 318-A down to -40℃ | Final circuits and lighting in homes and light industry |
| BS 7211 | Thermoset insulated, thermoplastic sheathed low-smoke low-corrosion cable | ≤450/750V | Far less smoke and corrosive gas than PVC in fire; includes 6242B, 6181B, 6381B | Where smoke toxicity matters |
| BS 7919 | Harmonised flexible rubber cable family | 300/500V or 450/750V | HOFR type 6381TQ (=H07BN4-F) heat/oil/flame resistant; H07ZZ-F reduced toxic smoke | Mobile power supply, industrial flexible connections |
| BS 5839-1 | Fire detection and alarm systems (defines cable fire grades) | — | Two grades: Standard (PH30) and Enhanced (120 min) | Fire alarm and emergency evacuation systems |
| BS 7629-1 | Screened fire-resistant multicore / multipair cable | 300/500V | Tinned annealed copper; metallic or laminated screen; LTS 3 sheath; HCl ≤0.5%; minimum PH30 | Emergency lighting, fire alarm circuits |
| BS 8436 | Metallic screened cable for walls and cavities | 300/500V | 2/3/4 cores plus full-size uninsulated circuit protective conductor; must pass 6 nail penetration tests | Building cavities, partitions, buried at depth <50mm |
| BS 6883 | Elastomer insulated marine cable | 150/250V ~ 8.7/15kV | Tinned annealed copper; G4/GP4/GP5 insulation; steel/copper/bronze braid; SW2/SW3/SW4 sheath | Ships, offshore platforms, drilling rigs |
| BS 7917 | Fire-resistant marine cable | ≤3.3kV | As BS 6883 plus mica tape; F0 = 750℃ for 3h, F1 = 950℃ for 3h | Circuits that must survive fire offshore |
| BS 6708 | Flexible trailing cable for mining | 320/550V ~ 3.8/6.6kV | Heavy-duty flexible rubber, many types with galvanised steel wire armour; Types 7/11/20/21/62/63/64/201/211/307/321/331/506 etc. | Shearers, excavators, crushers, mine roadway lighting |
| BS 6195 | High-flexibility winding / panel wiring cable | Categories A~F, 90℃ | Flame-retardant flexible Type 4; resistant to oil-based lubricants, solvents, varnishes | Direct permanent connection of motors, generators, transformers, circuit breakers |
| BS 7870-4.10 | Medium voltage single-core extruded distribution cable | 11~33kV | Class 2 annealed copper / solid or hard aluminium; XLPE or EPR; semiconductive screen plus copper wire metallic screen; MDPE sheath; red at 11kV, black at 33kV | DNO distribution networks, underground service entries; not for overhead supply |
Related references: BS 6724 is the LSZH alternative to BS 5467; BS 7846 is armoured fire-resistant cable; BS 638 covers welding cable (H01N2-D/E); BS 6500 covers flexible PVC appliance cord (H03VV-F/H05VV-F); BS 7671 is the wiring regulations. Note that BS 7870 appears in sources as both 19~33kV and (clause 4.10) 11~33kV — always confirm against the current standard text before ordering.
Fire performance: PH30 is a floor, not a default
| System | Grade | Requirement |
|---|---|---|
| BS 5839-1 | Standard | PH30 to BS EN 50200 — circuit integrity ≥30 min under flame, mechanical shock and water spray |
| BS 5839-1 | Enhanced | Circuit integrity ≥120 min |
| BS 7629-1 | Minimum PH30 | 15 min fire + shock, then 15 min fire + shock + water; Enhanced types add mica tape and a glass barrier |
| BS 7917 | F0 / F1 | 750℃ / 950℃ fire survival for 3 hours |
When Enhanced is typically required: unsprinklered buildings with an evacuation strategy of four or more stages; unsprinklered buildings over 30m in height; unsprinklered sites where one fire could affect critical signal-path cables far from the fire zone while people remain active; and anywhere the designer, specifier or regulator's risk assessment calls for enhanced performance.
Five costly mistakes when supplying BS cables to UK projects
- Third-party approval is not self-declaration. UK projects commonly require BASEC, LPCB or Lloyd's Register product approval — confirm which body the specification names before quoting.
- Shallow burial needs BS 8436. Where cables are buried less than 50mm without mechanical protection, BS 7671:2008(2011) clauses 522.6.100~103 call for a cable that survives nail penetration; standard T&E or 6181Y will be rejected.
- Do not quote BS 5467 for an LSZH armoured requirement. BS 5467 has a PVC sheath; the low-smoke halogen-free armoured equivalent is BS 6724.
- Set the fire grade from BS 5839-1 first — decide Standard (PH30) versus Enhanced (120 min) before pricing, instead of defaulting to the minimum.
- Medium voltage cable is not for overhead. BS 7870-4.10 is intended for underground service entries and distribution networks, explicitly not for overhead supply.
Key types at a glance
| Type | Standard | Key parameters | Application |
|---|---|---|---|
| 6381B | BS 7211 / IEC 60502-1 | LSZH, 0~+90℃, blue / grey / green-yellow | DC power supply for telecom equipment and flexible electrical use |
| 6181B | BS 7211 | Single core, double insulated, 1.5~300mm², 450/750V, white sheath, BASEC approved | Meter control circuits, fixed wiring in homes and light industry |
| 2491B | Harmonised LSZH (H05Z-K/H07Z-K) | Flexible LSZH; PVC equivalent is 2491X (H05V-K/H07V-K) | Internal appliance wiring, indoor wiring in public premises |
| FGT | Enhanced Class 2 power cable | PVC or LSZH sheath, copper or aluminium conductor, black, 10~120mm² | Enhanced power supply circuits |
FAQ
Q1: BS 6004 or BS 7211 — which one do I need? A: Both are building wiring cables; the difference is sheath material and smoke toxicity. BS 6004 is PVC insulated and PVC sheathed (≤300/500V, includes Twin & Earth and 6181Y), fine for ordinary dwellings. BS 7211 is thermoset insulated with a thermoplastic low-smoke low-corrosion sheath (≤450/750V) that releases far less smoke and corrosive gas in a fire. Choose BS 7211 for public premises and critical escape routes.
Q2: The client wants armoured cable with LSZH — can I quote BS 5467? A: No. BS 5467 is XLPE insulated with a PVC sheath, which contains halogens. The low-smoke halogen-free armoured equivalent is BS 6724.
Q3: Is BS 8436 mandatory for cables buried less than 50mm deep? A: Per BS 7671:2008(2011) clauses 522.6.100~103, concealed wiring at shallow depth without mechanical protection needs a cable that resists nail penetration. BS 8436 carries a metallic screen and must pass six nail penetration tests precisely for this case; ordinary T&E or 6181Y will not pass inspection.
Q4: What is the difference between 6381B and 6181B? A: 6381B serves DC power supply for telecom equipment and other applications needing good flexibility, rated 0~+90℃ and commonly supplied in blue, grey or green-yellow. 6181B is a single-core, double-insulated LSZH wiring cable, 1.5~300mm² at 450/750V with a white sheath that stays unobtrusive when surface run, used for meter control circuits and fixed wiring. One is "power plus flexibility", the other is "fixed building wiring".
Q5: Which approvals are normally needed for BS cables on UK projects? A: The standard is the threshold; approval is the passport. UK specifications commonly name BASEC (6181B, for example, is BASEC approved), LPCB, or Lloyd's Register for marine work. Confirm the named body at quotation stage and prepare test evidence to BS EN 60754 (halogen/acid gas), BS EN 61034 (smoke density) and BS EN 60332 (flame propagation).
Chinese version: 英标BS系列电缆选型指南（中文）
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