Engineered Double & Single Compression Assemblies
Tested to IP68, UL, and explosion-proof classifications across harsh process environments.
Anatomy of Double Compression vs Single Compression Mechanics
Understanding how dual elastomeric seals and precision armor cone clamping protect mission-critical equipment against moisture ingress, vapor migration, and mechanical tension.
Inner Seal Barrier
The inner sealing ring compresses uniformly against the inner cable bedding or jacket. In hazardous locations (Zone 1/21, Class I Div 1), this creates an explosion-proof gas seal that prevents internal flames or gas migration along the cable interstitial spaces.
- Material: Chloroprene, NBR, or High-Temp Fluorocarbon (FKM)
- Ingress: Direct vapor and liquid barrier down to IP66/IP68
- Flamepath: Precision radial clearance according to IEC 60079-1
Armor Clamping Cone & Ring
Engineered for Steel Wire Armored (SWA), Steel Tape Armored (STA), Aluminum Wire Armored (AWA), or braided cables. The precision cone securely locks the metallic armor, offering over 450N to 2000N of mechanical pull-out resistance.
- Earth Continuity: Low electrical impedance bonding (< 0.1 mΩ)
- Zero Twisting: Clamping cone prevents rotational torsion during tightening
- Armor Wire Range: 0.2mm wire braid up to 3.15mm heavy SWA wires
Outer Environmental Seal
Positioned under the compression outer nut, the second seal compresses onto the cable's external sheath. It shields the internal armor clamp from atmospheric chlorides, UV degradation, industrial acid fumes, and pressurized washdown jets.
- Protection Rating: Tested under 10 bar water pressure (100m depth)
- Environmental: Compliant with IP68 / IP69K dynamic washdown
- Temperature Range: Stable operation from -60°C to +130°C
Standard Double Compression Sizing Matrix (Metric & NPT)
Engineers and buyers can cross-reference cable diameters, armor thickness, entry thread pitch, and spanner sizes before downloading the complete technical PDF datasheet.
| Gland Size Ref. | Entry Thread (Metric) | Alternative (NPT) | Inner Sheath Bedding (mm) | Armor Wire Dia. Range (mm) | Outer Cable OD (mm) | Hexagon A/F (mm) | Thread Length (mm) | Cert. Class |
|---|---|---|---|---|---|---|---|---|
| DC-20S/16 | M20 × 1.5 | 1/2" NPT | 3.1 – 8.6 | 0.15 – 0.35 / 0.8 – 1.25 | 6.1 – 13.2 | 24.0 / 26.5 | 15.0 | Ex d IIC / UL |
| DC-20 | M20 × 1.5 | 1/2" NPT | 6.1 – 11.6 | 0.20 – 0.45 / 0.9 – 1.25 | 9.5 – 15.9 | 27.0 / 30.0 | 15.0 | Ex d IIC / UL |
| DC-25 | M25 × 1.5 | 3/4" NPT | 11.1 – 17.5 | 0.20 – 0.45 / 1.2 – 1.60 | 15.5 – 22.0 | 36.0 / 38.5 | 15.0 | Ex d IIC / UL |
| DC-32 | M32 × 1.5 | 1" NPT | 17.0 – 26.3 | 0.30 – 0.55 / 1.6 – 2.00 | 22.0 – 29.8 | 46.0 / 50.0 | 15.0 | Ex d IIC / UL |
| DC-40 | M40 × 1.5 | 1-1/4" NPT | 23.5 – 32.2 | 0.30 – 0.55 / 1.6 – 2.00 | 27.9 – 40.4 | 55.0 / 60.0 | 15.0 | Ex d IIC / UL |
| DC-50S | M50 × 1.5 | 1-1/2" NPT | 31.5 – 38.2 | 0.40 – 0.60 / 2.0 – 2.50 | 35.2 – 46.4 | 65.0 / 70.0 | 15.0 | Ex d IIC / UL |
| DC-50 | M50 × 1.5 | 2" NPT | 35.6 – 44.1 | 0.40 – 0.60 / 2.0 – 2.50 | 40.4 – 53.1 | 70.0 / 75.0 | 15.0 | Ex d IIC / UL |
| DC-63S | M63 × 1.5 | 2" NPT | 41.5 – 50.0 | 0.50 – 0.80 / 2.0 – 2.50 | 45.6 – 59.4 | 80.0 / 88.0 | 15.0 | Ex d IIC / UL |
| DC-63 | M63 × 1.5 | 2-1/2" NPT | 47.2 – 56.0 | 0.50 – 0.80 / 2.5 – 3.15 | 54.6 – 65.9 | 85.0 / 92.0 | 15.0 | Ex d IIC / UL |
| DC-75 | M75 × 1.5 | 3" NPT | 59.0 – 68.0 | 0.60 – 1.00 / 2.5 – 3.15 | 66.7 – 78.5 | 99.0 / 108.0 | 15.0 | Ex d IIC / UL |
China Factory 4.0: Supply Chain Resilience & Lean Advantages
Operating from Liushi, Yueqing—the epicentre of global electrical apparatus manufacturing—our facility integrates automated Swiss-type CNC lathing, in-line optical inspection, and tight raw material vertical integration.
Automated Multi-Spindle CNC
Every cable gland body, cone, and entry thread is machined on high-precision multi-axis Swiss-type CNC centers. Dimensional tolerances are held within ±0.015mm, guaranteeing exact thread engagement and hermetic seating.
100% Optical Sorting & Gauge QC
Automated visual sorting systems inspect every internal and external thread profile for burrs, pitch micro-deviations, and surface defects before surface treatment (bright nickel electro-plating or passivation).
Direct Metallurgy Traceability
Certified HPb59-1 / CuZn39Pb3 brass billets and AISI 304 / 316L / 316Ti stainless steel ingots are sourced directly from ISO 9001 certified mills, with EN 10204 3.1 chemical and tensile inspection reports archived per batch.
Application Engineering Across Severe Environments
Where cable integrity directly correlates with plant uptime, personnel safety, and environmental stewardship.
Oil & Gas (Onshore/Offshore)
Engineered for hazardous upstream drilling rigs, FPSO vessels, and downstream refineries. Ex d flameproof barrier designs withstand blast pressure waves and hydrocarbon fluid splashes.
Offshore Wind & Subsea
Fabricated in Marine Grade 316L Stainless Steel with over 1000 hours salt-spray resistance (ASTM B117). Resists high mechanical vibration in nacelles and tower power busbars.
Hydrogen & Clean Tech
Micro-crystalline sealing compounds engineered to stop low-molecular H2 permeation, combined with explosion-proof certification for Group IIC gases with extreme combustion velocity.
Rail Rolling Stock & BESS
Fire and smoke compliant with EN 45545-2 HL3. Absorbs high-energy harmonics and vibration spikes in heavy commercial battery energy storage systems (BESS) and locomotives.
Technological Innovations in Next-Gen Cable Terminations
Anticipating emerging megatrends in electrification, telemetry, and non-metallic nano-coatings.
IoT & Condition Telemetry
Development of smart compression glands integrated with micro-piezoelectric torque sensors and thermal couplers. Provides real-time field data regarding loose terminations, ingress moisture spikes, and localized overheating.
Graphene Anti-Corrosion Barriers
Transitioning beyond conventional electrolytic nickel plating to atomic-layer graphene vapor deposition (CVD). Yields a microscopic 5μm barrier that outperforms 304 stainless steel in severe acidic chemical plant washdowns.
Cryogenic -196°C to +250°C Elastomers
Pioneering fluorosilicone and perfluoroelastomer (FFKM) proprietary sealing rings capable of maintaining elasticity in liquefied natural gas (LNG) bunkering hubs as well as aerospace engine test bays.
International Certifications & Harmonized Quality Systems
Every Hoonsun double compression gland series undergoes accredited testing to ensure friction-free approval by EPC audit authorities worldwide.
ATEX / IECEx Certifications
Certified according to EN IEC 60079-0 (General Requirements), EN IEC 60079-1 (Flameproof Enclosures 'd'), and EN IEC 60079-7 (Increased Safety 'e') for Zone 1, Zone 2, Zone 21, and Zone 22 dust and gas protection.
UL 514B & CSA C22.2 No. 18.3
Listed for North American electrical installations adhering to the National Electrical Code (NEC) and Canadian Electrical Code (CEC). Tested under extreme pull-out tensile forces and water spray cycles.
Full Mill Material Traceability
All delivered batches are accompanied by EN 10204 3.1 inspection documentation, complete chemical spectrography, RoHs / REACH declaration of conformity, and ISO 9001:2015 process compliance.
Solving Global Enterprises' Procurement Challenges
How Tier-1 engineering contractors optimize Total Cost of Ownership (TCO) through direct OEM/ODM factory partnerships.
35–50% Direct Cost Reduction
By eliminating intermediate European or American distribution markups, EPCs achieve massive margin improvements on major megaprojects requiring tens of thousands of armored gland entries.
OEM Private Labeling & Custom Sizing
Custom entry thread lengths (extended 25mm threads for thick cast-iron explosion-proof enclosures), custom laser marking with your part numbers, and pre-packaged kits with locknuts, washers, and Earth tags.
Rapid Production & Global Logistics
Standard sizes (M20–M63 and 1/2"–2" NPT) maintain safety raw billet inventories in Yueqing for 7–12 days fast-turn air/sea dispatch to Europe, the Middle East, Southeast Asia, and the Americas.
Heavy-Duty & Specialized Industrial Cable Connectors
Factory-direct metal, stainless steel, and specialty waterproof connection hardware.
Frequently Asked Technical Questions (FAQ)
Clear, authoritative technical answers addressing common search intent and specification challenges.
What is the definitive mechanical difference between single and double compression cable glands?
How do I select the right size from the Double Compression Size Chart PDF?
- Bedding Diameter (Inner Sheath OD): Must fall squarely within the gland's inner seal clamping range. If too small, the gland will not seal gas or water; if too large, the inner seal will tear or prevent the gland body from engaging.
- Armor Wire / Braid Thickness: The thickness of the steel wires or tapes must correspond to the clamping cone's specified gap (e.g., 0.9–1.25mm wire vs 0.2–0.45mm braid).
- Overall Cable Outer Diameter (OD): Must sit comfortably within the outer compression seal's min/max threshold.
Are Chinese-manufactured double compression glands certified for ATEX and IECEx Zone 1 hazardous areas?
What torque values should be applied to tighten double compression cable glands?
- M20 / 1/2" NPT: 20–25 Nm on the entry thread; 15–20 Nm on inner and outer compression nuts.
- M25 / 3/4" NPT: 30–35 Nm entry; 25–30 Nm compression nuts.
- M32 / 1" NPT: 45–55 Nm entry; 35–45 Nm compression nuts.
- M50–M63 / 2" NPT: 70–90 Nm entry; 55–70 Nm compression nuts.