The Application Situation Of Center-Palm Type Cable Lug

The center-palm type cable lug purpose is realized when it becomes the interface between a heavy-duty cable and a specific type of connector. Where the simple act of making a connection is a science in its own right is the fascinating world of applied electrical engineering.

A standard electrical lug typically has a barrel (or tube) where the cable is inserted and a "palm" with a single hole for a bolt to pass through. However, different with standard electrical lugs, a center-palm lug’s mounting hole is centered on the axis of the cable barrel.

The symmetrical design provides balanced mechanical support and ensures that the electrical load is distributed evenly across the entire connection point. Otherwise, if the hole is to one side will lead to a twisting moment under high torque or under the stress of thermal expansion and contraction. Therefore, the center-palm design is the preferred choice for high-current and high-reliability applications because of its stability and integrity.

In addition, the specific requirements for the lug is dictated by geometry and function of the connector.

The Straight Connector (The Simple, Direct Path) is the most basic interface with a flat busbar or a terminal block with a single, straight bolt. The center-palm lug’s centered hole aligns perfectly with the bolt hole on the flat surface. In the one hand, the lug sits flush and square when you torque the bolt will create a large surface area contact. In the other hand, it minimizes electrical resistance to minimizes heat generation.

The Elbow Connector (The Space-Saving Turn) is known as a 90-degree or right-angle connector. the connector itself makes the turn is used for the space where is constrained to Instead of a cable bending sharply immediately which can strain the conductors after the lug.

The lug should has a centered palm and mate with a connector whose mounting surface perpendicular to the cable's direction. By the way, its elbow is part of the separate connector piece. Both of all, the lug's job is to provide a flawless and high-pressure interface on that angled surface.

The weight of the cable and the force of the bend can put a pulling or twisting force on the bolt. Therefore, using a lug with the correct palm thickness and material strength is critical to prevent deformation. Additionally, it’s necessary for preventing it from pulling out under mechanical load to ensure the lug is crimped with the correct die and pressure.

Where the center-palm lug's design becomes indispensable is the front & rear connector (The through-panel connection) which refer to the two sides of a feed-through or bushing system. The connector commonly found in metal-enclosed switchgear, pad-mounted transformers, and wind turbine nacelles. In fact, the front & rear connector is typically a PT connector (plug-in terminal connector) or a bushing assembly. Its one side is inside the equipment (rear) and another side is outside (front). As a interlocking system like this ensures a secure and shielded connection through the wall.

Space is often extremely limited in where connects the internal wiring of the unit (e.g., the transformer windings) to the female part of the bushing on the rear side (inside the equipment) .

In addition, the side is exposed to the environment and may require weatherproofing which connects the incoming or outgoing power cable to the male part of the bushing on the front side (outside the equipment). Therefore, a center-palm lug should applied evenly across the connector's interface is force to prevent it from jamming or being damaged during installation or hot-stick switching (a method used by utilities to connect/disconnect under load).