Table of Contents
- In the field of instrumentation, adherence to standards like IS: 8130, ANSI MC 96.1, and IEEE 383 is essential.
- These standards outline vital tests ensuring the reliability and safety of cables and conductors, covering aspects such as flexibility and fire resistance.
Standards for the Testing of Instrumentation Cables
IS : 8130:
- Annealing test for conductors: This test assesses the softness and flexibility of conductors by subjecting them to a controlled heating and cooling process.
- Wrapping test for conductors: This test evaluates the ability of conductors to withstand wrapping and unwrapping without damage.
- Persulphate test for tinned copper conductors: It determines the presence of any surface impurities on tinned copper conductors using persulphate solution.
- Conductor resistance test for copper conductors: This test measures the electrical resistance of copper conductors.
ANSI MC 96.1:
- Thermo-emf performance test for thermocouple cables: Evaluates the performance of thermocouple cables by measuring the thermal-electromotive force (EMF) under various conditions.
- Loop resistance test for thermocouple cables: Determines the resistance of the loop formed by the thermocouple cables.
IS : 5831:
- Insulation and sheath thickness test: Measures the thickness of insulation and sheath layers.
- Tensile strength of insulation and sheath: Determines the maximum tensile load a material can withstand before breaking.
- Elongation test for insulation and sheath: Measures the percentage increase in length of a material under tension.
- Shrinkage test for insulation and sheath: Determines the shrinkage properties of insulation and sheath materials.
- Loss of mass test for insulation and sheath: Measures the mass loss of insulation and sheath materials under specified conditions.
- Aging test for insulation and sheath: Evaluates the resistance of insulation and sheath materials to aging.
- Heat shock test for insulation and sheath: Determines the ability of insulation and sheath materials to withstand sudden changes in temperature.
- Bleaching and blooming test for insulation and sheath: Evaluates the discoloration and blooming characteristics of insulation and sheath materials.
- Insulation resistance test for insulation and sheath: Measures the resistance to the passage of electric current through insulation and sheath materials.
- Flammability test for cable: Determines the flammability characteristics of cables.
IS : 3975:
- Tensile strength of armor material: Measures the maximum tensile load a material can withstand before breaking.
- Elongation test for armor material: Measures the percentage increase in length of a material under tension.
- Zinc coating test on GI armor wire: Evaluates the thickness and adherence of zinc coating on galvanized iron (GI) armor wire.
IS : 1554:
- Tensile strength for insulation and sheath: Measures the maximum tensile load insulation and sheath materials can withstand before breaking.
- Elongation strength for insulation and sheath: Measures the percentage increase in length of insulation and sheath materials under tension.
- High voltage test for insulation and sheath: Evaluates the electrical insulation properties of insulation and sheath materials under high voltage conditions.
IS : 694:
- Spark test for insulation and sheath: Determines the resistance of insulation and sheath materials to electrical sparks.
- HV test for insulation and sheath: Evaluates the electrical insulation properties of insulation and sheath materials under high voltage conditions.
IEEE : 383:
- Flame resistance test: Determines the ability of materials to resist flame propagation.
ASTM-D-2863:
- Limiting Oxygen Index test: determines the lowest possible oxygen concentration necessary for enabling a material’s combustion.
- Temperature Index Test ASTM -D -2843 Smoke density test: Determines the smoke density characteristics of materials under specified conditions.
IEC -332- 1 and 3:
- Flammability test: Evaluates the flammability characteristics of materials.
IEC -754-1:
- HCI gas emission test: Measures the emission of hydrogen chloride gas from materials under specified conditions.
SS-424-14-75 (F-3 ):
- Flame retardancy test (Swedish chimney test): Determines the flame retardancy properties of materials using the Swedish chimney test method.
- Noise rejection ratio test: This test evaluates the ability of a cable or conductor to reject external noise interference.
- Rodent & termite resistance chemical test: Determines the resistance of materials to damage caused by rodents and termites, often through the application of specific chemical treatments.
Additional Considerations for Instrumentation Cable Testing
Instrumentation cable testing considers environmental, shielding, flexibility, chemical resistance, marking, EMC, and life cycle aspects for optimal performance.
Environmental Resistance:
- Standards may include evaluations for resistance to extreme temperatures, moisture, chemicals, and UV exposure.
Shielding Effectiveness:
- Testing ensures shielding effectiveness, crucial for minimizing electromagnetic and radio frequency interference, safeguarding signal integrity.
Cable Flexibility:
- Evaluations of cable flexibility guarantee durability under repeated bending or movement, essential for applications with dynamic requirements.
Chemical Resistance:
- Tests evaluate cable materials’ resistance to chemicals, oils, solvents, and corrosive substances.
Cable Marking and Identification:
- Standards specify requirements for proper labeling, aiding installation, maintenance, and troubleshooting.
Electromagnetic Compatibility (EMC):
- Conformance to EMC standards mitigates electromagnetic emissions and susceptibility, preventing interference with nearby electronic systems.
Life Cycle Testing:
- Life cycle testing assesses long-term durability and reliability, simulating continuous operation to ensure sustained performance over time.
Instrumentation Cable Specifications Sample
This cable specification table outlines the essential components and characteristics of instrumentation cables, crucial for various industrial and communication applications. From conductor types and core insulation materials to sheathing and armor, these specifications ensure reliability and performance in diverse operating environments.
| S. No | Part | Type | Range |
| 1 | Conductor | Solid Conductor | Standard sizes : 0.81mm dia (0.5mm2 ), 20 AWG 1.13mm dia (1.0mm2 ) 1.29mm dia (1.31 mm2 ),16AWG 1.38mm dia. (1.5mm2 ) 1.79mm dia (2.0mm2 ) |
| Stranded Conductor | Standard sizes : 7 x 0.31mm dia. (0.5mm2 ), 20 AWG7 x 0.43mm dia. (1.0mm2 ) 7 x 0.49mm dia (1.3mm2 ) 7 x 0.53mm dia (1.5mm2 ) 7 x 0.67mm dia. (2.5mm2 ) | ||
| 2 | Core Insulation | PVC 700C PVC 850CPVC 1050C LDPE | Standard thickness : 0.6mm |
| 3 | Units | Core Pair TriadQuad | Length of Twist ; Pair 0.5mm2 conductor 55 mm/18 twists per meter 0.1mm2 conductor 60 mm/17 twists per meter 16 AWG conductor 60 mm/17 twists per meter 1.5mm2 conductor 70 mm/14 twists per meter 2.5mm2 conductor 80 mm/12 twists per meter |
| 4 | Unit screen | 1 layer of polyester tape. 1 tinned copper drain wire. 1 layer of aluminum mylar with 25% overlap thick. For 100% coverage. 1 layer of Polyester tape. | Polyester tape 25 micron thick 7 x 0.31mm dia. (0.5mm2 ) Aluminum – mylar Tape 65 micron thick. Polyester tape 25 micron thick. |
| 5 | Number of units | Single unit Multi unit | |
| 6 | Communication pair | 7 x 0.31 mm dai. (0.5 mm2) insulated, twisted pair | Provided for cables with 6 pairs, 6 traids, 6 quads and above. |
| 7 | Overall Screen | Same as for Unit Screen (4.) | |
| 8 | Inner Sheath | PVC 700C PVC 850C PVC 1050C FRLS Grade PVC | Standard thickness : 1.0 mm min. |
| 9 | Armour | Galvanized roundsteel wires | Standard size 1.0 mm dia. for cable OD up to 1.3 mm and 1.4 mm dia. above 13 mm |
| Galvanized flat Steel wires | 4 x 0.81 mm (Optional) | ||
| 10 | Outer Sheath | PVC 700CPVC 850CPVC 1050CFRLS Grade PVC | Standard thickness : 1.2 mm for Cable OD up to 13 mm and 1.50 mm above 13 mm |
Types of Instrumentation Cables
Instrumentation cables are vital for signal transmission, power supply, and temperature measurement in various industries. Common types include signal, control, power, thermocouple, and RTD cables, each serving specific functions.
Signal Cables:
- Transmit low-voltage signals reliably over short to medium distances.
- Commonly used in industrial automation, process control, and telecommunications.
Control Cables:
- Transmit control signals to operate electrical equipment and machinery.
- Often multi-conductor with shielding, used in industrial and building automation.
Instrumentation Power Cables:
- Supply power to instrumentation and control devices.
- Higher voltage and current ratings, essential for various industrial applications.
Thermocouple Extension and Compensating Cables:
- Connect thermocouples to temperature measurement systems.
- Minimize temperature-induced errors for accurate temperature measurement.
RTD (Resistance Temperature Detector) Cables:
- Connect RTD sensors to measurement instruments.
- Ensure accurate temperature sensing in HVAC, automotive, and aerospace applications.
Load Cell Cables:
- Load Cell cables connect load cells to measurement devices, facilitating accurate weight or force measurement.
- They ensure reliable signal transmission in applications such as industrial weighing systems and force testing equipment.
Fiber Optic Cables:
- Transmit data using light pulses, immune to electromagnetic interference, suitable for high-speed communication over long distances.
Reference: General Instruments
