Instrumentation cables are a very important part of any process plant. in this post, I will give you information on the Standards and Specifications of Instrumentation Cables.
Instrumentation cables look like a simple thing but for selecting some many standards and specifications need to be followed.
Introduction
Instrument cables are responsible for carrying transmitter signals from field to control panel and command signals from the control panel to field.
The selection of proper instrument cables is a very important task for instrumentation engineers.
Many specifications and standards will need to be followed while selecting instrumentation cables.
Types of Cables used in Industry
- Fire Resistant Cables
- Fire Retardant Cables
- Signal Cables
- Single pair/triad shielded cable
- A. Multi-pair/ Multi-triad Cable with individual pair shield and overall shield
- B. Multi-pair/ Multi-triad Cable with only shield
- C. Multi-pair/ Multi-triad Cable with individual pair shield and overall shield
- Multi-pair/multi-triad cable with an overall shield only
- Single or Two pair thermocouple extension Cable
- Multi-pair thermocouple extension cable
- Power supply cable
Instrumentation Cable Standards
Instrumentation cables look like a simple thing but for selecting instrumentation many standards will follow.
| No. | Standard | Description |
|---|---|---|
| 1 | IEC 332-3 Part 3 | Tests on bunched wires and cables. |
| 2 | ASTM D 2863 | Oxygen Index |
| 3 | BS 5308 Part 2 | Specification for PVC insulated cables. |
| 4 | DIN 50049 | Document material testing. |
| 5 | IEC 60331 and IEC 60332-3 | Resistant Cables |
| 6 | IEC 60332-3 | |
| 7 | ISA/ANSI MC96.1 | |
| 8 | ISA/ ANSI MC96 | |
| 9 | IEC:502 | Mechanical Test |
| 10 | NEMA-WC-5 | Accelerated Water absorption test |
| 11 | ASTM D 2863 | Oxygen Index Temperature index |
| 12 | IEC 754-1 | Acid gas generation |
| 13 | SS-424 14 75 (Class F3) IEEE 383 | Flammability |
| 14 | ASTM D 2843 | Smoke Generation |
| 15 | API-550 Part –I SECTION VII | Physical separation of power and signal cables |
| 16 | IS:3975 and IS:2633 | Armour material and uniformity of galvanization |
Specification of Instrumentation Cables
These are all the Instrumentation Cables specifications that our vendor will include in the Specification sheet.
These are all specifications that need to be considered before selecting the right instrumentation cables for any industry.
and Specifications may change according to industry requirements.
- Conductor size
- Type of cable
- Insulation material, thickness, temperature, and voltage withstanding rating.
- Number of Twists per unit length, nos. of pairs
- Inner jacket material, thickness, temperature, and voltage rating.
- Outer jacket material, thickness, temperature, and voltage rating.
- Overall Outside Diameter
- Over Armour diameter.
- Under Armour diameter.
- Capacitance (between adjacent cores)
- Inductance
- L/R ratio.
- Minimum bending radius.
- Insulation resistance
- Resistance per km
- Results of cold bending test, hot aging test, breakdown load elongation, tensile
- stress etc.
- Minimum drum length possible.
- O.D. tolerance
- Basic Standards were followed.
- Net weight in Kg / Km
Inspection and Testing for Instrumentation Cables
Inspection and Testing are very important to ensure that Instrumentation cables follow international standards and rules for safety.
There are different types of Inspections and Tests performed on Instrumentation Cable Here is the List.
| No. | Test and Inspections |
|---|---|
| 1 | Flame retardant |
| 2 | Armour test |
| 3 | Conductor resistance per Km |
| 4 | Cable capacitance, L/R ratio. |
| 5 | Insulation resistance, Voltage test |
| 6 | Electrostatic noise rejection test |
| 7 | Tests for uniformity of galvanization |
| 8 | Oxygen index test |
| 9 | Bending Test |
| 10 | Mechanical Test |
| 11 | Temperature Index |
| 12 | Flammability |
| 13 | Acid gas generation |
| 14 | Smoke Generation |
EndNote: –
I hope you get new information and knowledge from this article and now you can realize that selection of a Proper Instrumentation cable is a very tough task for engineers.
If you like this you may also like my other previous post.
