Cable Glands
Cable Glands for Sealed, Strain-Relieved Cable Entry
Cable glands are one of several methods within Galco's cable entries category for sealing and mechanically securing a cable where it enters an enclosure, panel, or junction box. Beyond basic strain relief, a properly selected gland maintains the enclosure's ingress protection (IP) rating, prevents cable abrasion at the entry point, and in some constructions provides grounding continuity or EMC shielding for armored or shielded cable. Selecting the wrong gland is one of the more common causes of a panel failing its IP rating in the field, even when every other component is correctly specified.
The starting point for selection is thread compatibility with the enclosure's mounting hole: NPT (tapered, common in North America), metric M-thread (straight, the global standard for new equipment), and PG (Panzergewinde, a legacy German straight-thread standard still found on older control panels). These threads are not interchangeable, and forcing a mismatched gland into a bore typically strips the threads or compromises the seal. If you're retrofitting older equipment, check the existing thread designation before ordering, since PG and metric threads are dimensionally close enough to cause confusion but won't seal correctly against each other. Galco's cable entry plates and cable entry frame kits are worth considering when an enclosure needs multiple cable entries and drilling individual gland holes isn't practical.
The second selection criterion is the cable's outer diameter against the gland's clamping range, not just the bore size. Every gland has a stated minimum and maximum clamping diameter; cables sized at the edge of that range often seal poorly even though the thread fits. For high-vibration or outdoor installations, IP66/IP68-rated glands with integrated O-ring seals are typically required to maintain enclosure ratings, and armored cable applications need glands designed specifically for armor termination rather than standard unarmored constructions. If sealing requirements extend beyond a single cable entry, cable grommets and frame-gland-grommet modules offer a modular approach for multi-cable panel entries, while brush pass-through frames are suited to applications needing flexible, non-fixed cable routing through an enclosure wall. For broader context on enclosure sealing and thermal management, see Galco's enclosures and thermal management category.
Frequently Asked Questions
How do I know if I need NPT, metric, or PG threads?
Check the existing enclosure or equipment for a thread marking near the cable entry hole. NPT is typically stamped as a fractional inch size (e.g., 1/2" NPT), metric as an "M" prefix with diameter and pitch (e.g., M20 x 1.5), and PG as a "PG" prefix with a number (e.g., PG16). If there's no visible marking, measuring thread pitch and comparing against published charts is more reliable than guessing by diameter alone, since PG and metric sizes can be close enough to misidentify. When replacing a gland on legacy equipment, confirm the original thread type rather than assuming metric, since many older North American and European panels still use NPT or PG respectively. See Galco's full cable entries category for thread-specific options.
What happens if I use a gland with the wrong clamping range for my cable?
A cable near the minimum or maximum edge of a gland's clamping range often fails to achieve proper compression on the seal, which can reduce the effective IP rating even though the gland technically threads into the bore. Undersized clamping also reduces strain relief, increasing the risk of cable pull-out or insulation damage at the entry point over time. When a cable's diameter falls outside standard gland ranges, cable grommets or cable entry plates with split or modular sealing inserts often provide more flexibility than a single fixed-bore gland.
Do I need an armored or EMC cable gland for shielded cable?
Standard cable glands are designed for unarmored cable and don't provide a reliable termination point for cable armor or braided shield. Armored cable requires a gland with a separate clamping mechanism for the armor layer to maintain mechanical integrity and, where required, grounding continuity. EMC-rated glands additionally provide 360° contact with the cable shield to maintain shielding effectiveness through the enclosure wall; substituting a standard gland in an EMC-sensitive application typically reintroduces the interference the shielding was meant to prevent. This distinction matters most in automation and control and networking and communication installations where shielded cable is common.