How to Select Cable Glands

Image Credit: Appleton | Digi-Key

Cable glands are bulkhead modules that allow barrier penetration while providing sealing protection. They are commonly known as sealing glands or strain reliefs and have the ability to seal around one or multiple wires, cables, or probes. Cable glands are sometime configurable to work with any cable within a specified size range. They serve several functions including environmental protection (such as protection against dust and moisture) and additional sealing on the part of the cable entering the enclosure. They are able to facilitate earth continuity in the cases of armored cables, and provide a holding force on the cable to ensure adequate levels of cable pull out resistance. Cable glands can be used on all types of electrical power, control, instrumentation, data and telecommunications cables.

Cable gland installation. Image Credit:simonwillis1972

When selecting a cable gland there are several steps to take in order to ensure the proper cable glad is used in the application. The first step is to identify the type of cable to be used and then check the construction, size, and material properties of the cable.

Cable Gland Specifications

Important specifications to consider when searching for cable glands include cable diameter, mounting hole diameter, and adjustable diameter.

• The wire hole diameter is the maximum diameter of a cable or wire. This should be large enough to house all the cables in the system.
• The pressure rating denotes the amount of pressure a device can withstand without leakage.
• The number of wires the assembly can accommodate is important to consider.

Cable glands. Image Credit: Prism Control Gear

• The cable diameter specifies the diameter of the cable that can be fed through the cable gland.

• The mounting hole diameter refers to the diameter of the barrier or bulkhead hole into which the gland is to be installed.

• The adjustable diameter is the cable gland can be adjusted to fit various sizes of cable.

Mounting Options

Cable gland mounting should be chosen based on the pre-existing connections in the system. Choices for gland mounting include adhesive or compound, flanged or bolted, threaded or nut mount, welded, and cast.

Materials of Construction

Material is a very important specification when selecting a cable gland. The common material types available are aluminum, nylon, PTFE, steel, and stainless steel. The material should be strong enough to perform for the required time in the application. It should also be compatible with the cable material to prevent corrosion, excessive wear, or damages.

Features

There are several features for cable glands including:

• Fire-stop cable glands are designed to withstand fire propagation through a barrier.
• Explosion proof cable glands are designed for some level of explosion safety.
• EMI and RFI shielding and associated grounding features are used to minimize or eliminate electromagnetic (EMI) and radio frequency interference (RFI).
• Romex connections are specifically-designed to retain and sometimes seal around romex cable as it enters a junction box or enclosure.
• Wire mesh is added to connectors to provide additional strain relief.

Wire mesh. Image Credit: Legrand

• Liquid tight cable glands provide protection against the ingress of penetrating water, oils, and other liquids.

Applications

Common applications for cable glands include aerospace, cleanroom, fire protection, industrial, marine, panel or enclosure, power or utility, railway, and telecommunications.