Instrumentation Cable BS 5308 Type 1 (24V Pair) — Chemical & Petrochemical Signal Transmission

In a live petrochemical plant, the cost of a corrupted 4-20mA signal isn’t theoretical. It cascades. A false trip, an unplanned shutdown, a batch contaminated because the control system read noise instead of pressure. Most control rooms won’t see the fault until production is already lost. The cable that connects your field instrument to the logic solver is either a reliable data channel or a liability.

This instrumentation cable is built to BS 5308 Part 1 Type 1 standards. It is designed for 24V paired signal transmission in environments where chemical attack and electrical noise co-exist. Our factory maintains this stock specifically for switchgear wiring, process control loops, and DCS/PLC marshalling within refineries and chemical processing facilities. The primary business cases are noise immunity in high-EMI zones and jacket integrity against hydrocarbon-based chemical spillage. This means fewer retransmissions, sustained fire safety ratings, and a lower total lifecycle cost per installed meter.

Why BS 5308 Cable Design Matters in Field Instrumentation

Collective Foil Shield with Tinned Copper Drain Wire

Aluminium/polyester tape applied over each pair and a tinned copper drain wire running the length of the cable. This creates a 100% coverage Faraday cage against the electromagnetic fields generated by variable speed drives and high-voltage power trays running in parallel cable ladders.
Result for your project: You get a clean 4-20mA or HART-compliant signal from the transmitter to the DCS I/O card. This reduces signal conditioning overhead and prevents the controller from deriving false process calculations. No more ghost faults.

Flame-Retardant PVC Compound to IEC 60332-1

The outer jacket is formulated with a specific flame-retardant PVC compound that resists vertical flame propagation on a single wire. In the event of a localized electrical fault inside a crowded marshalling cabinet, the insulation self-extinguishes.
Result for your project: You slow the spread of fire along cable trays. This directly lowers risk in your facility’s incident mitigation strategy. Insurance inspectors and HSE officers reference this exact IEC flame test during audits.

Enhanced Chemical Resistance (Oil & Hydrocarbon)

Standard PVC softens and swells when it comes into prolonged contact with mineral oils, diesel, or aggressive cleaning solvents common in refinery maintenance. Our jacket compound integrates higher molecular weight plasticizers that resist extraction and embrittlement when cables are laid in oily cable trenches or near hydraulic control units.
Result for your project: You won’t need to re-pull entire multi-core runs three years into operations because the jacket has turned brittle and cracked. One less capital expenditure line item during the turnaround window.

Pair Identification via Numbered Cores

Black insulation with durable white ink numbering on each conductor. This engineering choice bypasses the weakness of color-only identification, which fades under constant exposure to high-bay lighting or heat cycling inside uninsulated field junction boxes.
Result for your project: Termination errors drop. Your commissioning crew identifies pairs instantly against the loop drawings without stopping to trace color degradation or relying on banding that can peel off.

Long Continuous Lengths on Heavy-Duty Reels

We supply standard cut lengths on robust wooden drums designed for mechanical pay-off. No mid-span splices that introduce potential impedance anomalies.
Result for your project: You reduce on-site jointing labor and eliminate the weakest point in any instrumentation loop — a hand-spliced tape joint that compromises the shield continuity.

Technical Specifications & Dimensional Data

Industry Applications & Environmental Suitability

• Chemical Processing Plants (Bulk & Fine Chemicals): Wired from field-mounted temperature transmitters and magnetic flowmeters in corrosive bund areas. The jacket resists splash contact with toluene, MIBK, and isopropyl alcohol during routine equipment washdowns.
• Petroleum Refineries (Crude Distillation Units): Used in cable ladders adjacent to heat exchanger banks. The collective foil shield blocks the high-frequency switching noise radiated by adjacent VSD cables, preserving the integrity of the vibration probe signal back to the turbine supervisory system.
• Oil & Gas Storage Terminals: Connects float-level sensors and servo gauges on large bulk storage tanks. The flame-retardant PVC jacket meets the fire safety criteria required within dike containment areas where pooled hydrocarbons could propagate a ground fire.
• Water & Wastewater Treatment: Deployed in sludge dewatering buildings where high humidity and gaseous ammonia have corroded standard communication cables. The solid PVC insulation and tinned drain wire provide a robust barrier against hydrogen sulfide ingress into the conductor bundle.
• Power Generation (Balance of Plant): Installed within the boiler auxiliary panels to link differential pressure transmitters to the burner management system. The numbered pairs enable error-free terminations during high-pressure outage windows when time constraints demand absolute wiring clarity.

International Compliance & Quality Assurance

• ✅ Manufactured to BS 5308 Part 1 Type 1 construction requirements
• ✅ Tested for vertical flame propagation per IEC 60332-1 (Single Cable Fire Test)
• ✅ Conductor dimensions follow IEC 60228 (Class 5 flexible copper)
• ✅ Materials conform to EU RoHS recast (Directive 2011/65/EU) for restricted substances
• ✅ Insulation integrity verified to IEC 60304 (Standard colours for low-frequency cables and wires)
• ✅ Cable drums are tagged with unique batch traceability codes linking back to raw material certificates

Frequently Asked Questions

We normally run 16-pair SWA cables for long outdoor runs. Where does this BS 5308 cable fit into that specification?

BS 5308 Type 1 is an unarmoured cable intended for protected raceways, trunking, or enclosed cable trays. It is not a direct burial or catenary cable. For outdoor runs without conduit, you still need steel wire armoured (SWA) multilayer cables. The engineering choice hinges on shield integrity versus mechanical crush. Use this cable inside a control room, a field junction box, or a conduit system. Use SWA once the tray leaves the pipe rack and heads into the open.

The spec sheet says 300/500V, but our loops only run 24V DC. Is the insulation over-spec’d?

No. The 300/500V rating refers to the dielectric withstand of the insulation, not the operating voltage. This headroom protects your signal during transient voltage surges when a lightning arrestor engages or when an inductive load kicks back onto the common ground. A higher insulation rating reduces the probability of dielectric breakdown and channel-to-channel crosstalk.

Can we order with colored core insulation instead of black with white numbering?

The black-core, white-numbering system is the default for this chemical-resistant grade because it avoids dye degradation issues. However, we do accommodate multicore configurations with standard IEC 60304 colour-coding on a project-specific basis. MOQ thresholds apply. You will need to supply a conductor schedule.

Get a Quick Technical Quotation

Send us your cable schedule and cut-length requirements. Specify the required number of pairs, overall length per drum, and whether the installation zone demands an oil-resistant outer jacket test report. We reply with technical data sheets, shipping weight, and lead times within one working day.

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