What are cable lugs?
Cable lugs, also called cable terminals are devices that are utilized to terminate or connect cables to electrical devices, power or control panels, junction boxes, equipment, and machinery. These lugs are also used to join power cables together.
Cable lugs are often protected with a safety covering shocks and also to avoid damage to the cable lugs and connectors and to prevent short circuit.
Cable Lugs ensure the safety of both, appliances as well as human beings. A cable lug can be uniquely designed according to its requirements and needs.
Types of Cable Lugs
Cable lugs are classified on the basis of their use and applications.
Compression Cable Lugs
Compression cable lugs are used in crimping. Compression cable lugs are of various standards. Compression Cable lugs are instruments used for connecting cables to electrical appliances, other cables, surfaces, or mechanisms. Designed to be easily installed and removed for repairs or maintenance, cable lugs area generally used when permanent, direct-fastening methods are not feasible or available.
2. Mechanical Cable Lugs
Mechanical cable lugs are used for larger, multi-range conductor cross-sections, even for terminating conductors of up to 1 kV cables. Generally, a mechanical cable lug is tinplated and offered with different palm holes, just like compression cable lugs. Mechanical cable lugs can be bolted with 2 screws or 4 screws.
3. Aluminium Cable Lugs
The internal surface of an aluminium cable lug is protected with an oil coating, i.e. a specific grease with an exceptionally high dropping point to keep the aluminium in the lug safe from oxidation and solid construction cable lugs are water-blocked without inspection holes and suitable for both indoor and outdoor applications.
Aluminium cable lugs are designed for various engineering applications and are available in various specifications.
4. Copper Cable Lugs
Copper lugs are ideal for large gauge applications for power draw or grounding. Each copper lug can be either crimped or soldered to wire. The copper lug features a burr-free appearance for an aesthetically pleasing finish.
One end of the copper lug accommodates the cable using a soldering, welding or crimping method, depending on the type of lug. The other end of the copper lug is fastened to a matching terminal or connection point using a bolt, screw or spring clip.
For multiple connection purposes, copper ring type lugs are commonly used. Many of the devices are connected with cables using copper cable lugs.
- Copper lugs are used for terminating cables where vibration is critical.
- Used in industrial segments like
- Distribution board, etc.
5. Bi-metallic Cable Lugs
Bimetallic Lugs are used where an aluminium cable has to be terminated by a copper bus bar or copper contact. If cable lugs of only copper or aluminium are used, a galvanic action occurs due to dissimilar contact. Hence, bimetallic lugs are a technically sound and durable joint. The aluminum barrel is friction welded to the copper palm thereby achieving the best possible transition between barrel & palm.
Here are a few types of bi-metallic cable lugs:
- Aluminum-Copper Bi-Metal Terminals With Copper Palms
- Aluminum Tin Copper Plating Type Bi-metallic
- Aluminum-Copper Bi-Metal Terminals With Copper Ring
- MV (Medium voltage) terminations
- LV (Large voltage) connections on a bus bar
6. Fork-type Cable Lugs
Fork-type cable lugs are used for termination of flexible wires, cords, control cables, meters of control panel or switchboard, contractors, etc, according to its need. These cable lugs are made of high conductivity copper and are generally used for crimping.
The types of fork-type cable lugs are as follows:
Fork-type cable lugs are used in:
- Shipbuilding industry
- Gas industry
- Power industry
- Valve industry
- General pipes connecting projects, etc.
Selection Criteria For A Cable Lug
A range of cable lugs is available for its diverse applications. While choosing a cable lug for an application the following criteria must be considered:
- The type of metal used in the conductor i.e. copper or aluminum.
- The cross-sectional area of the conductor to be terminated or joined.
- Form of the conductor i.e. solid, stranded, compacted or multistranded (trailing/welding cable).
- The size of the securing bolt or stud.
- Product range available, quality and performance approvals.
For instance, in the power distribution industry, tube crimping lugs are used. Since high voltage power is passed through them, most of the connectors used for connection purpose should have a thick layer of insulation. Some use copper tubular lugs for the same. Thus, the material of the lug should be chosen based on its usage.
Another example is that of the wiring and electrical sector where cable lugs have wide applications. Strength of a lug should be checked before using it in the heavy-duty applications. In many applications the strength as well as the shape of lugs matters.