Spotlight on: Sealcon PG Flex Strain Relief Cable Glands

Sealcon PG Flex Strain Relief Fittings: Complete Selection Guide 2025

Spotlight On: Sealcon PG Flex Strain Relief Fittings

Prevent cable kinking, chafing, and premature failure with IP68-rated protection up to 300 feet underwater

150 PSI Liquid-tight rating
300 ft Submersible depth
PG7-PG21 Thread size range
80° Thread angle (vs 60° NPT)

🔧 What Makes PG Flex Fittings Different (And Why It Matters)

The Flexible Advantage

PG flex fittings feature a flexible strain relief neck that prevents two of the most common cable failures:

  • Kinking at entry points
  • Chafing from repetitive movement or vibration

PG Thread vs NPT/Metric: Key Differences

PG Thread (Panzer-Gewinde)
  • Straight thread profile
  • 80° flank angle
  • Shallower thread depth
  • German standard (DIN 40430)
NPT/Metric Thread
  • Tapered (NPT) or straight (metric)
  • 60° flank angle
  • Deeper thread depth
  • US/International standard
⚠️ Important: PG threads are NOT compatible with NPT or metric threads. Always verify your equipment's thread type before ordering.

🎯 Material Selection: Nylon vs Nickel-Plated Brass

Nylon Plastic

Best for: Cost-effective applications

Available Colors: Black Gray
✓ Resistant To:
  • Saltwater
  • Weak acids
  • Alcohol & gasoline
  • Mineral/vegetable/animal oils
🌞 Black Nylon Special Feature:

UL F1 (746C) ozone-stable rating—resists UV fading and cracking. Perfect for solar/photovoltaic installations.

Best Applications:
  • Solar installations
  • Renewable energy
  • Robotics
  • General industrial

Nickel-Plated Brass

Best for: Harsh environments

🌊 Superior Corrosion Resistance

Engineered for extended exposure to harsh chemical and saltwater environments

✓ Key Advantages:
  • Maximum corrosion resistance
  • Higher mechanical strength
  • Better EMI/RFI shielding
  • Longer service life in harsh conditions
Best Applications:
  • Marine & offshore
  • Food & beverage
  • Medical equipment
  • Chemical processing
  • Automotive
💰 Price Point: 2-3x cost of nylon, but 5x longer service life in marine/chemical environments

📏 How to Select the Right Size & Insert

Step 1: Determine Your Thread Size

PG Size Thread OD (mm) Cable Range (mm) Typical Use
PG 7 12.5 3.0 - 6.5 Small sensors, encoders
PG 9 15.2 4.0 - 8.0 Standard sensors
PG 11 18.6 5.0 - 10.0 Control cables
PG 13.5 20.4 6.0 - 12.0 Power cables
PG 16 22.5 10.0 - 14.0 Motor cables
PG 21 28.3 13.0 - 18.0 Heavy-duty cables

Step 2: Choose Your Insert Type

Standard Insert

Full cable diameter range

Use for: Normal-sized cables within spec range

Reduced Insert

Smaller diameter cables

Use for: Cables at low end of size range

Multi-Hole Insert

Multiple small cables

Use for: Running 2-4 small cables through one fitting

💡 Pro Tip: All inserts are swappable. Order extra inserts to increase versatility and reduce inventory costs.

⚙️ Installation in 5 Steps

1
Disassemble Fitting

Remove locknut, seal, and insert

2
Thread Cable

Pass cable through all components

3
Position Insert

Seat insert around cable

4
Tighten Dome & Locknut

Hand-tight + 1/4 turn

⚠️ Critical Installation Rules:
  • Never over-torque nylon fittings—you'll crack the threads
  • Use proper locking nuts for secure installation
  • Verify cable diameter matches insert specification
  • Check seal integrity before final assembly

🔥 Troubleshooting Common Issues

Problem: Fitting Leaking After Installation

Causes:

  • Cable diameter too small for insert
  • Damaged or missing seal/O-ring
  • Locknut not properly tightened
  • Cross-threaded installation

Solutions:

  • ✓ Switch to reduced insert for smaller cables
  • ✓ Replace seal/O-ring (check our Seal & O-Rings collection)
  • ✓ Tighten locknut: hand-tight plus 1/4 turn
  • ✓ Disassemble and reinstall carefully
Problem: Cable Still Kinking at Entry Point

Causes:

  • Bend radius too tight for cable type
  • Flex neck not properly oriented
  • Cable too stiff for application

Solutions:

  • ✓ Consider 90-degree snap-elbow housing
  • ✓ Verify minimum bend radius specification
  • ✓ Use elongated thread version for more flex length
Problem: Cracked Nylon Threads

Causes:

  • Over-torquing during installation
  • Improper locking nut used
  • UV degradation (non-ozone-stable nylon)

Solutions:

  • ✓ Replace with brass fitting for high-torque applications
  • ✓ Use proper Locking Nuts designed for PG threads
  • ✓ Switch to black nylon (ozone-stable) for outdoor use
Problem: EMI/RFI Interference Issues

Causes:

  • Nylon provides no shielding
  • Missing grounding connection

Solutions:

  • ✓ Upgrade to nickel-plated brass fitting
  • ✓ Order EMI/RFI proof version with integrated shielding
  • ✓ Ensure proper grounding of cable shield
🆘 Still Having Issues?

Contact Major Electronix customer service with your cable specifications, environment details, and photos of the installation. Our team can recommend the optimal fitting configuration for your application.

🔧 Specialty Configurations Available

90° Snap-Elbow

Pre-angled housing for tight spaces

Best for:
  • Panel-mounted equipment
  • Space-constrained installations
  • Parallel cable routing

Enlarged/Reduced Housing

Non-standard cable diameters

Best for:
  • Oversized cable jackets
  • Multiple cable bundling
  • Custom cable assemblies

Elongated Thread

Extended thread length

Best for:
  • Thick-walled enclosures
  • Double-wall installations
  • Extra flex length needed

EMI/RFI Proof

Integrated electromagnetic shielding

Best for:
  • Medical equipment
  • High-frequency applications
  • Sensitive instrumentation

📋 Quick Reference Checklist

Before Ordering

  • ✓ Measure cable outer diameter
  • ✓ Verify equipment thread type (PG, not NPT)
  • ✓ Identify environmental conditions
  • ✓ Check for EMI/RFI requirements

Material Selection

  • ✓ Saltwater/marine = Brass
  • ✓ UV/outdoor = Black nylon
  • ✓ Cost-effective = Gray nylon
  • ✓ Shielding needed = Brass or EMI version

Installation Must-Haves

  • ✓ Proper locking nuts
  • ✓ Spare seals & O-rings
  • ✓ Multiple insert types
  • ✓ Torque specifications reference

🏭 Proven Applications Across Industries

🌊 Marine & Offshore

Navigation systems, deck equipment, subsea sensors

☀️ Solar/Renewable

PV panels, inverters, charge controllers

🚗 Automotive

Engine sensors, EV charging, diagnostic equipment

🤖 Robotics

Servo motors, encoders, control systems

⚕️ Medical

Diagnostic equipment, patient monitors, imaging systems

🏭 Industrial

PLCs, VFDs, machine control panels

Ready to Order?

Complete Sealcon PG flex strain relief fittings available at Major Electronix

Need help selecting the right fitting? Contact our customer service team for application-specific recommendations.

Quality Guarantee: Sealcon PG flex strain relief fittings meet IP68 rating standards and are UL, CE, and RoHS compliant.