【Popular‑Science Article】Three Critical Failures of Wiring Terminals! Early Prevention to Eliminate Risks of Complete System Breakdown~
- Categories:Industry News
- Author:Guangdong Deke Electric Co., Ltd.
- Origin://m.hymfwq.com/
- Time of issue:2026-09-08 16:05
- Views:
【Popular‑Science Article】Three Critical Failures of Wiring Terminals! Early Prevention to Eliminate Risks of Complete System Breakdown~
- Categories:Industry News
- Author:Guangdong Deke Electric Co., Ltd.
- Origin://m.hymfwq.com/
- Time of issue:2026-09-08 16:05
- Views:

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As an indispensable connecting component in electrical control systems, wiring terminals fall under the broad category of connectors, whose core function is to establish stable and reliable electrical connection paths. With the comprehensive upgrading of industrial automation and continuously improved control precision of industrial‑control equipment, demand for wiring terminals keeps rising across various industries.
Alongside the iterative development of the electronics industry, terminal varieties have become increasingly diverse. Mainstream products on the market include PCB wiring terminals, metal hardware terminals, nut‑style terminals, spring‑loaded wiring terminals and more, catering to wiring and mounting requirements of different devices.
Many purchasers select terminals merely based on appearance and dimensions while overlooking the vital roles of two core components: the insulating plastic housing and internal conductive metal parts directly determine the overall quality of terminals. The insulator safeguards the insulation safety of the whole equipment, whereas the conductive element undertakes the stable transmission of electric current and signals.
Industrial‑control equipment forms a closed‑loop interactive system, where a slight local defect may trigger system‑wide consequences. Failure of even a single wiring terminal may lead to shutdown of the entire electrical system, signal disorder and even safety accidents. Painful cases of such failures have occurred at industrial sites both at home and abroad.
In electrical maintenance and component management, preventive measures are always more valuable than post‑failure analysis. Identifying root causes of terminal failures in advance and implementing pre‑emptive protection is the key to guaranteeing long‑term stable equipment operation and enhancing component reliability.
DEKEELEC —— —— —— —— —— —— —— —— —— —— —— —— —— —— —— —— ——
Core Operating Principles for Terminals: Conduct When Required, Insulate Where Required
From practical application scenarios, qualified wiring terminals must adhere to two fundamental requirements:
- Conduction Zone : Contact points shall be firmly connected to ensure stable transmission of current and signals without interruption or abnormal contact‑resistance fluctuation.
- Insulation Zone : Non‑conductive areas shall meet specified insulation performance to eliminate electrical hazards such as electric leakage, short‑circuit and dielectric breakdown.
According to field‑maintenance statistics, over 90 % of severe equipment accidents related to wiring terminals stem from three catastrophic failures. The following elaborates their symptoms, root causes and on‑site hazards respectively.
I. Poor Contact: The Most Frequent and Hard‑to‑Detect Latent Failure
Internal metallic contacts serve as the core components of wiring terminals for accurate transmission of input voltage, current and control signals. Long‑term stable conduction relies on well‑designed geometry, durable clamping retention force and superior electrical conductivity of metallic contacts.
Poor contact ranks as the most prevalent terminal failure on‑site. It seldom occurs instantaneously but degrades gradually with strong concealment. Triggering factors span the whole lifecycle including production, storage and operation:
- Production phase : Defective structural design, improper conductor‑material selection, insufficient mould precision, dimensional deviation, sub‑standard plating or heat‑treatment surface processes.
- Assembly phase : Misalignment during manual assembly, abnormal fitting clearance between components.
- Operation phase : Humid and corrosive storage environment, non‑standard field installation, contact loosening caused by prolonged equipment vibration.
Such failure directly drives sharp rise in contact resistance and continuous heating at contact points. Minor consequences include intermittent signals and false equipment alarms; severe outcomes involve contact erosion and complete circuit disconnection.
II. Poor Insulation: High‑Risk Failure Prone to Short‑Circuit and Fire
Insulating housings perform two key functions: positioning metallic contacts and isolating leakage paths between adjacent contacts as well as between contacts and equipment enclosures. As terminals trend toward miniaturization and high‑density layout, wall thickness of insulating housings keeps decreasing, imposing stricter demands on insulation raw materials, injection‑moulding techniques and mould accuracy.
In service, insulation failure is mainly induced by environmental contaminants, material ageing and damp mildew. Residual metal debris inside housings, accumulated surface dust and flux, long‑term moisture absorption and mildewing, natural ageing of insulation materials, together with conductive water films formed by harmful gas deposition, will break down the insulation barrier.
Consequently, serious problems such as electric leakage, phase‑to‑phase short‑circuit and dielectric breakdown may take place. It constitutes one of the major triggers of electrical fires inside industrial‑control cabinets and distribution boxes.
III. Poor Fixation: Structural Failure Causing Direct System Disconnection
Many practitioners mistakenly believe that insulating parts only provide insulation. In fact, terminal housings undertake critical tasks of positioning, locking and anti‑vibration fixation to maintain tight engagement between pins and sockets as well as male‑female mating pairs.
Hazards caused by poor fixation fall into two severity levels. Minor loosening leads to momentary power loss and temporary equipment shutdown‑and‑reset. Severe structural failure results in terminal disintegration and unintended separation of mated male‑female contacts, cutting off power supply and control signals and triggering total paralysis of the whole control system.
Root causes lie in production and installation links, including defective product design, inappropriate raw‑material selection, non‑compliant injection‑moulding and welding processes, and incomplete system‑level assembly.
IV. Two Common Secondary Terminal Failures: Detectable and Rejectable in Advance
Apart from the three catastrophic failures above, two frequent secondary issues can generally be identified and eliminated during incoming inspection or pre‑mount testing, avoiding sudden equipment accidents.
1. Cosmetic Defects Including peeling or oxidation of metallic plating, dents and scratches on contacts, cracking and flash of plastic housings, and deformed conductors. Cosmetic imperfections accelerate subsequent ageing; such units are not recommended for long‑term service conditions.
2. Poor Interchangeability Excessive dimensional tolerances and inconsistent component quality bring about abnormal insertion‑withdrawal force, mis‑alignment of male‑female pairs and locking‑mechanism malfunction. Terminals cannot be universally compatible with connectors of the same specification, impairing on‑site wiring efficiency.
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Though seemingly insignificant small‑size components, wiring terminals act as critical bottlenecks in electrical circuits. Most terminal failures do not occur out of the blue; instead, they result from accumulated hidden risks stemming from raw materials, manufacturing processes, storage and installation.
Performing spot‑checks upon component incoming receipt, standardizing on‑site installation procedures, and controlling temperature‑humidity conditions in storage help avoid the three catastrophic failures at the source, so as to effectively safeguard the operational safety of electrical equipment.

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