What is BS5308?
BS5308 is a British Standard defining low-voltage instrumentation cables used for transmitting analogue and digital signals in industrial environments. It's the common shorthand for robust, screened instrumentation cables with well-defined construction and performance for process control, monitoring, and safety systems.
These instrumentation cables are multi-pair or multi-triad, screened, and designed to minimise noise, cross-talk, and signal loss over long runs.
How PAS5308 Relates to BS5308
PAS 5308 is a BSI Publicly Available Specification that updates and carries forward the specification framework of BS 5308 for instrumentation cable. In procurement terms, PAS 5308 gives you a clear, standard-based reference for the cable's construction, screening approach, insulation type, and testing requirements, so you can compare like-for-like across suppliers using the same specification basis.
PAS 5308 covers both Polyethylene (PE) and Polyvinyl Chloride (PVC) insulated variants, along with options for individual (IS) or collective (OS) screens and Steel Wire Armour (SWA) for protection.
BS5308 Part 1 vs Part 2
Part 1 PE-Insulated Cable
BS/PAS 5308 Part 1 specifies polyethylene (PE) insulated instrumentation cables. PE insulation delivers lower dielectric losses and reduced capacitance compared with PVC, which helps preserve signal quality, especially for long cable runs and high-accuracy analogue measurements.
As a result, Part 1 PE-insulated constructions are often selected for demanding process control duties in electrically noisy environments, including high-spec oil, gas and petrochemical installations.
Part 2 PVC-Insulated Cable
In contrast, PVC insulation is covered under BS 5308 Part 2, where the focus is usually on general-purpose instrumentation and control applications that prioritise cost and practical installation over maximum electrical performance.
PVC insulation offers good mechanical robustness, flexibility and ease of termination at a competitive cost.
When Each Part is Specified
Engineers typically choose Part 1 when they need superior electrical performance, lower capacitance and stable characteristics over distance or temperature. Part 2 is often specified where cost, flexibility and general utility matter more than marginal electrical gains.
Project specifications may call up Part 1 or Part 2 explicitly by reference to the standard, cable type, and required screening.
BS5308 Type 1, Type 2 and Armour Options
Type 1 Construction
- Conductor: Under 1mm² Class 5 flexible copper conductor; 1mm² and above Class 2 stranded copper conductor.
- Insulation: Part 1 – PE; Part 2 – PVC.
- Screen: Collective aluminium/Mylar tape, or individual and collective screens. Both options come with a 0.5mm² drain wire.
- Outer Sheath: Polyvinyl Chloride (PVC).
- Sheath Colour: Blue or black.
Type 1 Key Features
- Unarmoured construction.
- Relies on tray, duct or conduit for mechanical protection.
- Suitable for low-risk routes inside buildings or protected trenches.
- Reduced diameter and weight can make pulling and termination easier where armour is not essential.
Type 2 Construction
- Conductor: Under 1mm² Class 5 flexible copper conductor; 1mm² and above Class 2 stranded copper conductor.
- Insulation: Part 1 – PE; Part 2 – PVC.
- Screen: Collective aluminium/Mylar tape, or individual and collective screens. Both options come with a 0.5mm² drain wire.
- Bedding: Polyethylene (PE).
- Armour: Galvanised Steel Wire Armour (SWA).
- Outer Sheath: Polyvinyl Chloride (PVC).
- Sheath Colour: Blue or black.
Type 2 Key Features
- Armoured construction employing Steel Wire Armour (SWA).
- High mechanical protection and impact resistance.
- Suitable for outdoor runs, underground installation and exposed areas where accidental damage must be mitigated.
Overall Screen vs Individual Screen – Signal Transmission and EMI Protection
BS5308 instrumentation cables can have an overall screen (OS), or individual and collective screens (IS). An overall screen protects the cable bundle against external EMI (electromagnetic interference).
Individual pair or triad screens limit internal cross-talk between circuits, which is particularly important when mixing low-level analogue, high-speed digital, and noisy on/off signals within the same cable. Choosing the right screen configuration is key to signal integrity and noise control.
Where is BS5308 Instrumentation Cable Used?
Oil, Gas and Petrochemical Plants
- Upstream offshore platforms, drilling rigs and FPSO vessels.
- Midstream pipelines, compressor stations and LNG terminals.
- Downstream refineries, petrochemical plants, gas processing facilities and fuel terminals where reliable signal transmission is essential.
- Process control, safety shutdown systems, fire and gas detection, tank gauging and analyser systems.
- Offshore platforms and refineries where mechanical protection and EMI control are critical.
Water Treatment and Industrial Control
Water and wastewater plants use BS5308 instrumentation cables for:
- Level, flow and pressure transmitters.
- Pump control and dosing systems.
- SCADA links.
- Damp environments, buried ducts and widely distributed assets such as pumping stations.
BMS, Automation and Process Systems
BS5308 instrumentation cables are also used across manufacturing plants, power stations and large commercial buildings.
- Building Management Systems (BMS).
- HVAC control systems.
- Process automation.
- Industrial monitoring and control systems.
Why Choose Cleveland Cable?
- UK's largest stockist of PAS5308 cable.
- High-quality British and European Standard-certified products.
- Competitive prices with fast UK and international delivery.
- Expert technical support for your cable requirements.
- In-house cable testing facilities supporting premium quality control.
Browse cables by standard | Contact Cleveland Cable today for expert advice and bulk pricing on BS5308/PAS5308 instrumentation cable
