Often during installation work with current-carrying supply and power cables, it becomes necessary to use a special device when entering them into distribution cabinets and when using junction boxes with switching rails. Especially acute is the question of using devices to protect the cable from breaking the insulation of creases, bends.
Gland entry
When supply cables of low power enter the switchboards, as well as the box, insulation or cable creases may be damaged, followed by a break in one of the phases. In such cases, a special protective device is used - stuffing box gland. These are special elements necessary for connecting cable products to any type of electrical equipment. Thus, the cable can be safely inserted into any type of enclosure.
Views
Gland entry is primarily divided intotwo types - with and without a clamping mechanism.
In addition, they are divided according to the types of material from which they are made:
- Plastic bushings, namely polyamide, are the most common because of their low cost and increased tightness properties. However, do not forget about some disadvantages, the most significant of which is the possible thread breakage when tightening the lock and clamping nuts, as well as the occurrence of microcracks during operation in hazardous areas where an explosion is possible.
- Metal omental glands do not structurally differ from plastic ones. But at the same time they are more reliable and resistant even when working in explosive areas. They are made of nickel-plated brass and stainless steel.
Design features
Gland gland is a construction of several elements, each of which has a specific function. It has a clamping and locking nut necessary to securely fix both the cable itself and at the junction with the electrical cabinet body. There are also special seals needed to protect against moisture and dust in order to ensure the safe operation of the equipment.
And one of the main elements is a gear coupling, which gives the connection additional strength during installation and operation of electrical equipment.
Application
Cable glands are used not only to protect the cable from direct damage, but alsoto protect the electrical cabinet itself of any kind of equipment from direct dust and moisture. This can protect the electrical installation from a short circuit due to a breakdown between the discharge contacts through dust or moisture.
Another important positive feature is the possibility of rigid fastening of power cables at the cable entry points into electrical cabinets using cable glands. During operation of the equipment, even a well-fixed cable can be damaged. This can be done by both maintenance personnel and those working on this equipment. In this case, the contact at the junction of the supply wires of the cable may be damaged, and a short circuit is also possible due to broken wires falling into adjacent contacts. In some cases, a short to the case occurs, and even a grounded installation can be dangerous when touched. These and other types of nasty open circuits and short circuits put a running plant out of service, disrupt the process, and expose operating personnel to electrical hazards.
Do not forget that even the use of stuffing boxes does not exempt from the mandatory use of grounding in electrical installations. This is strictly regulated in the rules for the installation and operation of power supply cables.
