What is an Intrinsically Safe SWA Armoured Cable?
- What is an Intrinsically Safe SWA Armoured Cable?
An intrinsically safe SWA (Steel Wire Armour) armoured cable is a specialized hazardous area cable that combines two critical features:
|
Feature |
Purpose |
Benefit |
|
Intrinsic Safety (IS) |
Energy limitation — cannot cause ignition |
Safe for Zone 0/1/2 hazardous areas (gas, vapor, dust) |
|
Steel Wire Armour (SWA) |
Mechanical protection — crush, impact, rodent, tensile |
Survives direct burial, heavy industrial environments, mechanical stress |
The Combination: An IS SWA cable allows you to run intrinsically safe circuits through the most demanding mechanical environments — direct burial, cable trays with heavy traffic, rodent-infested areas, and outdoor installations — while maintaining full hazardous area compliance.
(Cross-section of an intrinsically safe SWA armoured cable for mechanical protection)
At Dingzun Cable, we manufacture intrinsically safe SWA armoured cables with light-blue LSZH sheathing, galvanized steel wire armour, and certified Ex-ia/Ex-ib ratings for hazardous area instrumentation.
- What Makes SWA Different? Steel Wire Armour Explained
SWA (Steel Wire Armour) is a layer of galvanized steel wire applied between the inner jacket and outer sheath of a cable.
Table 1: SWA Armour — Mechanical Protection Specifications
|
Protection Type |
SWA Capability |
Test Method |
Typical Value |
|
Crush Resistance |
Withstands heavy compression and impact |
EN 60811-508 |
>4,000 N/10cm (4,000+ Newtons over 10cm length) |
|
Rodent / Vermin Protection |
Steel wires prevent rodent teeth penetration |
Industry standard |
Steel wires are harder than rodent teeth; prevents cable damage |
|
Tensile Strength |
Withstands pulling during installation |
EN 60811-501 |
>2,000 kg (varies with conductor size and armour thickness) |
|
Impact Resistance |
Survives falling tools, dropped objects, foot traffic |
EN 60811-509 |
>5 Joules (steel wire absorbs and distributes impact energy) |
|
Abrasion Resistance |
Resists wear against rocks, trays, concrete |
Field proven |
Steel wire layer provides durable wear surface before reaching insulation |
Construction of an SWA Armoured Cable (from inside to outside):
|
Layer |
Material |
Function |
|
1. Conductor |
Stranded tinned copper |
Signal transmission |
|
2. Insulation |
PE or XLPE (low Cc) |
Electrical insulation; low capacitance for IS |
|
3. Twisted Pairs |
Blue/black identification |
Noise rejection |
|
4. Shielding (optional) |
Tinned copper braid (≥85%) |
EMI protection |
|
5. Inner Sheath |
LSZH or PVC |
Bedding for armour |
|
6. SWA Armour |
Galvanized steel wire |
Mechanical protection |
|
7. Outer Sheath |
Light-blue LSZH |
IS identification; environmental protection |
At Dingzun Cable, our SWA armoured cables use galvanized steel wire with consistent lay length and coverage, ensuring uniform mechanical protection across the entire cable length.
- Are IS and SWA Compatible? Yes — With Proper Design
Yes, intrinsic safety and steel wire armour are fully compatible — provided the cable is designed and installed correctly.
The Concern: SWA armour is made of steel, a conductive material. Could it store or conduct hazardous energy that compromises intrinsic safety?
The Answer: No — when properly designed and grounded, SWA armour does not affect the IS rating.
(Intrinsically safe SWA armoured cable being installed)
Table 2: IS + SWA Compatibility — Requirements and Compliance
|
Requirement |
Specification |
Why It Matters |
|
Armour is NOT part of the IS circuit |
The steel wire armour is isolated from the IS conductors by the inner sheath |
Armour does not carry IS current; cannot store or release ignition energy |
|
Proper grounding (single point) |
Armour is grounded at one end only (typically safe area) |
Prevents ground loops; ensures armour does not carry stray current |
|
Outer sheath remains light-blue |
RAL 5015 LSZH outer sheath over the armour |
Maintains IS identification per IEC 60079-14 |
|
Documented Cc/Lc values |
Armour affects cable capacitance (Cc) — must be documented |
Entity verification requires accurate Cc values including armour effects |
|
Certified IS rating |
Cable carries Ex-ia or Ex-ib marking |
Third-party or documented compliance with IEC 60079-11 |
Industry Example: As shown in published cable specifications, *"RE-2X(st)H SWAH – instrumentation IS cables"* combine blue sheaths with SWA armouring, meeting both EN 50288-7 (instrumentation cable standard) and IS requirements. These cables are widely used in European hazardous area installations.
At Dingzun Cable, our IS SWA cables are designed with documented Cc and Lc parameters that include the effects of the steel wire armour — ensuring accurate entity calculations for your IS system.
- Key Specifications for Intrinsically Safe SWA Cables
Table 3: IS SWA Cable Technical Specifications
|
Parameter |
Dingzun IS SWA Specification |
Compliance Standard |
|
IS Rating |
Ex-ia (Zone 0/1) or Ex-ib (Zone 1) |
IEC 60079-11 |
|
Armour Type |
Galvanized Steel Wire Armour (GSWA) |
EN 50288-7, IEC 60228 |
|
Crush Resistance |
>4,000 N/10cm |
EN 60811-508 |
|
Tensile Strength |
>2,000 kg (dependent on construction) |
EN 60811-501 |
|
Outer Sheath Color |
Light-blue (RAL 5015) |
IEC 60079-14 |
|
Outer Sheath Material |
LSZH (low smoke zero halogen) |
IEC 61034, IEC 60754 |
|
Inner Sheath Material |
LSZH or PVC |
— |
|
Insulation |
PE or XLPE (low capacitance) |
EN 50288-7 |
|
Conductor |
Stranded tinned copper (Class 2 or 5) |
IEC 60228 |
|
Capacitance (Cc) |
≤150 nF/km (core-core) |
Documented for entity calculation |
|
Inductance (Lc) |
≤0.8 mH/km |
Documented for entity calculation |
|
Temperature Range |
-40°C to +90°C |
— |
|
Flame Rating |
IEC 60332-1, IEC 60332-3-24 |
— |
Pair Count Options:
|
Number of Pairs |
Typical Applications |
|
1 pair |
Single instrument loop (4-20mA transmitter) |
|
2, 4, 8 pairs |
Multiple instruments, control circuits |
|
10, 12, 16 pairs |
Distributed control systems, marshalling panels |
|
20, 24, 50 pairs |
Large instrumentation systems, DCS backbones |
At Dingzun Cable, we manufacture IS SWA cables in 1 to 50+ pair configurations — all with light-blue LSZH outer sheath, galvanized steel wire armour, and documented IS electrical parameters.
- Why Choose SWA Armour for Hazardous Area IS Cables?
SWA armouring is specified when standard IS cables lack sufficient mechanical protection for the installation environment.
Table 4: SWA Armour Applications vs. Standard IS Cables
|
Installation Environment |
Standard IS Cable (Unarmoured) |
IS SWA Armoured Cable |
Selection Rationale |
|
Cable tray (indoor, protected) |
✅ Suitable |
⚠️ May be overkill |
Standard IS cable adequate |
|
Cable tray (outdoor, exposed) |
⚠️ Possible with UV-rated jacket |
✅ Recommended |
SWA provides mechanical protection from weather, maintenance traffic |
|
Direct burial (underground) |
❌ Not suitable (crush risk, rodent risk) |
✅ Required |
SWA withstands backfill compaction and rodent damage |
|
Industrial plant (heavy traffic) |
⚠️ Risk of impact damage |
✅ Recommended |
SWA protects from dropped tools, vehicle traffic |
|
Rodent-infested areas |
❌ PVC/LSZH can be chewed |
✅ Required |
Steel wire prevents rodent penetration |
|
Mining / tunnelling |
❌ High mechanical stress |
✅ Required |
SWA provides crush and impact protection |
|
Outdoor (UV exposed) |
⚠️ Requires UV-stabilized jacket |
✅ Excellent |
SWA + UV-stabilized LSZH provides dual protection |
|
Offshore platforms |
⚠️ Limited mechanical protection |
✅ Recommended |
SWA withstands harsh marine mechanical conditions |
At Dingzun Cable, our engineering team can help you determine whether SWA armouring is necessary for your specific installation environment — balancing cost, mechanical risk, and hazardous area requirements.
- Grounding Requirements for IS SWA Cables
Proper grounding is critical for IS SWA cables to maintain safety and prevent ground loops.
Table 5: IS SWA Cable Grounding Requirements
|
Grounding Element |
Requirement |
Why |
|
SWA Armour Grounding |
Ground at ONE point only (typically safe area at barrier) |
Prevents ground loops that could induce hazardous currents |
|
Shield Grounding (if present) |
Same single point as armour (bonded together at safe area) |
Prevents multiple ground paths |
|
IS Circuit Grounding |
Grounded only through the barrier (isolated from armour) |
Maintains IS energy limitation |
|
Ground Connection Quality |
Low impedance (<1Ω) to true earth ground |
Ensures fault current safely dissipates |
|
Ground Wire Size |
Equal to or larger than largest conductor |
Handles potential fault current |
Critical Warning: Do NOT ground the SWA armour at both ends. Multi-point grounding creates ground loops — induced currents can flow through the armour, potentially introducing hazardous energy into the IS system.
At Dingzun Cable, we provide detailed installation and grounding instructions with every IS SWA cable shipment. Our technical team can also review your grounding plan to ensure compliance with IEC 60079-14.
- Common Applications for IS SWA Armoured Cables
IS SWA cables are specified for hazardous area installations requiring mechanical protection.
Table 6: IS SWA Cable Applications by Industry
|
Industry |
Application |
Why IS SWA is Required |
|
Oil & Gas Refineries |
Direct burial IS instrumentation between process units |
SWA withstands backfill compaction; IS safe for Zone 1/2 |
|
Chemical Processing Plants |
Outdoor cable trays with heavy maintenance traffic |
SWA protects from dropped tools and foot traffic |
|
Pharmaceutical Manufacturing |
Underground conduit between buildings |
SWA prevents rodent damage in buried sections |
|
Mining / Mineral Processing |
Surface and underground instrumentation cabling |
SWA provides impact and crush resistance in heavy industrial environment |
|
Wastewater Treatment |
Digester building to control room cabling |
SWA protects in aggressive, rodent-prone environments |
|
Power Generation (Gas/Coal) |
Plant-wide IS instrumentation backbone |
SWA provides mechanical durability in heavy industrial plant |
|
Fuel Storage / Tank Farms |
Direct burial IS cable between tanks and control room |
SWA required for underground runs; IS safe for Zone 1 around tanks |
|
Offshore Platforms |
IS instrumentation cabling in hazardous areas |
SWA provides mechanical protection in harsh marine environment |
At Dingzun Cable, we have supplied IS SWA cables to projects in all these industries — each with customized pair counts, conductor gauges, and sheath materials to match specific environmental requirements.
- Selection Guide: Choosing the Right IS SWA Cable
Table 7: IS SWA Cable Selection Checklist
|
Parameter |
Your Requirement |
Dingzun Options |
|
Hazardous Area Classification |
Zone 0 / Zone 1 / Zone 2 |
Ex-ia (Zone 0/1), Ex-ib (Zone 1) |
|
Number of Pairs |
_____ pairs |
1 to 50+ pairs |
|
Conductor Gauge |
_____ AWG |
18 AWG to 24 AWG (typical) |
|
Conductor Material |
Bare / Tinned / Silver-plated |
Tinned copper standard; SPC for high temp |
|
Shielding Required |
Yes / No |
Tinned copper braid (≥85%) optional |
|
Installation Method |
Direct burial / Cable tray / Conduit / Outdoor |
SWA required for direct burial |
|
Rodent Risk |
Yes / No |
SWA required if rodent risk present |
|
Outer Sheath Color |
Light-blue (RAL 5015) only |
Light-blue (RAL 5015) — mandatory |
|
Outer Sheath Material |
LSZH / PVC / PUR |
LSZH standard (fire safety) |
|
Temperature Range |
_____ °C to _____ °C |
-40°C to +90°C standard |
|
Certifications Required |
IECEx / ATEX / UL / CSA / Other |
Per target market |
At Dingzun Cable, our engineering team can help you select the optimal IS SWA cable construction based on your hazardous area classification, installation environment, and mechanical protection requirements.
About Dingzun Cable: Your Intrinsically Safe SWA Armoured Cable Partner
With 20+ years of specialized manufacturing experience, Dingzun Cable is a trusted partner for global oil & gas, chemical, mining, and industrial facilities requiring intrinsically safe SWA armoured cables for hazardous area instrumentation. We combine deep hazardous area expertise with extreme customizability to deliver cables that provide both ignition prevention and robust mechanical protection.
(Dingzun Cable Intrinsically Safe SWA Armoured Cable)
Our IS SWA Armoured Cable Capabilities:
|
Capability |
Dingzun Specification |
|
IS Compliance |
IEC 60079-11, IEC 60079-14 — Ex-ia (Zone 0/1), Ex-ib (Zone 1) |
|
Armour Type |
Galvanized Steel Wire Armour (GSWA) |
|
Crush Resistance |
>4,000 N/10cm |
|
Tensile Strength |
>2,000 kg (dependent on construction) |
|
Outer Sheath Color |
Light-blue (RAL 5015) — mandatory per IEC 60079-14 |
|
Outer Sheath Material |
LSZH (low smoke zero halogen) — standard |
|
Inner Sheath |
LSZH or PVC |
|
Insulation |
PE or XLPE (low capacitance, ≤150 nF/km) |
|
Shielding |
Tinned copper braid (≥85% coverage) — optional |
|
Conductor |
Stranded tinned copper (Class 2 or 5) |
|
Number of Pairs |
1 to 50+ pairs |
|
Conductor Gauge |
18 AWG to 24 AWG |
|
Electrical Parameters |
Certified Cc (nF/km) and Lc (mH/km) including armour effects |
|
Temperature Range |
-40°C to +90°C |
|
Flame Rating |
IEC 60332-1, IEC 60332-3-24 |
|
Certifications |
ISO 9001:2015, CE, RoHS, REACH |
|
Testing |
100% electrical testing on every reel |
Why Dingzun Cable for Your IS SWA Armoured Cable Needs:
- Dual protection — Energy limitation (IS) + mechanical protection (SWA)
- Extreme customizability — Pair count, conductor gauge, shielding, armour type, custom printing
- LSZH standard — Low smoke, zero halogen — fire safety without toxic emissions
- Light-blue identification — RAL 5015 sheath with Ex-ia/Ex-ib marking per IEC 60079-14
- Documented IS parameters — Cc and Lc values include armour effects for accurate entity calculations
- Expert engineering team — Support for grounding plans, entity calculations, and installation guidance
- Complete documentation — Test reports, certificates of compliance, installation instructions
[Contact our technical team today for a consultation and custom quote].