Shanghai, China – September 21, 2026 – People always ask: “What type of instrumentation cable is best?” The simple answer: There is no single “best” cable – the right choice depends on your signal type, distance, electrical environment, and industry sector.
Cable Type
Best For
Key Advantage
Limitation
Twisted Pair
4-20mA loops, RTDs, thermocouples, RS485/Modbus
Cancels common-mode noise; cost-effective for analog/digital
Limited high-frequency performance (>10 MHz)
Coaxial
High-frequency signals, video, RF, high-speed data (>10 MHz)
Excellent high-frequency shielding; precise impedance (50/75Ω)
Higher cost; less flexible; not ideal for low-level analog
BS5308
Oil & gas, petrochemical, hazardous areas
Twisted pair + shielding + mechanical protection + IS rating (blue sheath)
Higher cost; heavier; overkill for general industrial
The Bottom Line:
Use twisted pair for most process instrumentation (4-20mA, RS485). Use coaxial for high-frequency or video. Use BS5308 when the specification demands it – typically for oil, gas, and petrochemical projects requiring mechanical toughness and hazardous area certification.
At Dingzun Cable, we manufacture all three types. Our engineering team helps you select based on your signal, environment, and industry standard – not just inventory.
Understanding the fundamental differences is essential for correct selection.
（Instrumentation cable cross-sections）
Table 1: Twisted Pair vs Coaxial vs BS5308 – Key Parameters
Parameter
Twisted Pair (e.g., 4-20mA, RS485)
Coaxial (e.g., RG59, RG6)
BS5308 (Oil & Gas Spec)
Conductor configuration
Two insulated copper wires twisted together
Single center conductor + dielectric + braid/foil shield
Twisted pair(s) + overall shield + mechanical protection
Characteristic impedance
100Ω, 120Ω (RS485), or 150Ω (analog)
50Ω (RF), 75Ω (video), 93Ω (data)
100Ω, 120Ω, or 150Ω (same as twisted pair)
Typical signal type
4-20mA, thermocouple (mV), RTD (resistance), RS485 (digital)
Video (CCTV), RF, high-speed data (>10 MHz)
Same as twisted pair – plus hazardous area (Ex-ia/Ex-ib)
Noise rejection mechanism
Common-mode rejection via twisting
Shield reflection and absorption
Twisting + foil/braid shield + drain wire
Shielding coverage
70-95% (braid) or 100% (foil)
100% (foil + braid typically)
100% foil + braid (composite) typical
Mechanical protection
Moderate (standard jacket)
Moderate to high (depending on construction)
High – often includes GSWA armor, LSZH sheath
Maximum distance (typical)
1,200m (RS485 at low baud); 500-800m (4-20mA)
200-500m (video, depends on signal quality)
Same as twisted pair – plus armor for direct burial
Hazardous area rating
Available (with blue LSZH sheath)
Rare
Common – Ex-ia/Ex-ib with light-blue (RAL 5015) sheath
Relative cost
1.0× (baseline)
1.2-1.5×
1.5-3.0× (depending on armor/certification)
Typical industries
General industrial, manufacturing, water/wastewater
Broadcast, security, telecom, high-speed data
Oil & gas, petrochemical, offshore, mining
At Dingzun Cable, we offer all three configurations with full customization – conductor gauge, pair count, shielding density, jacket material, armor, and hazardous area certification as required.
Twisted pair is the most common instrumentation cable for a reason. The twisting mechanism cancels electromagnetic interference.
Table 2: Twisted Pair – Key Specifications and Applications
Typical Value
Why It Matters
Twists per meter
30-60 twists/m (varies by pair)
More twists = better common-mode noise rejection
100Ω, 120Ω, or 150Ω
Matches termination for RS485 (120Ω) or analog (100-150Ω)
Capacitance (core-core)
≤60-150 pF/m (PE better than PVC)
Lower capacitance = longer possible distance
Shielding options
Unshielded (UTP), foil (ASTP), braid (BSTP), composite (SF/UTP)
Match to EMI environment – see Table 3
Max distance (RS485, 9.6 kbps)
1,200 meters
Longest among copper-based instrumentation
Max distance (4-20mA)
500-800 meters (depends on loop resistance)
Adequate for most plants; longer runs require thicker conductors
Best applications
4-20mA loops, RTDs, thermocouples, RS485/Modbus, general instrumentation
Most common choice for process control
When to Choose Twisted Pair:
If You Need…
Choose Twisted Pair Because…
4-20mA or mV signals
Low cost, adequate shielding, long distance
RS485/Modbus communication
Standard impedance (120Ω) available
Thermocouple extension
Special alloys available (Type J, K, T, etc.)
General plant instrumentation
Most cost-effective solution
Long runs (up to 1,200m)
Lower capacitance (PE insulation) enables long distance
At Dingzun Cable, we manufacture twisted pair instrumentation cables in 1 to 100+ pair configurations, with PE or XLPE insulation for low capacitance, and foil, braid, or composite shielding.
Coaxial cable is designed for high-frequency signals where impedance control is critical.
Table 3: Coaxial Cable – Key Specifications and Applications
Must match source and load to prevent reflection
Center conductor
Solid or stranded copper, copper-clad steel (CCS)
Determines attenuation and flexibility
Dielectric
Solid or foam PE (lower attenuation)
Foam PE has lower loss but less crush resistance
Shielding
Single braid, dual braid, foil + braid, or solid tube
Dual/composite for high EMI environments
Attenuation (typical RG59)
16 dB/100m @ 100 MHz
Higher frequency = higher loss; limits distance
Max distance (analog video)
200-500m (with proper signal quality)
Depends on cable quality and signal level
CCTV, RF transmission, high-speed data (>10 MHz), broadcast
Not for 4-20mA or low-level analog
When to Choose Coaxial:
Choose Coaxial Because…
Video (CCTV, analog/IP over coax)
Standard impedance (75Ω) for video
Radio frequency (RF) signals
Standard impedance (50Ω) for RF
High-frequency data (>10 MHz)
Superior high-frequency performance vs twisted pair
Long high-frequency runs
Lower attenuation than twisted pair at high frequencies
Precision impedance control
Coaxial has tight impedance tolerance (e.g., 75Ω ±3Ω)
At Dingzun Cable, we manufacture coaxial cables in 50Ω and 75Ω variants, with single, dual, and composite shielding – suitable for CCTV, RF, and high-speed data applications.
BS5308 is a British standard specifically for instrumentation cables in the petrochemical industry. It is not a fundamentally different electrical design – it adds mechanical robustness and hazardous area compliance.
Table 4: BS5308 Instrumentation Cable – Key Features
Feature
BS5308 Requirement
Why It Matters for Oil & Gas
Construction
Twisted pair(s) + individual screening (foil) + overall screen (braid)
Maximum EMI protection in high-noise environments (VFDs, pumps, switchgear)
Optional SWA (steel wire armor) or braid
Resists crushing, impact, rodent damage – required for direct burial, heavy industrial
Sheath color
Light-blue (RAL 5015) for IS circuits (per IEC 60079-14)
Immediate identification of intrinsically safe circuits
IS rating
Ex-ia (Zone 0/1) or Ex-ib (Zone 1) common
Safe for hazardous areas with flammable gases/vapors
Flame retardancy
IEC 60332-1 or IEC 60332-3 (bundled)
Prevents fire spread in cable trays and risers
LSZH
Low smoke zero halogen optional (BS5308 Part 2 Type 2)
Required for enclosed spaces (platforms, control rooms, tunnels)
Oil & gas (onshore/offshore), petrochemical, refining, chemical plants
Specification often mandated by engineering contractors (e.g., Shell, BP, Total)
BS5308 Part Classification:
Part
Description
Typical Use
BS5308 Part 1
PVC insulated, PVC sheathed
General purpose (non-LSZH)
BS5308 Part 2
PVC insulated, LSZH sheathed
Fire-safe, low smoke (offshore, enclosed areas)
Type 1
Individual and overall screening
Standard EMI protection
Type 2
Overall screening only (no individual pair screen)
Lower cost, less demanding EMI
When to Choose BS5308:
Choose BS5308 Because…
Oil & gas project specification
Often mandated by engineering spec (client requirement)
Hazardous area (Zone 1/2) IS circuits
Light-blue sheath, Ex-ia/Ex-ib rating, documented Cc/Lc parameters
Direct burial or heavy industrial
SWA armor available
Fire safety (low smoke, zero halogen)
Part 2 LSZH construction
Refinery, chemical plant, offshore platform
Standard in these industries – known, accepted, trusted
At Dingzun Cable, we manufacture BS5308 compliant instrumentation cables (Part 1 and Part 2, Type 1 and Type 2) with full certification – including SWA armor, LSZH sheathing, light-blue IS identification, and documented entity parameters for hazardous area compliance.
Use this decision framework to select the right cable type.
Table 5: Instrumentation Cable Selection Decision Flow
Question
Yes →
No →
Is the signal high-frequency (>10 MHz) or video?
Coaxial (50Ω or 75Ω)
Continue
Is the signal 4-20mA, thermocouple, RTD, or RS485 (≤10 MHz)?
Reconsider signal type
Is the project in oil & gas, petrochemical, or offshore?
BS5308 (or client may specify another standard like IEC 60092)
Does the specification require BS5308, SWA armor, or hazardous area (Ex-ia/Ex-ib)?
Is cost the primary driver and environment is general industrial?
Twisted pair (unshielded or foil/braid as needed)
Is the environment electrically noisy (VFDs, motors, welders)?
Twisted pair with composite shield (foil + braid)
Twisted pair with basic shield (foil or braid)
(Instrumentation cable selection for a customized flowchart for your project)
Practical Examples:
Application
Recommended Cable
Why
4-20mA pressure transmitter in general plant
Twisted pair (foil shield)
Cost-effective; adequate for moderate EMI
RS485 network in VFD-heavy factory
Twisted pair (composite shield + 120Ω impedance)
Protects against broadband EMI
CCTV camera in industrial plant
Coaxial (75Ω, dual shield)
Standard for analog video; good shielding
Instrumentation in oil refinery (Zone 1)
BS5308 Part 2 Type 1 (LSZH, Ex-ib)
Meets spec; IS rating; fire safety
Direct burial IS cable in petrochemical plant
BS5308 with SWA armor + light-blue LSZH
Mechanical protection + hazardous area compliance
High-speed data acquisition (>10 MHz)
Coaxial or shielded twisted pair (depending on interface)
Match to transceiver requirement
At Dingzun Cable, we provide a free selection consultation with a flowchart customized to your project requirements. Contact our engineering team with your signal type, environment, and any industry standards.
Selection Factor
Best for signal type
4-20mA, mV, RTD, RS485
Video, RF, high-speed data
Same as twisted pair + hazardous area
Typical impedance
100-150Ω
50Ω or 75Ω
100-150Ω (same as twisted pair)
Max distance
1,200m (RS485 low baud)
200-500m (video)
Same as twisted pair (plus armor for burial)
EMI protection
Good to excellent (depending on shield)
Excellent (high-frequency)
Excellent (composite shield typical)
Mechanical toughness
Moderate
Moderate to high
High (SWA armor optional)
Hazardous area (IS) rating
Available (blue sheath)
Common (light-blue, Ex-ia/Ex-ib)
Low to moderate
Primary industry
General industrial, manufacturing
Broadcast, security, high-speed data
Oil & gas, petrochemical, offshore
At Dingzun Cable, we manufacture all three types with full customization – including BS5308 certification, SWA armor, LSZH sheathing, and hazardous area (Ex-ia/Ex-ib) ratings. We help you select based on your signal, environment, and industry standard – not just what is in stock.
About Dingzun Cable: Your Instrumentation Cable Engineering Partner
With 20+ years of specialized manufacturing experience, Dingzun Cable is a trusted partner for global industrial projects, oil & gas facilities, and general manufacturing plants requiring high-quality instrumentation cables – including twisted pair, coaxial, and BS5308 certified types. We combine deep signal integrity expertise with extreme customizability to deliver cables that match your exact application.
(Dingzun Cable instrumentation cables)
Our Instrumentation Cable Capabilities:
Capability
Dingzun Specification
Cable types
Twisted pair (UTP/STP), Coaxial (50Ω/75Ω), BS5308 Part 1 & 2 (Type 1 & 2)
Twisted pair pairs
1 to 100+ pairs
Conductor gauge
18 AWG to 24 AWG
Conductor material
Bare copper, Tinned copper
Insulation
PE (low capacitance), PVC, XLPE
Foil (100%), braid (70-95%), composite (foil+braid)
BS5308 features
Individual + overall screen, SWA armor, LSZH sheath, light-blue (RAL 5015)
Hazardous area
Ex-ia (Zone 0/1), Ex-ib (Zone 1) – documented Cc/Lc parameters
Impedance (twisted pair)
100Ω, 120Ω ±5Ω (RS485), 150Ω
Impedance (coaxial)
50Ω ±2Ω, 75Ω ±3Ω
Certifications
ISO 9001:2015, UL, CE, RoHS, REACH, BS5308 compliance
Testing
100% electrical testing on every reel
Why Dingzun Cable for Your Instrumentation Cable Needs:
About Us
We are a national-level high-tech enterprise with 20 years of experience in manufacturing electrical wires and cables, focusing on innovation and technological advancement. Throughout two decades, we have gained extensive expertise and knowledge, dedicating ourselves to delivering high-quality products and services to our esteemed customers.
Media ContactCompany Name: Shanghai Dingzun Electric & Cable Co., Ltd.Contact Person: Media RelationsEmail: Send EmailCountry: ChinaWebsite: https://www.dingzuncable.com/
