FR-LSH Single Core Wire — Low Smoke Halogen
FR-LSH wire limits flame spread, smoke density, and halogen acid gas release during a fire. In enclosed public spaces, smoke and toxic gas are the primary hazard before flames. Specified for hospitals, airports, metro stations, hotels, and data centres.
Dimensional & Electrical Data — IS 694:2010 (FR-LS Designation)
FR-LSH wire is rated at 70°C continuous conductor temperature — the same voltage and thermal class as standard FR wire under IS 694:2010. The differentiation is in fire performance: the FR-LSH compound produces significantly reduced smoke density (transmittance >60% per IEC 61034-2), limited halogen acid gas emission (HCl <15% per IEC 60754-1), and a higher Oxygen Index (>29%) than standard FR PVC. National Cables holds valid BIS certification (IS 694:2010) for the complete range from 0.5mm² up to 240mm², ensuring project-level compliance for both residential and industrial infrastructure.
| Cross Section (mm²) | Nominal Insulation Thickness (mm) | Approx. OD (mm) | Current — In Conduit 2-cable 1φ (A) | Current — In Conduit 3-cable 3φ (A) | Current — Clipped Direct 1φ (A) | Current — Clipped Direct 3φ (A) | Current — Open Air / Tray 1-cable (A) | Max DC Resistance at 20°C (Ω/km) |
|---|---|---|---|---|---|---|---|---|
| Standard Range — Stock Items | ||||||||
| 0.5 | 0.6 | 2.25 | 4 | — | 5 | — | — | 39.0 |
| 0.75 | 0.6 | 2.40 | 7 | — | 8 | — | — | 26.0 |
| 1.0 | 0.6 | 2.60 | 11 | 10 | 12 | 11 | 15 | 19.5 |
| 1.5 | 0.7 | 2.90 | 13 | 13 | 16 | 15 | 20 | 13.3 |
| 2.5 | 0.8 | 3.90 | 18 | 17 | 22 | 21 | 27 | 7.98 |
| 4.0 | 0.8 | 4.50 | 24 | 23 | 29 | 28 | 37 | 4.95 |
| 6.0 | 0.8 | 5.30 | 31 | 29 | 37 | 36 | 47 | 3.30 |
| 10.0 | 0.8 | 6.70 | 42 | 40 | 51 | 50 | 65 | 1.91 |
| 16.0 | 1.0 | 8.20 | 57 | 54 | 68 | 68 | 87 | 1.21 |
| 25.0 | 1.0 | 10.00 | 71 | 68 | 86 | 89 | 114 | 0.780 |
| 35.0 | 1.2 | 11.30 | 91 | 87 | 110 | 110 | 141 | 0.554 |
| 50.0 | 1.4 | 13.50 | 120 | 114 | 145 | 134 | 182 | 0.386 |
| Extended Range — Available on Order | ||||||||
| 70.0 | 1.4 | 12.90 | 151 | 143 | 183 | 171 | 234 | 0.272 |
| 95.0 | 1.6 | 15.00 | 182 | 172 | 220 | 207 | 284 | 0.206 |
| 120.0 | 1.6 | 16.60 | 210 | 198 | 253 | 239 | 330 | 0.161 |
| 150.0 | 1.8 | 18.50 | 240 | 226 | 290 | 262 | 381 | 0.129 |
| 185.0 | 2.0 | 20.60 | 273 | 257 | 329 | 296 | 436 | 0.106 |
| 240.0 | 2.2 | 23.20 | 320 | 301 | 386 | 346 | 515 | 0.0801 |
| Current ratings per IS 694:2010 — ambient temperature 30°C. Extended range sizes (70–240mm²) manufactured to order. De-rating factors for ambient temperatures above 30°C apply per IS 3961 (Part 2):2017. | ||||||||
De-rating Factors — FR-LSH 70°C Compound
All current ratings are tabulated at 30°C ambient. Apply de-rating factors for installations where ambient temperature exceeds this reference. FR-LSH PVC insulation is rated to 70°C per IS 694:2010; the de-rating multipliers below still govern installation design for sizing purposes.
| Ambient Temp | Multiply by |
|---|---|
| 25°C | 1.03 |
| 30°C | 1.0 |
| 35°C | 0.94 |
| 40°C | 0.87 |
| 45°C | 0.79 |
| 50°C | 0.71 |
| 55°C | 0.61 |
| 60°C | 0.5 |
| Reference: 30°C ambient. Source: IS 3961 (Part 2):2017. The FR-LSH PVC compound is rated for 70°C continuous operation. For specific high-load calculations at elevated temperatures, contact our engineering cell. | |
Example: 10mm² wire clipped direct = 51A at 30°C. At 45°C ambient: 51 × 0.79 = 40A.
Particularly relevant for industrial buildings, rooftop runs, and locations in North and Central India where summer ambient temperatures regularly exceed 40°C.
Fully vertically integrated manufacturing.
Every FR-LSH single core wire is built through a completely in-house production ecosystem — from copper drawing to FR-LSH compound formulation. The critical difference from standard FR wire is in the insulation compound: our FR-LSH compound is specifically formulated to suppress smoke and limit halogen acid gas evolution during combustion.
What makes FR-LSH the right specification.
Each of these properties is the direct result of our in-house FR-LSH compound formulation — measurable, tested, and documented on every production lot.
Where this wire is specified.
FR-LSH is specified wherever both flame retardancy and occupant safety during a fire event are required. The low smoke and limited halogen properties are mandatory in enclosed public spaces under NBC 2016 and MEP specifications for critical infrastructure.
Standards this product is manufactured to.
National Cables FR-LSH Single Core Wire is manufactured and tested to current Indian and international standards. The compliance framework for FR-LSH includes additional smoke and halogen tests beyond the standard FR requirement. Full documentation available for institutional procurement, government tenders, and export requirements.
FR-LSH single core wire — technical questions answered.
Common questions from MEP consultants, fire safety specifiers, procurement teams, and EPC contractors selecting FR-LSH wire for high-rise, hospital, and commercial infrastructure projects.
Why is FR-LSH wire recommended for commercial complexes and high-rise buildings?
FR-LSH wire reduces smoke density and halogen acid gas emission during combustion compared to standard FR PVC wire. This matters in commercial buildings, hotels, hospitals, shopping malls, and high-rises because more than 80% of fire casualties result from smoke inhalation and visibility loss, not flame contact.
FR-LSH is generally specified as the minimum standard for buildings over 15 metres (approximately four storeys) per National Building Code (NBC 2016) fire safety guidance for enclosed public spaces. Always verify against your local building code and fire consultant's specification.
Does FR-LSH wire meet the IS 694:2010 standard?
Yes. IS 694:2010 covers four cable categories: Category 01 (indoor), Category 02 (outdoor), Category FR (Flame Retardant), and Category FR-LSH (Flame Retardant Low Smoke and Halogen).
FR-LSH is the PVC-based category that uses modified compounds to reduce smoke density and halogen emission — a step above standard FR, but distinct from halogen-free HFFR wire (which is covered separately under IS 17048:2018). National Cables manufactures FR-LSH wire under BIS licence CM/L-8800140116.
What smoke density limit is typical for FR-LSH wires?
FR-LSH wires are formulated so that light transmission during combustion remains greater than 40%, measured per IEC 61034-2 (smoke density test) or equivalent ASTM D 2843 methods. This ensures usable visibility for evacuation in enclosed spaces where standard PVC cables would produce near-total visual obscuration.
Always request the batch-specific test certificate rather than relying on generic claims — actual values vary by compound formulation and should be confirmed from the manufacturer's test report.
What is the acid gas emission percentage for FR-LSH wires?
FR-LSH wire under IS 694:2010 typically limits halogen acid gas (HCl) emission to a maximum of around 20% when tested per IEC 60754-1. This is substantially lower than standard PVC (which can emit 25–30% HCl) but is not "zero halogen." The "low halogen" designation means reduced, not eliminated.
If a project specification requires HCl emission below 0.5%, specify HFFR wire to IS 17048:2018 instead. Confirm exact emission values from the batch test certificate supplied with your order.
Is FR-LSH wire halogen-free or non-toxic?
No. FR-LSH uses a halogen-reduced PVC compound — halogen content is lowered but not eliminated, and the wire cannot be described as "non-toxic" in absolute terms. PVC still contains chlorine, and combustion still produces some acid gas and smoke, just at reduced levels compared to standard PVC.
For fully halogen-free construction (zero chlorine, fluorine, or bromine), specify HFFR / LSZH wire to IS 17048:2018, which uses halogen-free polyolefin insulation and emits HCl below 0.5%.
Request institutional pricing and technical documentation.
Our engineering team responds within 24 hours with accurate bulk pricing, complete compliance documentation, and specifications. BOQ uploads accepted.
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Supplying to an international project?
This wire is manufactured to IS 694:2010 on a BIS-certified production line. The same facility produces cable conforming to equivalent international standards — if your project specifies H07V-U / H07V-R / H07V-K / BS 6004 / BS 6231 / SANS 1507 with low-smoke halogen-reduced requirements, we can supply from the same certified manufacturing facility.