The anatomy of a cable gland consists of several key components, each with specific functions that contribute to its ability to secure, seal, and protect cables. Understanding these components is essential for selecting and installing the right cable gland for a particular application. Here’s a breakdown of the main parts in a typical cable gland:
1. Cable Seal (Inner Seal)
- The cable seal, also known as the inner seal, provides the primary seal around the cable. It grips the outer sheath or insulation of the cable, creating a watertight or dust-tight barrier.
- This part is crucial for ensuring that no moisture, dust, or contaminants can enter the gland and affect the internal connections.
2. Clamping or Armor Clamping Mechanism
- In armored cable glands, this clamping mechanism holds the armor in place. It securely grips the cable’s armor layer, offering strain relief and grounding where necessary.
- This component also protects the cable from being pulled or twisted, which can be especially important in high-vibration environments.
3. Entry Thread
- The entry thread is the threaded section of the gland that allows it to be mounted to equipment, junction boxes, or enclosures. It can be in various thread standards, such as metric, NPT (National Pipe Thread), or PG (Panzergewinde).
- Different thread types are used depending on the region, industry standards, and compatibility with existing equipment.
4. Body or Main Gland Body
- The main body, often made of metal or plastic, houses most of the gland’s components. It provides mechanical protection and is the structural base of the gland.
- This part also determines the cable gland’s size and contributes to its strength, shielding, and overall durability.
5. Locknut and Washer
- The locknut and washer are used to secure the gland to a panel or enclosure. The locknut keeps the gland tightly attached to the mounting surface, preventing it from loosening or twisting.
- The washer provides a seal between the gland and the enclosure surface, contributing to the gland’s ingress protection (IP) rating.
6. Outer Seal (Environmental Seal)
- The outer seal, also known as the environmental seal, encases the cable where it exits the gland. It is usually made of rubber or other flexible, durable material that can form a tight seal around the cable.
- This seal helps maintain environmental protection (such as IP68 or IP69 ratings) by preventing dust, water, and other contaminants from entering the enclosure.
7. Gland Nut (Sealing Nut)
- The gland nut, or sealing nut, is typically the last part that is tightened after installing the gland. Tightening this nut compresses the inner and outer seals to grip the cable securely and maintain a seal around it.
- This component allows for adjustable compression, ensuring a secure fit for different cable diameters.
8. Grounding Ring or Earthing Ring
- Some cable glands include an additional component called a grounding ring or earthing ring, especially for EMC or armored cable glands. This part ensures electrical continuity between the cable armor and the gland, providing a secure path to ground.
- The grounding ring is essential in applications where electromagnetic compatibility (EMC) is a concern, as it helps prevent electromagnetic interference.
9. O-Ring or Seal Gasket
- The O-ring or seal gasket, typically positioned on the entry thread, provides an additional layer of sealing between the gland and the enclosure.
- It helps improve the ingress protection rating by preventing contaminants from entering through the mounting hole.
Summing Up the Components
The specific combination of these components can vary based on the cable gland type, its intended application, and the protection level required. Here’s a summary of typical cable gland components and their functions:
| Component | Function |
|---|---|
| Cable Seal (Inner Seal) | Seals the cable interior to protect against dust and moisture. |
| Clamping Mechanism | Secures the armor in armored glands; provides strain relief. |
| Entry Thread | Attaches the gland to an enclosure or device; available in various thread types. |
| Main Body | Structural part of the gland; provides protection and durability. |
| Locknut and Washer | Secures gland to the mounting surface, ensuring a tight seal. |
| Outer Seal (Environmental Seal) | Provides environmental protection; prevents contaminants entry. |
| Gland Nut | Compresses seals around the cable for a tight, secure fit. |
| Grounding Ring | Ensures grounding and EMC compliance where needed. |
| O-Ring | Adds extra sealing on the entry thread to enhance IP rating. |
Each part works together to create a reliable, durable, and protective connection for cables in various environments, ensuring the cable remains secure, grounded, and sealed against environmental factors.