Power Circuit Reliability

01  Introduction

A low insulation resistance in airport airfield lighting circuits is a common problem faced by airports worldwide and an important hidden risk affecting the safe and stable operation of airfield lighting. Circuits remain for long periods in complex environments with moisture, standing water, freeze-thaw cycles and temperature differences; cable connection points readily take in water because of seal failure, differences in workmanship and ageing, causing insulation performance to decline. In particular, with the widespread use of LED luminaires and individual lamp monitoring systems, the insulation level of the circuit also directly affects control and communication quality.

02  Why Traditional Connection Methods Readily Lead to a Decline in Insulation

· More weak points  → With traditional heat-shrink methods, each luminaire creates 4 potential weak points: the 2 heat-shrink joints of the primary cable connector and the 2 plug-in points between the connector and the isolation transformer. The more luminaires there are, the more potential risk points the circuit has.

· Obvious weakest-link effect  → The overall insulation level of a series circuit is easily governed by the weakest joint; the number of potential weak points rises from 2 to 4, further increasing the risk of a decline in circuit insulation.

· Strong environmental influence  → Complex service conditions such as moisture, standing water, freeze-thaw, temperature differences and cable bending put the sealing and insulation performance of joints under long-term strain.

· Tape ages easily  → External 3M tape exposed for long periods to moisture, temperature differences and freeze-thaw conditions risks ageing, loosening and gradually degrading sealing performance.

· Workmanship depends on the operator  → The heat-shrink process places high demands on operator skill, and differences in workmanship directly affect the final insulation performance of the joint.

· Fault location is difficult  → A single circuit has a very large number of connection points; once insulation declines, locating and troubleshooting the fault point is often time-consuming and labour-intensive.

03  Ten Years of Development: One-Shot Potting Replaces the Heat-Shrink Process

Addressing the long-standing problem of low insulation in airport lighting circuits, AIRSAFE spent 10 years on development and continuous improvement and, drawing on practical applications and on-site testing at a number of airports, launched its unique potted primary cable connector.

The connector uses internal potting and an assembled connection design; the encapsulant fully fills the internal gaps, binding the core, insulation layer and sealing elements tightly together to form a stable insulating and waterproof barrier. The connector and cable become one, with no need for traditional heat-shrink joints, effectively reducing insulation risks caused by heat-shrink workmanship, moisture, freeze-thaw and bending. Standardised assembly also simplifies on-site work, reduces differences in manual operation and improves connection consistency and long-term reliability, providing more stable and lasting insulation protection for the lighting circuit.

04  Three-Layer Composite Structure · Coordinated Protection by Multiple Media

Structural innovation
A three-layer composite protective structure — outer protection + middle buffer + inner-core sealing — provides mechanical strength while also delivering flexible buffering and sealing insulation, enhancing the connection's ability to adapt to bending, compression and complex environments.

Material coordination
The combination of a rigid resin housing + a thermoplastic elastomer sleeve + high-insulation encapsulant exploits the performance advantages of different materials, improving overall waterproofing, insulation, impact resistance and deformation resistance.

Process improvement
An injection potting process allows the encapsulant to fully fill internal gaps, reducing air bubbles and local voids, improving potting uniformity and consistency, and further enhancing the connector's long-term insulation and sealing reliability.

05  Core Value of One-Shot Potting

More stable insulation — reduces the potential weak points introduced by traditional heat-shrink connection steps.
More reliable waterproofing — encapsulant filling + male/female sealing + tail locking form a complete waterproof path.
More stable structure — the rigid resin outer layer reduces the risk of structural deformation under compression and bending.
More efficient installation — assembled connection, no additional heat source required, and no need to wrap 3M tape around the joint.

06  Continuous Tracking · Long-Term Verification

In 2023, Chengdu Shuangliu International Airport used new cable + AIRSAFE primary cable connectors + AIRSAFE isolation transformers to retrofit four key circuits and carried out continuous tracking tests. Operating data showed that after the retrofit the circuit insulation resistance remained at a high GΩ level over the long term, with stable overall performance and no obvious degradation, verifying the long-term reliability of the AIRSAFE potted primary cable connector in real airport operating conditions.

The stable measured performance won the airport's continued trust, and subsequent related circuit retrofits also continued to use AIRSAFE potted primary cable connectors.

Selected Airport Applications

Chengdu Shuangliu International Airport、Wuhan Tianhe International Airport、Yinchuan Hedong International Airport、Shenzhen Bao'an International Airport
and a number of trunk and regional airport projects

07  Two Implementation Paths: New Airport / Existing Circuit Retrofit

The cable condition and the overall matching of the primary cable connector and the isolation transformer should be considered as a whole, and different implementation schemes adopted for new airport and retrofit project scenarios, so as to achieve a higher and more stable circuit insulation level.

08  Installation Precautions

The product's structural design is only the basis for safeguarding insulation performance; standardised installation is equally decisive for the final result.

Installation temperature, moisture control, cable condition, cleanliness of the bonding surface and glue storage conditions all directly affect potting quality and the circuit insulation level. Strict adherence to the installation specification is therefore essential to ensure that the product's designed performance truly translates into long-term, stable operating results.

· Avoid working at low temperatures: work is not recommended below 5°C and is strictly prohibited below 0°C; low temperatures extend the glue curing time, and heating measures must be taken in emergencies such as rush repairs.

· Never work in the rain: avoid water entering the cable and the bonding area of the connector, which would affect the final insulation performance.

· Never use water-soaked cable: damp cable or cable with water ingress significantly reduces the insulation level.

· Keep the bonding surface clean: do not touch the bonding area with bare hands, to prevent sweat, grease and impurities from affecting the bonding result.

· Avoid direct sunlight on the glue: exposure to direct sunlight is strictly prohibited, to prevent the glue from caking, losing flowability or even becoming unusable.

· Store properly: glue should be kept in an indoor constant-temperature environment at 5°C–30°C, protected from compression and impact.