In recent years, lead times for transformers, switchgear, and critical grid components have steadily increased. For many factories, data centers, power distribution projects, and retrofitting initiatives, waiting for a major core component can necessitate schedule adjustments spanning months or even longer. Public reports indicate that delivery times for large transformers and certain high-voltage equipment have become a significant bottleneck in the completion of power projects.
Faced with the immense pressure of massive financial losses resulting from production shutdowns, many factories have been forced to resort to “long-term operation with defects” or “makeshift on-site wiring.” However, what truly drives operations and maintenance teams to a breaking point is often not the major equipment itself, but a seemingly trivial issue: a mismatch in connections.
Unable to source replacement parts with exact specifications, sites are often left with a stockpile of standard crimp lugs that do not match the gauge of urgently procured cables. To meet tight deadlines, extremely dangerous “forced-fit” workarounds are frequently employed:
If a large-gauge wire won’t fit into a small lug, workers might “shave off a few strands” of the copper or aluminum core to force it in for crimping;
If a small-gauge wire fits too loosely in the lug barrel, workers might insert a copper shim to fill the gap and secure the connection.
This practice—akin to “trimming the toes to fit the shoe”—poses a severe threat to electrical safety!
Shaving the wire core compromises the cable’s original isotropic properties and electric field distribution, while inserting copper shims creates numerous internal air gaps. Under the stress of sustained high electric field intensity and thermal cycling, these loose connections and sharp edges can trigger intense partial discharge (PD), leading to “electric treeing” that penetrates the insulation and ultimately results in phase-to-phase short circuits or violent explosions.
Engineering a Breakthrough: From “Rigid Matching” to “Flexible Connection”
Traditional crimping technology demands a precise match between the cable, the lug, and the crimping die. However, in today’s fragile supply chain environment, the margin for error in such “rigid matching” systems is far too slim. In contrast, shear bolt connectors
offer significant advantages for on-site emergency repairs and standardization:
Wide Application Range: Thanks to a stepped or stepless bolt advancement design, a single connector size can accommodate multiple cable cross-sections (e.g., 185–400 mm²), eliminating the need to take risks due to wire-size mismatches during emergencies;
Constant Contact Force and Electric Field Smoothing: The shear bolts snap off automatically upon reaching the preset torque, ensuring consistently low contact resistance; furthermore, the smooth, burr-free break point significantly reduces local electric field concentration at the stress control sleeve (stress cone);
Elimination of Human Error: This method removes reliance on a worker’s “feel” for crimping or specific die sizes, ensuring that every installation meets electrical performance standards, even in harsh emergency repair environments.
Recommendations for On-Site Operations and Maintenance
While the “winter” for supply chains may persist, the fundamental electrical safety standards for on-site operations must not be compromised by makeshift connections. For sites forced to operate with compromised components or requiring urgent temporary re-connections, engineering teams should adopt the following safeguards:
Optimize Spare Parts Inventory: Gradually upgrade traditional crimp-type inventory to multi-range shear bolt connectors to enhance operational flexibility when facing unexpected changes in cable sizes;
Strengthen Live Diagnostics: Implement ultrasonic/high-frequency partial discharge (HFCT PD) testing and infrared thermography for all joints involving temporary re-connections or a history of conductor trimming, designating them as high-priority monitoring targets;
Strictly Prohibit Non-Standard Practices: Explicitly ban practices such as trimming conductor strands or inserting copper shims in on-site Standard Operating Procedures (SOPs) to prevent catastrophic power outage losses—costing millions—caused by minor, improper shortcuts.
In the face of uncontrollable delivery schedules, standardized connection techniques and versatile, standardized hardware serve as the critical final line of defense for the safety of the power distribution network.
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