Quality & Testing · IS 694:2010 · IEC Standards · ISO 9001:2015

Testing is not the last step.
It runs through every step.

National Cables operates a fully equipped in-house testing laboratory covering electrical, mechanical, thermal, and fire performance. Every production lot is tested before dispatch. Routine test results and BIS compliance documentation are issued for all institutional and export orders.

100%
Lots tested before dispatch
ISO
9001:2015 certified
BIS
IS 694:2010 licence held
IEC
International test protocols
Testing Infrastructure

Four categories. Every cable. Every lot.

Our testing laboratory covers the full range of verification required by IS 694:2010, IS 17048:2018, and the IEC standards they reference. Testing is divided into four functional categories — electrical, fire and flammability, mechanical and thermal, and calibration and measurement.

Electrical Testing
Verification of conductor resistance, insulation resistance, and high-voltage withstand — the three core electrical parameters specified in IS 694:2010 and IS 8130:2013.
AC High Voltage Test System — insulation withstand per IS 694:2010
High Voltage DC Test System (kV / mA rated) — dielectric integrity under DC
Precision Double Kelvin Bridge — conductor resistance to IEC 60228
Digital Precision Ohmmeter — low-resistance measurement
Advanced Megohmmeter (500 V / 1000 V) — insulation resistance per IS 694:2010 (500 V minimum; 1000 V DC for margin on 1100 V-rated cable)
Calibrated Standard Resistance Boxes — reference calibration
Fire & Flammability Testing
Oxygen index, temperature index, smoke density, halogen acid gas, and flame propagation — the full suite required for FR, FR-LSH, and IS 17048:2018 HFFR classification.
Oxygen/Temperature Index Analyser — IS 10810 (Part 58):1998 & IS 10810 (Part 64):2003
Halogen Acid Gas Emission Analyser — IS 10810 (Part 59):1988 / IEC 60754-1
Smoke Density Measurement System — IS 13360 / IEC 61034-2
Flame Propagation Chamber — IEC 60332-1-2:2004 and IEC 60332-3-24:2018
Thermal, Mechanical & Material Testing
Long-term thermal stability, mechanical strength, flexibility at low temperature, and compound quality — the parameters that determine whether a cable performs over its full service life.
Digital Thermal Aging Oven (to 200°C) — accelerated aging per IS 694:2010
Automated Tensile Testing System (5000 N) — tensile strength and elongation
Automated Cold Impact Tester — brittleness at low temperature
Cold Bend Test Apparatus — flexibility verification at −20°C
Environmental Conditioning Chamber (−20°C) — cold performance simulation
Water Immersion Setup — submersible cable insulation resistance
Melt Flow Index Tester — compound processability verification
Calibration & Precision Measurement
Reference instruments and dimensional measurement tools — ensuring that all testing equipment produces results traceable to national and international measurement standards.
Travelling Microscope — dimensional verification of conductor and insulation
Kelvin Bridge — low-resistance calibration reference
Standard Resistance Box — MΩ meter calibration
Digital Ohmmeter (0.1 MΩ – 1000 MΩ) — wide-range insulation measurement
Heat Shock Mandrel Set — insulation crack resistance
Dumbbell Cutting Press — standard specimen preparation for tensile tests
Fire Performance Testing — FR, FR-LSH, and IS 17048:2018 HFFR
What each fire test actually measures — and what the limits are.
IEC 60332-1-2:2004
Vertical Flame Propagation
A single cable is mounted vertically and exposed to a defined flame for 60 seconds. The test measures how far the char extends above the flame zone.
Limit: char must not exceed 540mm above the burner
IEC 60332-3-24:2018
Bunched Cable Flame Spread
Multiple cables installed in a cable tray at defined fill density. Tests whether flame spreads vertically when cables are installed as a group — the real installation scenario.
Category C: 1.5 L/m cable — 2.5m flame limit
IS 10810 (Part 58):1998 / ASTM D2863
Oxygen Index
Measures the minimum oxygen concentration required to sustain combustion. Higher OI = harder to burn. Standard PVC: ~25–27%. FR-LSH: >29%. IS 17048:2018 HFFR: >30%.
FR-LSH: OI >29% · HFFR: OI >30%
IEC 60754-1
Halogen Acid Gas
Cable sample burned in a furnace tube. Combustion gases absorbed and measured for HCl and other halogen acid content. FR-LSH limits halogen; HFFR eliminates it.
FR-LSH: HCl <15% · HFFR: HCl <0.5%
IEC 61034-2
Smoke Density
Cables burned in a 3m × 3m × 3m test chamber. Light transmittance measured. Low transmittance = dense smoke = reduced visibility for evacuation and firefighting.
IS 17048:2018 HFFR: transmittance ≥70%
IS 10810 (Part 64):2003
Temperature Index
Per IS 10810 (Part 64):2003, the Temperature Index is the temperature at which the material's Oxygen Index equals 21% — i.e. the OI has fallen to the same oxygen level as ambient air, not merely “tested in air.” FR-LSH requires TI >250°C.
FR-LSH: TI >250°C
Test Protocols

Routine testing on every lot. Type testing for long-term validation.

Routine Tests
Every production lot, before dispatch
Routine tests verify that the finished cable meets specification. They are conducted on every drum before it leaves the facility — not on a sample from the batch.
Conductor resistance — IS 8130:2013 / IEC 60228 limits
Insulation resistance — per IS 694:2010
AC high voltage withstand — IS 694:2010 test voltage
Insulation and sheath thickness measurement
Overall diameter measurement
Spark test (continuous — during extrusion)
Conductor resistance confirmation at final coil
Type Tests
Long-term performance validation
Type tests validate the design and materials of a cable construction — they confirm performance under conditions that routine production testing cannot simulate in real time.
Thermal aging — mechanical properties after 7 days at 100°C
Cold bend — flexibility at −15°C to −20°C
Cold impact — impact resistance at low temperature
Flame propagation — IEC 60332-1-2:2004
Oxygen index — IS 10810 (Part 58):1998
Halogen content — IEC 60754-1
Smoke density — IEC 61034-2 (for HFFR/FR-LSH)
Water absorption — long-term insulation stability
Compliance Standards

Current active standards — not superseded editions.

All testing is conducted to current active editions of Indian and international standards. Where IS standards reference IEC equivalents, both are applied.

IS 694:2010
PVC insulated cables up to 1100V — with Amendments 1–4 (current to 2023)
Primary standard for FR, FR-LSH, multicore, submersible, and flexible cable
IS 17048:2018
Halogen-free flame-retardant cables up to 1100V
HFFR/LSZH cable range — separate and more demanding than IS 694:2010
IS 8130:2013
Conductors for insulated electric cables
Class 1, 2, 5 conductor requirements — resistance limits per cross-section
IS 5831:1984
PVC insulation and sheath of electric cables
Compound specifications — Type D (70 °C PVC per IS 694:2010 / IS 5831:1984), ST1, ST2; Types B, C where applicable
IEC 60228:2004
Conductors of insulated cables
International equivalent to IS 8130:2013 — applied in parallel for export orders
IEC 60332-1-2:2004
Vertical flame propagation — single cable
Applicable to all FR and FR-LSH cables — standard test for CE marking
IEC 60332-3-24:2018
Flame spread — bunched cables, Category C
FR-LSH and IS 17048:2018 HFFR — installation-realistic test for grouped cables
IEC 60754-1
Halogen acid gas generation test
FR-LSH: HCl <15% · HFFR (IS 17048:2018): HCl <0.5%
IEC 61034-2
Smoke density — light transmittance test
IS 17048:2018 HFFR requires transmittance ≥70% in 3m × 3m × 3m chamber
Frequently Asked Questions

Quality & testing — common questions.

What the in-house laboratory covers and how routine and type tests are conducted on National Cables production.

What categories of testing does the in-house laboratory cover?

The laboratory is organised into four functional categories:

  • Electrical — conductor resistance (Precision Double Kelvin Bridges), insulation resistance (Advanced Megohmmeters at 500 V / 1000 V), AC and DC high-voltage withstand
  • Fire & Flammability — oxygen index, temperature index, smoke density, halogen acid gas, and flame propagation per IS 10810, IEC 60332, IEC 60754, IEC 61034
  • Thermal, Mechanical & Material — accelerated aging to 200°C, tensile strength (5000 N capacity), cold impact and bend at −20°C, water immersion for submersibles, melt flow index
  • Calibration & Precision — travelling microscopes, Kelvin bridges, calibrated standard resistance boxes
What is the difference between routine tests and type tests?

Routine tests are performed on every production lot before dispatch — not on a sample, but on every drum. They cover conductor resistance, insulation resistance, AC high-voltage withstand, thickness and diameter measurements, and the continuous inline spark-test record from extrusion.

Type tests validate cable design and materials under conditions that production testing cannot simulate in real time: thermal aging at elevated temperature, cold bend flexibility, vertical flame propagation per IEC 60332-1-2:2004, oxygen index per IS 10810 (Part 58):1998, halogen acid gas per IEC 60754-1, and smoke density per IEC 61034-2. Type tests are performed less frequently, typically when validating a new cable construction.

What fire-performance limits apply to FR-LSH and HFFR cables?

For FR-LSH cables (IS 694:2010 FR-LSH category):

  • Oxygen Index > 29%
  • Temperature Index > 250°C per IS 10810 (Part 64):2003
  • HCl emission < 15% per IEC 60754-1

For HFFR cables (IS 17048:2018):

  • Oxygen Index > 30%
  • HCl emission < 0.5% per IEC 60754-1
  • Smoke transmittance ≥ 70% in 3m × 3m × 3m chamber per IEC 61034-2

Both pass vertical flame propagation per IEC 60332-1-2 (char limit 540 mm above burner) and bunched cable flame spread per IEC 60332-3-24:2018 Category C (1.5 L/m fuel limit).

How is thermal aging performed, and what does it confirm?

Thermal aging is conducted in a digital thermal conditioning oven up to 200°C. Test samples are exposed to accelerated aging conditions to simulate long-term in-service degradation. After conditioning, mechanical properties — tensile strength and elongation — are re-measured to confirm the insulation and sheath retain adequate strength and flexibility after the equivalent of years of service at elevated temperature.

Cold bend testing at −15°C to −20°C verifies the cable remains flexible at low temperature; cold impact testing confirms the sheath does not fracture under mechanical stress in freezing conditions. For submersible cables, water immersion testing measures insulation resistance after long-term immersion to confirm the insulation barrier remains effective under continuous water exposure.

Request test certificates or compliance documentation.

Routine test results, BIS licence reference, and type test records are issued for institutional procurement and export orders.