1. What is FRLS Cable? Full Form and Meaning
FRLS full form is Flame Retardant Low Smoke. An FRLS cable is an electrical wire or cable that is engineered with two critical safety properties:
- Flame Retardant (FR): The cable resists the spread of fire along its length. Even if ignited, it self-extinguishes once the fire source is removed.
- Low Smoke (LS): When the cable does burn or smoulder, it produces significantly less smoke and toxic gas compared to conventional PVC cables.
In simple terms, an FRLS wire is designed to buy time during a fire emergency it slows down the fire, keeps escape routes visible with less smoke, and reduces the inhalation of toxic fumes like hydrogen chloride (HCl). This is why FRLS cabling is now mandatory in most high-rise buildings, hospitals, hotels, airports, and public infrastructure projects under Indian building codes and fire safety norms.
Quick Definition: FRLS Cable = Flame Retardant Low Smoke Cable. It is a safety-grade electrical cable that limits fire propagation and minimises toxic smoke emission during a fire incident.
2. How Does FRLS Cable Work?
The performance of an FRLS cable comes from the special compound used in its insulation and outer sheath. Here is how the chemistry works:
2.1 Flame Retardant Compound
Standard PVC insulation in ordinary cables releases chlorine gas and propagates flames easily. FRLS cables use a specially formulated PVC or LSZH (Low Smoke Zero Halogen) compound that contains flame-retardant additives often aluminium trihydrate (ATH) or magnesium hydroxide. These additives release water vapour when heated, which cools the combustion zone and interrupts the fire triangle.
2.2 Low Smoke Emission
The modified sheath compound burns at a higher temperature before breaking down and produces much lower concentrations of smoke particles. Regulatory tests measure smoke density under IEC 61034 (minimum 60% light transmittance during the test), ensuring evacuation routes remain visible.
2.3 Reduced Toxic Gas
Many premium FRLS cables also limit the emission of halogen acids. A cable labelled FRLS-H or ZHFR (Zero Halogen Flame Retardant) provides the highest level of protection critical for data centres, hospitals, and confined public spaces.
3. FRLS Cable vs FR Cable What Is the Difference?
This is one of the most searched questions: "What is the difference between FR and FRLS cable?" Here is a clear side-by-side comparison:
| Parameter | FR Cable (Flame Retardant) | FRLS Cable (Flame Retardant Low Smoke) |
|---|---|---|
| Full Form | Flame Retardant | Flame Retardant Low Smoke |
| Fire Resistance | Yes resists fire propagation | Yes resists fire propagation |
| Smoke Emission | Moderate to high smoke | Low smoke (min. 60% light transmittance) |
| Toxic Gas | Can emit HCl and toxic fumes | Significantly reduced toxic gas emission |
| IS Standard | IS 694 (PVC), IS 7098 | IS 694 with FRLS addendum, IEC 60332, IEC 61034 |
| Cost | Lower | Slightly higher (10–20%) |
| Best For | Low-rise buildings, outdoor conduits | High-rise, hospitals, hotels, metro, airports |
| Mandatory Use | General wiring | Mandated in NBC 2016 & fire safety codes |
Bottom line: If your project requires compliance with the National Building Code (NBC) 2016, fire NOC from local fire departments, or international safety certifications, FRLS cable is the minimum specification you should use not just FR.
4. Types of FRLS Cables
The FRLS category is broad. Here are the main types of FRLS cables available in the Indian and global markets:
4.1 FRLS PVC Insulated Cable
The most widely used type. Features FRLS-grade PVC insulation and sheath. Used for general internal wiring in buildings, panels, and switchboards. Available as single-core, multi-core, and multi-strand variants. Conforms to IS 694.
4.2 FRLS XLPE Cable
Cross-Linked Polyethylene (XLPE) insulated cables with FRLS outer sheath. These offer higher current carrying capacity, better temperature resistance (90°C vs 70°C for PVC), and longer service life. Preferred for HT/LT power distribution in industrial plants and large commercial complexes. Conforms to IS 7098 Part 1 & 2.
4.3 FRLS Armoured Cable
FRLS cables with galvanised steel wire armouring (GSWA) or aluminium wire armouring (AWA). Provides mechanical protection against rodents, crushing, and physical impact. Used for underground or exposed installations where both fire safety and mechanical strength are needed.
4.4 FRLS Flexible Cable / House Wire
Multi-strand flexible conductors with FRLS PVC insulation. This is the standard FRLS house wiring cable used in residential and commercial internal wiring. Comes in sizes from 0.5 sq mm to 6 sq mm and is available in colour-coded variants.
4.5 LSZH / ZHFR Cable (Zero Halogen)
The premium variant. LSZH (Low Smoke Zero Halogen) or ZHFR cables emit zero halogen acids when burned. This is mandated in projects like metro rail, airports, hospitals, and data centres where toxic gas emission must be near zero.
4.6 FRLS Control & Instrumentation Cable
Multi-core shielded cables used in industrial automation, PLC panels, and process control. The FRLS variant ensures fire incidents do not cascade through control cable trays in refineries, power plants, or chemical plants.
5. FRLS Cable Specifications and Sizes
When specifying or procuring FRLS cable, the following technical parameters matter:
| Parameter | Specification |
|---|---|
| Conductor Material | Electrolytic Grade Copper (EC Grade) or Aluminium |
| Insulation | FRLS PVC Compound / XLPE |
| Outer Sheath | FRLS PVC / LSZH Compound |
| Conductor Sizes | 0.5 sq mm to 400 sq mm (as per IS 694 / IS 7098) |
| Voltage Grade | 1100V (LT), 3.5 kV, 6.35/11 kV, 19/33 kV (HT) |
| Max. Operating Temp (PVC) | 70°C continuous, 160°C short circuit |
| Max. Operating Temp (XLPE) | 90°C continuous, 250°C short circuit |
| Smoke Density (IEC 61034) | Minimum 60% light transmittance |
| Flame Test | IEC 60332-1 (single cable), IEC 60332-3 (bunched) |
| HCl Gas Emission | <15% (FRLS PVC), 0% (LSZH) |
| Colour Codes | Red, Yellow, Blue, Black, Green-Yellow (Earth) |
| Standard Drum Length | 100m, 200m, 500m, 1000m coils/drums |
Common FRLS Cable Sizes and Current Ratings
| Size (sq mm) | Current Rating (A) Copper | Typical Application |
|---|---|---|
| 1.0 sq mm | ~13 A | Light points, fans |
| 1.5 sq mm | ~16 A | Power sockets, lighting circuits |
| 2.5 sq mm | ~23 A | Air conditioners, general power |
| 4.0 sq mm | ~30 A | Sub-distribution boards |
| 6.0 sq mm | ~38 A | Large appliances, submain wiring |
| 10 sq mm | ~52 A | Main feeder lines |
| 16–25 sq mm | ~68–90 A | Panel to distribution board feeders |
| 35–95 sq mm | ~110–185 A | Industrial feeders, main risers |
| 120–400 sq mm | ~220–400 A | HT/LT main incomer cables |
6. IS Standards and IEC Compliance for FRLS Cable
Sourcing FRLS cables from ISI-marked, BIS-certified manufacturers is essential for project approvals, fire NOC, and quality assurance. Here are the key standards:
Indian Standards (BIS)
-
IS 694:2010
PVC insulated cables for working voltages up to and including 1100 V (covers FRLS PVC house wires and flexible cables) -
IS 7098 Part 1:1988
XLPE insulated cables for working voltages up to and including 1100 V -
IS 7098 Part 2:1985
XLPE insulated cables for working voltages 3.5 kV up to and including 33 kV
International Standards (IEC)
- IEC 60332-1 Test for flame propagation on a single cable
- IEC 60332-3 Test for flame propagation on bunched cables (vertical tray test)
- IEC 61034-2 Measurement of smoke density of cables burning under defined conditions
- IEC 60754-1 & 2 Test on gases evolved during combustion of materials from cables (HCl content)
- IEC 62821 (EN 50575) European CPR (Construction Products Regulation) classification for cables in buildings
Pro tip for bulk buyers: Always ask for the manufacturer's BIS licence number, ISI mark certificate, and IEC test reports before finalising a bulk order. Reputable suppliers provide these transparently.
7. Where Are FRLS Cables Used? Applications & Sectors
FRLS cables are the go-to wiring solution wherever fire safety regulations are strict. Here is a sector-wise breakdown:
7.1 High-Rise Residential Buildings
Under the NBC 2016 and local municipal fire codes, all buildings above 15 metres must use FRLS cables for internal wiring. Builders and real estate developers procure FRLS house wires in bulk for entire townships and housing complexes.
7.2 Commercial Complexes and Shopping Malls
High footfall areas with complex wiring layouts require FRLS cables to limit fire propagation through cable trays and ensure safe evacuation.
7.3 Hospitals and Healthcare Facilities
Patients in ICUs and OTs cannot be moved quickly. FRLS (ideally LSZH) cables ensure that even in a fire, toxic smoke is minimal and life support systems remain operational longer.
7.4 Hotels and Hospitality
Star-category hotels must comply with fire safety norms. FRLS cabling is specified in all internal wiring, cable trays, and electrical rooms.
7.5 IT Parks, Data Centres, and BPO Campuses
Dense cable routing in server rooms and data halls demands LSZH or FRLS cables to prevent fire and smoke damage to expensive equipment and sensitive data.
7.6 Metro Rail, Airports, and Mass Transit
Underground metro stations, airport terminals, and railway tunnels mandate ZHFR/LSZH cables to ensure passenger safety and comply with international transport safety norms.
7.7 Industrial Plants and Power Stations
Refineries, chemical plants, and thermal power stations use FRLS armoured cables in cable trays and underground trenches to prevent fire cascading through electrical systems.
7.8 Educational Institutions and Government Buildings
Schools, colleges, and public sector offices increasingly specify FRLS cables in their civil projects to meet CPWD and PWD guidelines.
8. Benefits of Using FRLS Cable in Your Project
- Life Safety: Reduces smoke inhalation risk during fire, giving occupants more time to evacuate.
- Fire NOC Compliance: Mandatory for obtaining fire NOC from local fire departments for high-rise and public buildings.
- NBC 2016 Compliance: Meets India's National Building Code requirements for electrical safety.
- Lower Fire Risk: Self-extinguishing property prevents fire from spreading through cable trays.
- Long-Term Cost Savings: Prevents total wiring loss in a fire event; insurance premiums may be lower.
- International Project Eligibility: Meets IEC and European (CPR) standards for export-oriented and multinational projects.
- Reduced Liability: Contractors using specified FRLS cables face lower legal liability in fire incidents.
- Environmental: LSZH variants eliminate halogen acids, protecting both people and the environment.
9. Top FRLS Cable Brands in India
India has several well-established manufacturers producing ISI-certified FRLS cables. When procuring in bulk, compare quality certifications, delivery timelines, technical support, and pricing:
- Polycab India Ltd India's largest cable manufacturer; extensive FRLS range
- Havells India Ltd Strong brand presence; FRLS house wires popular in residential projects
- Finolex Cables Ltd Reputed for FRLS flexible cables and house wires
- KEI Industries Ltd Specialises in FRLS XLPE and HT cables for industrial projects
- RR Kabel Competitive pricing; good coverage for FRLS building wires
- Sterlite Technologies Focus on fibre and speciality FRLS cables
- Lapp India (ÖLFLEX) Premium FRLS control and industrial cables
- Universal Cables Ltd FRLS power and control cables for infrastructure projects
For government and CPWD projects, always verify BIS certification and ask for copies of valid IS licence certificates from the manufacturer.
10. How to Buy FRLS Cable in Bulk Complete Procurement Guide
If you are a contractor, builder, developer, or project procurement manager looking to source FRLS cables in large quantities, follow this structured approach to get the best value without compromising on quality:
Step 1: Prepare a Cable Schedule
Before approaching suppliers, prepare a cable schedule a detailed list of cable types, sizes, voltage grades, drum lengths, and estimated quantities (in metres or km). This allows accurate quotation comparison.
Step 2: Specify the Correct Standard
Clearly mention in your RFQ: IS 694 / IS 7098, FRLS grade, conductor material (copper or aluminium), insulation type (PVC or XLPE), and any special requirements (armoured, LSZH, UV-resistant, etc.).
Step 3: Verify Manufacturer Credentials
- BIS ISI mark licence number
- IEC test reports (IEC 60332, IEC 61034, IEC 60754)
- Factory audit reports (if required)
- Reference projects and list of clients
Step 4: Request Samples and Test Reports
For bulk orders above ₹10 lakhs or 10,000 metres, always request samples and independently verify them at a NABL-accredited testing lab. Key tests: conductor resistance, insulation resistance, flame test, smoke density.
Step 5: Negotiate Commercial Terms
Key commercial terms for bulk FRLS cable orders:
- Price per metre or per kg (confirm if GST inclusive or exclusive)
- Drum sizes and packaging
- Delivery schedule and lead time (typically 2–6 weeks for large orders)
- Advance payment terms (typically 30–50% for manufacturers)
- Warranty (standard 1 year; premium brands offer 10-year product warranty)
- Return and replacement policy for defective drums
Step 6: Compare Total Cost of Ownership
Do not just compare the per-metre price. Factor in: conductor purity (EC grade vs standard), insulation thickness, drum fill factor, and freight costs. A cheaper cable with thinner insulation may fail tests or require early replacement.
Step 7: Place Order with Clear PO Terms
Include in your purchase order: cable specification, IS standard reference, drum markings required, test certificate requirements, delivery milestones, and penalty clauses for delay or quality failure.
11. FRLS Cable Price Guide (2026)
FRLS cable prices depend on copper/aluminium commodity prices, conductor size, insulation type, and brand. The following is an indicative price range for copper conductor FRLS PVC cables for bulk procurement in India as of early 2026:
| Size (sq mm) | Type | Approx. Price Range (₹/metre) |
|---|---|---|
| 1.0 sq mm | Single core FRLS PVC house wire | ₹12 – ₹18 |
| 1.5 sq mm | Single core FRLS PVC house wire | ₹16 – ₹24 |
| 2.5 sq mm | Single core FRLS PVC house wire | ₹26 – ₹38 |
| 4.0 sq mm | Single core FRLS PVC | ₹40 – ₹58 |
| 6.0 sq mm | Single core FRLS PVC | ₹58 – ₹82 |
| 10 sq mm | Single core FRLS PVC | ₹90 – ₹130 |
| 2.5 sq mm × 3C | 3-core FRLS PVC | ₹75 – ₹110 |
| 16 sq mm × 4C | 4-core FRLS XLPE unarmoured | ₹380 – ₹520 |
| 25 sq mm × 4C | 4-core FRLS XLPE armoured | ₹580 – ₹780 |
| 50 sq mm × 3.5C | 3.5-core FRLS XLPE armoured | ₹950 – ₹1,350 |
| 95 sq mm × 3.5C | 3.5-core FRLS XLPE armoured | ₹1,800 – ₹2,600 |
Note: Prices are indicative and subject to copper LME price fluctuations. Bulk buyers (100+ km or ₹50L+ orders) typically negotiate 8–15% lower than list price. Always get a formal quotation from the manufacturer or authorised distributor.
12. Frequently Asked Questions About FRLS Cable
What is FRLS cable full form?
FRLS full form is Flame Retardant Low Smoke. FRLS cables are designed to resist fire propagation and emit minimal toxic smoke when exposed to high heat or flames.
What is the difference between FR and FRLS cable?
FR (Flame Retardant) cables resist fire but may emit thick, toxic smoke. FRLS (Flame Retardant Low Smoke) cables also limit smoke density and toxic gas emission, making them safer for enclosed and crowded spaces.
Is FRLS cable mandatory in India?
Yes. Under the National Building Code (NBC) 2016 and local fire safety regulations, FRLS cables are mandatory for all high-rise buildings (above 15m), hospitals, hotels, educational institutions, and public infrastructure. Fire departments require proof of FRLS cabling for fire NOC issuance.
Where are FRLS cables used?
FRLS cables are widely used in residential high-rises, commercial complexes, hospitals, hotels, airports, metro rail, IT parks, data centres, and industrial plants where fire safety compliance is mandatory.
What IS standard applies to FRLS cables in India?
FRLS cables in India are governed by IS 694 for PVC insulated cables and IS 7098 for XLPE cables. Flame retardant and low smoke properties are tested per IEC 60332 and IEC 61034.
Can FRLS cables be used outdoors?
FRLS cables are primarily designed for indoor use. For outdoor or underground applications, use armoured FRLS cables with UV-resistant or PE outer sheath variants.
What is the difference between FRLS and LSZH (ZHFR) cable?
FRLS cables use modified PVC compounds that limit smoke but may still release some halogen acids. LSZH (Low Smoke Zero Halogen) or ZHFR cables use halogen-free compounds and emit zero halogen acids the highest safety grade, specified for metro rail, hospitals, and airports.
What is the minimum order quantity for bulk FRLS cable supply?
Most manufacturers consider orders above 500 metres (single item) or ₹5 lakhs as bulk. For project-level procurement above 50 km or ₹50 lakhs, direct factory supply with volume discounts is possible.
How do I verify the quality of FRLS cable before bulk purchase?
Ask for BIS ISI certificate, IEC test reports (IEC 60332, IEC 61034, IEC 60754), and conduct independent third-party testing at a NABL-accredited laboratory. Always check conductor weight (kg/km) to verify actual copper content.
Which is better FRLS copper or FRLS aluminium cable?
Copper FRLS cables offer higher conductivity, smaller cross-section, and longer life preferred for critical applications. Aluminium FRLS cables are 50–60% lighter and cheaper, suitable for large-section feeder cables (35 sq mm and above) where weight and cost savings are significant.
13. Conclusion Why FRLS Cable Is a Non-Negotiable in Modern Construction
Whether you are building a 30-storey residential tower, setting up a 500-bed hospital, or managing the electrical procurement for a metro rail project FRLS cable is not a choice, it is a requirement. It saves lives, ensures regulatory compliance, protects your investment, and reduces long-term liability.
The extra cost (typically 10–20% over standard FR cables) is negligible compared to the safety value it delivers. And with smart bulk procurement strategies clear specifications, verified manufacturers, direct factory sourcing, and volume negotiation you can keep project costs competitive without compromising on safety.
Key takeaways:
- FRLS = Flame Retardant Low Smoke the minimum safety specification for modern buildings
- Always insist on BIS-certified, ISI-marked FRLS cables with valid IEC test reports
- Use LSZH/ZHFR for hospitals, metro, airports, and data centres
- Prepare a proper cable schedule before bulk procurement to get accurate pricing
- Verify copper content and conductor quality not just the label
Frequently Asked Questions (FAQ)
Looking to source FRLS cables for your project? Contact us for a bulk quotation, technical consultation, and sample testing support. Our team specialises in large-scale cable supply for builders, contractors, and EPC companies across India.
