BS 6004 / BS 6231
British standard building wire for East Africa and the Gulf.
BS 6004 is the British Standard for PVC insulated cables for voltages up to 300/500V. BS 6231 is the switchgear and controlgear wiring cable standard at 600/1000V. Both are specified across East Africa (Kenya, Tanzania, Uganda, Ethiopia), the Gulf States, and in projects built to UK specifications. India's IS 694:2010 was derived from British Standards — the technical distance is the smallest of all international equivalents.
IS 694:2010 evolved directly from British Standards. The insulation, conductor, and test requirements are technically identical.
India adopted British cable standards at independence, and IS 694:2010 is a direct lineage from the original British PVC cable specifications. The insulation compound (TI1 PVC), conductor classes (IEC 60228 Class 1, 2, and 5), and test methodology are the same. IS 694:2010 is rated at 650/1100V against BS 6004 6491X at 450/750V — and uses the same 2.5kV proof test. The voltage class is more conservative on the same physical construction.
BS 6004 and BS 6231 — what each covers and the harmonised equivalents.
| UK Cable Code | British Standard | Harmonised Code | IS 694:2010 Equivalent | Voltage |
|---|---|---|---|---|
| 6491X (solid) | BS 6004 / BS EN 50525-2-31 | H07V-U | FR Single Core Wire — Class 2 | 450/750V |
| 6491X (stranded) | BS 6004 / BS EN 50525-2-31 | H07V-R | FR Single Core Wire — Class 2 | 450/750V |
| 6491X (flexible) | BS 6004 / BS EN 50525-2-31 | H07V-K | Single Core Flexible — Class 5 | 450/750V |
| 2491X (solid) | BS 6004 / BS EN 50525-2-31 | H05V-U | FR Single Core — lighter | 300/500V |
| 6231Y / Tri-rated | BS 6231 | — | Single Core Flexible — Class 5 | 600/1000V |
High-Demand British Standard Specifications
These sizes represent the primary volume drivers for UK and East African residential and industrial projects.
1.5 mm² 6491X (Singles)
Standard: BS 6004 Table 4a.
· Conductor: Class 1 (solid) or Class 2 (stranded)
· R at 20°C: 12.1 Ω/km
· Common use: Conduit-protected lighting and power circuits.
2.5 mm² 6242Y (Twin & Earth)
Standard: BS 6004 Table 8.
· Construction: Flat PVC with bare CPC (earth).
· Current (Method C): 27A
· Common use: Kenya/UK domestic ring mains and sockets.
Manufacturing Capability: The BS Family Gallery
National Cables provides conforming builds for the four primary British Standard cabling methods.
Rigid conduit wire
Flat residential cable
Meter tails
105°C panel wire
The most commonly specified BS 6004 cable — conduit wire for building installation.
| Parameter | Specification |
|---|---|
| Standard | BS 6004:2012+A1:2020 Table 4a · BS EN 50525-2-31 · Harmonised code H07V-U/R |
| Voltage rating | 450/750V |
| Conductor | Plain annealed copper · Class 1 solid (6491X solid) or Class 2 stranded · BS EN 60228 |
| Insulation | PVC Type TI1 — per BS EN 50363-3 |
| Max conductor temperature | 70°C continuous · 160°C short circuit |
| Test voltage | 2.5kV AC (1 min) |
| Flame retardant | IEC 60332-1-2:2004 |
| UK certification body | BASEC (British Approvals Service for Cables) |
Insulation thickness and conductor resistance from BS 6004:2012+A1:2020 Table 4a.
| Size (mm²) | Class | Insulation specified (mm) | OD lower (mm) | OD upper (mm) | Max R at 20°C (Ω/km) |
|---|---|---|---|---|---|
| 1.5 | 1 (solid) | 0.7 | 2.6 | 3.2 | 12.1 |
| 1.5 | 2 (stranded) | 0.7 | 2.7 | 3.3 | 12.1 |
| 2.5 | 1 | 0.8 | 3.2 | 3.9 | 7.41 |
| 2.5 | 2 | 0.8 | 3.3 | 4.0 | 7.41 |
| 4 | 1 | 0.8 | 3.6 | 4.4 | 4.61 |
| 4 | 2 | 0.8 | 3.8 | 4.6 | 4.61 |
| 6 | 1 | 0.8 | 4.1 | 5.0 | 3.08 |
| 6 | 2 | 0.8 | 4.3 | 5.2 | 3.08 |
| 10 | 2 | 1.0 | 5.4 | 6.5 | 1.83 |
| 16 | 2 | 1.0 | 6.3 | 7.6 | 1.15 |
| 25 | 2 | 1.2 | 8.0 | 9.6 | 0.727 |
| 35 | 2 | 1.2 | 9.2 | 11.0 | 0.524 |
Source: BS 6004:2012+A1:2020 (Tables 4a/7/8) and BS 6231. Dimensional data and weights cross-verified against UK project standards. MTO builds include sequential meter marking and custom project-specific inkjet strings for East African tender compliance.
Tri-Rated (BS 6231) and LSZH (BS 7211)
Tri-Rated Panel Wire
High-flexibility Class 5 wire manufactured to conform to BS 6231 (Type CK), UL 1015, and CSA TEW standards. Rated at 105°C for switchgear internal wiring.
6491B LSZH Singles
The Low Smoke Zero Halogen equivalent of 6491X. Manufactured to conform to BS 7211 for public buildings and hospitals where fire safety is paramount.
Rated current — BS 7671:2018+A2:2022 Table 4D1A, 30°C ambient.
Per BS 7671:2018+A2:2022 Table 4D1A (70°C thermoplastic single core). Ambient temperature 30°C. Values apply directly to IS 694:2010 FR single core wire — same conductor, same insulation, same temperature rating.
| Size (mm²) | Method A Conduit in insulated wall | Method B Conduit on wall/trunking | Method C Clipped direct | Method F Free air / cable tray | Max R Ω/km | ||||
|---|---|---|---|---|---|---|---|---|---|
| 2-cable 1φ A | 3/4-cable 3φ A | 2-cable 1φ A | 3/4-cable 3φ A | 2-cable 1φ A | 3/4-cable 3φ A | Horiz. | Vert. | ||
| 1.5 | 14.5 | 13.5 | 17.5 | 15.5 | 20 | 18 | - | - | 12.1 |
| 2.5 | 20 | 18 | 24 | 21 | 27 | 25 | - | - | 7.41 |
| 4.0 | 26 | 24 | 32 | 28 | 37 | 33 | - | - | 4.61 |
| 6.0 | 34 | 31 | 41 | 36 | 47 | 43 | - | - | 3.08 |
| 10.0 | 46 | 42 | 57 | 50 | 65 | 59 | - | - | 1.83 |
| 16.0 | 61 | 56 | 76 | 68 | 87 | 79 | - | - | 1.15 |
| 25.0 | 80 | 73 | 101 | 89 | 114 | 104 | 146 | 130 | 0.727 |
| 35.0 | 99 | 89 | 125 | 110 | 141 | 129 | 181 | 162 | 0.524 |
| 50.0 | 119 | 108 | 151 | 134 | 182 | 167 | 219 | 197 | 0.387 |
| 70.0 | 151 | 136 | 192 | 171 | 234 | 214 | 281 | 254 | 0.268 |
| 95.0 | 182 | 164 | 232 | 207 | 284 | 261 | 341 | 311 | 0.193 |
| 120.0 | 210 | 188 | 269 | 239 | 330 | 303 | 396 | 362 | 0.153 |
| 150.0 | 240 | 216 | 300 | 262 | 381 | 349 | 456 | 419 | 0.124 |
| 185.0 | 273 | 245 | 341 | 296 | 436 | 400 | 521 | 480 | 0.0991 |
| 240.0 | 321 | 286 | 400 | 346 | 515 | 472 | 615 | 569 | 0.0754 |
Ambient temperature correction — 70°C PVC.
Values above at 30°C ambient. Multiply the tabulated rating by the factor for your site ambient temperature.
Per BS 7671:2018+A2:2022 Table 4B1. Example: 10mm² clipped direct at 45°C ambient in Nairobi or Dubai: 65 × 0.79 = 51A.
Where British Standards are specified.
The IS 694:2010 products BS 6004 and BS 6231 orders are fulfilled from.
BS 6004 and BS 6231 British Standard wire — technical questions answered.
Common questions from UK project consultants, East African EPC contractors, Gulf region panel builders, and Commonwealth-specification buyers selecting BS-specification cable manufactured in India.
What is 'Tri-rated' cable and why is it associated with BS 6231?
Tri-rated cable is a flexible single-core panel wire manufactured to meet the requirements of three standards simultaneously:
BS 6231 (British Standard for switchgear/controlgear wiring, 600/1000V)
UL 1015 (US flexible panel wire)
CSA 22.2 (Canadian equivalent)
National Cables manufactures panel wire Tri-rated conformant — meaning the construction meets the technical requirements of BS 6231 and is compatible with tri-rated specification language.
Our products are not individually UL- or CSA-listed; for projects requiring the UL/CSA mark, confirm requirements at the enquiry stage.
What is the difference between BS 6004 and BS 6231?
BS 6004 covers PVC insulated and sheathed cables for domestic and light commercial building wiring up to 300/500V — typical products include twin-and-earth, 6181Y meter tails, and 6242Y flat cable.
BS 6231 specifies single-core PVC-insulated flexible cables for switchgear, control gear, and instrument panel wiring at 600/1000V.
BS 6231 is the correct standard for internal panel wiring; BS 6004 is for domestic and commercial building circuits. National Cables manufactures to both BS 6004 and BS 6231 specifications on BIS-certified production lines.
What is the difference between BS 6231 Type BK and Type CK?
Both are single-core Class 5 flexible copper cables to BS 6231, differing in PVC compound and maximum operating temperature.
Type BK uses standard PVC compound Type TI1 rated for 70°C maximum conductor temperature.
Type CK uses heat-resistant PVC compound Type TI3 rated for 90°C maximum conductor temperature — the CK variant is used for Tri-rated conformant construction because the higher temperature rating supports UL/CSA 105°C requirements alongside BS 6231's 90°C.
Select CK for higher-temperature panel environments or tri-rated applications.
Can Tri-rated wire handle 105°C?
The 105°C rating applies when cable is individually UL 758 or CSA 22.2 approved. BS 6231 alone specifies 90°C maximum continuous conductor temperature for Type CK.
National Cables manufactures Tri-rated conformant panel wire to BS 6231 Type CK — meaning the physical construction is designed to also meet 105°C tri-rated specifications — but our products are not individually UL-listed or CSA-approved.
For projects requiring the 105°C rating with UL/CSA certification marks, confirm your certification requirement during enquiry.
Are BS 6231 and BS 6004 cables flame retardant?
Yes. Cables manufactured to BS 6231 and BS 6004 are tested and compliant with IEC 60332-1-2 — the single-cable vertical flame propagation test confirming the cable self-extinguishes after flame source removal. This is a standard requirement for both British Standards and is part of routine type testing.
For multi-cable bundled flame testing (IEC 60332-3 series, for risers and cable trays), specific compliance should be confirmed from the product test certificate, as IEC 60332-3 is typically applied to HFFR/LSZH cables rather than PVC panel wire.
Is National Cables BASEC certified for BS 6004 / BS 6231?
No. National Cables does not hold BASEC certification. Our BS 6004 and BS 6231 cables are manufactured to the British Standard specification on BIS-certified production lines in India — we use the language "BASEC-conformant manufacturing" or "manufactured to BS 6004 / BS 6231" to describe our products accurately.
For UK projects requiring the BASEC mark specifically, please clarify this requirement at the enquiry stage. We provide full BIS test certificates, CE declaration, and BS specification conformance documentation with every shipment.
Enquire for BS 6004 / BS 6231 conforming supply.
East Africa, Gulf, and UK project specifications — technical equivalence documentation and competitive export pricing.