Preventing Arcing At Cable Terminals: A Technical Analysis From Contact Resistance To Oxide Layer Treatment

Abnormal temperature rises are frequently encountered during electrical operation, and arcing at the copper lugs terminal is a common cause of power outages. This phenomenon usually stems from the performance degradation of physical connection points. When the pressure between the current-carrying conductor and the connector is insufficient, microscopic unevenness of the contact surface leads to an actual conductive area that is much smaller than the nominal contact area. This contraction resistance effect causes localized heat accumulation, subsequently producing a visible arc or spark.

The Impact of Crimping Process and Torque Control on Connection Quality

Equipment operating over a long period is affected by environmental vibrations and thermal expansion and contraction, making the Aluminum Cable Lug terminal prone to mechanical loosening. Insufficient bolt torque leads to charge accumulation at the gap, breaking down the air medium and causing arcing. Specific failure manifestations encompass the following three dimensions:

• Thickening of the interface oxide layer: Aluminum terminals readily form a high-resistivity oxide film in air; if conductive paste is not applied, heat will increase exponentially.

• Metal fatigue creep: Fasteners undergo plastic deformation under continuous pressure and alternating high temperatures, resulting in loss of clamping force.

• Harmonic current overload: Frequency interference from nonlinear loads increases the skin effect, causing the terminal load capacity to exceed the design threshold.

Practical recommendations for monitoring and maintaining cable terminals:

Daily inspections should focus on the application of infrared thermal imagers. By observing temperature rise curves, early signs of arcing at cable terminals can be quickly identified. If discoloration, unusual odor, or a faint hissing sound is detected, power should be immediately cut off.

During cleaning, the old carbonized layer must be removed. Use hydraulic crimping pliers matching the wire diameter to complete the re-crimping, and add disc spring washers to compensate for thermal stress. When replacing damaged parts, the Compression Cable Lug material must be consistent with the cable conductor to prevent secondary damage from electrochemical corrosion.