Cable gland plates are indispensable components in machinery installations. These specialized plates, featuring strategically placed cable entry points, ensure the secure and efficient routing of electrical cables while maintaining the integrity of the enclosure.

This comprehensive guide will delve into the purposes of cable gland plates, including ingress protection, strain relief, and EMC. We will explore the various types and materials available, and provide guidance on selecting the optimal plate for your specific application.

What is a Cable Gland Plate

A cable gland plate, also known as a gland plate or entry plate, is a flat metal plate that provides a secure interface for cable glands to enter and exit an enclosure.

Cable gland plates are designed with pre-drilled, threaded holes that allow cable glands to be securely fastened. The cable glands, in turn, provide a sealed entry point for cables passing through the enclosure wall. This setup enables cables to be routed into and out of enclosures like junction boxes, control panels, and machine casings without compromising the enclosure’s sealed environment.

Purposes of Cable Gland Plates

• Maintaining Ingress Protection (IP) Rating: Cable gland plates, when properly installed with compatible cable glands, help maintain an enclosure’s Ingress Protection rating.
• Cable Entry and Exit: Cable gland plates provide a means to organize and manage multiple cables entering and exiting an enclosure. The structured layout of the plate, with designated holes for each gland, allows cables to be neatly arranged and labeled.
• Strain Relief: Cable gland plates, in conjunction with cable glands, provide strain relief for cables. When cables are secured within the gland, any pulling force or mechanical stress is transferred to the gland plate instead of the cable itself.
• Electromagnetic Compatibility (EMC): Conductive gland plates, when properly grounded, can help shield against electromagnetic radiation entering or exiting the enclosure via the cable entry points.

Types of Cable Gland Plates

Pre-drilled Plates

Pre-drilled cable gland plates come with pre-punched holes of various sizes to accommodate different cable glands. These plates streamline installation by eliminating the need for drilling on-site, saving time and effort. Pre-drilled plates are available in standard configurations to fit common enclosure sizes and cable gland arrangements.

Blank Plates

Blank cable gland plates offer flexibility for customized cable entry configurations. These plates are supplied as solid sheets without any pre-drilled holes. They allow engineers and installers to drill holes according to specific project requirements, accommodating unique cable sizes, quantities, and layouts.

Membrane Plates

Membrane cable gland plates feature a flexible, elastic membrane that allows cables to pass through while maintaining a tight seal. The membrane material, typically silicone or TPE, stretches to accommodate cables of different diameters without the need for individual holes. They provide excellent ingress protection, preventing dust, moisture, and other contaminants from entering the enclosure.

Materials for Cable Gland Plates

Aluminum

Aluminum cable gland plates are lightweight, cost-effective, and provide good corrosion resistance in most environments. Aluminum plates can be easily machined and drilled, making them suitable for customization. However, they may not be the best choice for harsh environments with extreme temperatures or exposure to corrosive substances.

Stainless Steel

Stainless steel cable gland plates offer superior strength, durability, and corrosion resistance. They are ideal for demanding applications in harsh environments, such as food processing, chemical plants, and offshore installations. Stainless steel plates withstand high temperatures, resist chemical attacks, and provide excellent protection against mechanical impact.

Brass

Brass combines good mechanical strength and corrosion resistance with excellent machining properties. It performs well in outdoor and marine environments. However, brass plates are heavier and more expensive than aluminum.

TPE

Thermoplastic Elastomer (TPE) plates offer a lightweight, flexible option. They resist weathering, chemicals, and provide high ingress protection. TPE is suitable for applications with vibration or frequent cable changes, but may not be as robust as metal plates.

How to Select the Right Cable Gland Plate

1. Cable Type and Size: Select a plate with holes or membrane suitable for the cable diameters used. Consider if shielded or armored cables need special gland types.
2. Application Environment: Choose a plate material that withstands environmental conditions like moisture, corrosive chemicals, UV exposure, or extreme temperatures. Outdoor settings may require better corrosion resistance.
3. Enclosure Type: Ensure the plate fits the enclosure’s shape, size, and available space for cable entry and glands. Consider if additional features like knock-outs are needed.
4. Material Compatibility: Verify that plate and gland materials are galvanically compatible to avoid corrosion. Confirm the plate material is suitable for mating with the enclosure.
5. Cable Gland Size and Thread Type: Pick a plate with appropriate sized holes and thickness for the cable glands used. Hole threads must match the gland thread type.
6. Multi-Hole Bushings: For multiple smaller cables, bushings or multi-hole inserts can bundle them through one larger plate opening. This optimizes space and hole usage.