The CTHW8 Outdoor waterproof current transformer features a split-core circular design, allowing it to be clamped directly onto live power cables without the need for system shutdowns or the disconnection of cables and terminals. Its smooth inner aperture conforms to the cable's shape, while a screw-and-pin locking mechanism ensures a secure, shift-free fit. Combined with a high-precision iron core, it delivers stable current acquisition.
The split-core circular design ensures a tight fit between the inner aperture and the cable's outer surface, accommodating single-core and multi-core low-voltage power cables of various diameters. Compared to square-aperture transformers, this design offers a tighter fit with no wobbling, resulting in more stable measurement accuracy. The split structure eliminates the traditional requirement to disconnect wires for installation, enabling retrofitting without power outages. A single person can install a unit in seconds, significantly shortening installation times and avoiding losses associated with production downtime.
The unit features a top-mounted knob-operated screw locking mechanism with an integrated positioning pin. Tightening the screw securely closes the upper and lower housings, ensuring the iron core mating surfaces meet without gaps. Simultaneously, the positioning pin presses against the cable's outer surface to lock the transformer in place, effectively preventing sliding or rotation. This ensures long-term stable operation—even in high-vibration environments—and structurally eliminates measurement errors caused by loosening.
It utilizes a high-quality grain-oriented silicon steel core characterized by high magnetic permeability, low magnetic loss, and excellent magnetization curve linearity. It delivers a stable output signal within the rated current range, meeting Class 0.5 or Class 1 metering accuracy standards and ensuring reliable, accurate current data acquisition. The product supports dual-frequency operation (50Hz/60Hz) and offers strong resistance to external electromagnetic interference, ensuring stable integration with various multifunction power meters, intelligent monitoring terminals, and relay protection devices.
This CTHW8 Outdoor waterproof current transformer features a unibody injection-molded housing made of high-strength, flame-retardant engineering plastic, offering excellent insulation, impact resistance, and durability against temperature extremes. The interior is vacuum-potted with epoxy resin, providing comprehensive protection against moisture, dust, and corrosion. It is suitable for diverse and demanding environments—such as industrial plants, outdoor distribution boxes, underground distribution shafts, and utility tunnels—maintaining consistent performance over the long term and ensuring an extended service life.
Transparent terminal cover: Wiring status is clearly visible, enhancing efficiency during on-site installation acceptance and subsequent troubleshooting or maintenance.
Clear polarity markings: P1/P2 directional indicators and secondary terminal polarity are marked on the housing surface to prevent wiring errors.
Waterproof cable exit: Comes with a specialized, bend-resistant output cable; the connection point features a waterproof seal to enhance the overall protection rating.
Integrated, accessory-free design: Ready to install right out of the box with no need for additional parts, reducing material costs.
Loosen the top locking screw by turning it counter-clockwise, then gently separate the upper and lower housing sections along the parting line.
Position the cable to be measured in the center of the transformer's aperture, ensuring it is coaxial with the opening and free from misalignment or compression.
Align the mating surfaces and close the housing sections; tighten the top locking screw clockwise to ensure a snug fit and that the locking pin firmly secures the cable.
Open the transparent terminal cover, connect the secondary leads correctly according to the polarity markings, and close the cover to complete the installation.
Never leave the secondary circuit open while the transformer is in operation; an open circuit can induce high voltages that endanger personnel and equipment safety.
Select a model with the appropriate aperture size based on the actual outer diameter of the cable to ensure a proper fit.
For installations in outdoor or high-humidity environments, it is recommended to apply additional waterproofing/sealing to the wiring connections. Application Scenarios
Retrofitting Existing Distribution Systems: Installing metering and monitoring devices on cable circuits in aging industrial parks or commercial buildings without the need for power outages or wire disconnection.
Building Power Distribution O&M: Monitoring current and analyzing energy consumption statistics for cable circuits located in electrical risers and utility shafts.
Industrial Power Monitoring: Real-time monitoring of operating currents for cable-powered equipment such as production lines, pumps, fans, and air compressors.
Smart Power Distribution Systems: Integration with power monitoring platforms and energy management systems to enable remote data acquisition and fault early warning.
Earth Leakage Protection: Customizable as a zero-sequence current transformer for residual current monitoring and earth leakage protection within power distribution systems.
The entire product line is manufactured in strict accordance with national standards. Each CTHW8 Outdoor waterproof current transformer undergoes comprehensive testing—including accuracy calibration, power-frequency withstand voltage tests, and insulation performance checks—prior to shipment to ensure stable, reliable performance. A one-year warranty is provided.
Project Name: Suzhou Smart Lighting Energy Monitoring Retrofit Project | Location: Suzhou City, Jiangsu Province
Completion Date: September 2023
Product Used: φ45mm Insulation-Piercing Split-Core Current Transformer
The project covers a 6.2-kilometer stretch of a major urban arterial road featuring 218 street lighting distribution circuits. Each circuit utilizes 3×16mm² power cables to supply LED streetlights and landscape lighting. Originally constructed in 2015, the existing distribution system offered only basic main-switch on/off functionality, lacking capabilities for individual circuit current monitoring or energy consumption statistics.
As requirements for refined municipal lighting management increased, local authorities planned to install energy monitoring and fault early warning systems across the entire lighting network. However, they faced challenges such as difficulties in obtaining approval for power outages on major roads, high wiring costs due to the dispersed nature of outdoor installation points, and the need to cut cables for traditional current transformer retrofits. Ultimately, the project selected insulation-piercing split-core current transformers as the core components for current acquisition, allowing the entire retrofit to be completed without any power outages.
Lack of branch-circuit current monitoring; extremely low troubleshooting efficiency. There was no per-circuit current data collection across the lighting network; identifying damaged streetlights or line faults relied solely on manual night patrols. The average time to detect a fault exceeded 12 hours, with issues in remote sections sometimes persisting for 2–3 days before resolution. Consequently, the road lighting availability rate hovered around 92%, failing to meet required standards.
Crude energy management; inability to detect anomalous power usage. Only the master meter measured total consumption, making it impossible to distinguish energy usage by individual circuit. Issues such as line leakage or unauthorized power tapping by nearby businesses went undetected, resulting in estimated annual non-lighting energy losses exceeding 50,000 RMB.
Traditional retrofitting required power outages, causing significant public impact. Using standard through-hole current transformers would have required cutting cables and shutting off power. Outages on main roads would have disrupted traffic signals, street lighting, and power supplies to nearby shops. Furthermore, the approval process for outages was complex, and nighttime installation posed high safety risks.
Widely dispersed outdoor locations; high costs for power supply wiring. The 218 monitoring points were scattered along the road. Installing separate power cables for each data collection module would have incurred combined material and labor costs exceeding 120,000 RMB; additionally, outdoor wiring is prone to aging and high failure rates.
To address the core requirements of dispersed outdoor locations and zero-outage installation, the project exclusively utilizes insulation-piercing, split-core current transformers. These integrated units handle both current measurement and self-powered operation for the circuit, eliminating the need for additional power supply lines.
Core Design Principles
Insulation-piercing, self-powered solution: The transformer utilizes built-in piercing electrodes to penetrate the streetlight phase wire's insulation and draw operating power. This simultaneously powers the current collection and communication modules, removing the need for independent power supply lines.
Split-core, no-disconnect installation: Featuring a snap-on, split-core structure, the device clamps directly onto the cable exterior. This eliminates the need to cut cables or disconnect terminals, allowing for live installation in low-voltage environments. High-protection outdoor design: The unit achieves an IP65 dustproof and waterproof rating and features a waterproof sealing ring at the piercing point, making it suitable for outdoor environments exposed to rain, intense heat, and freezing winter temperatures.
Zero-outage installation; no disruption to normal urban operations: Work was performed by certified low-voltage electricians following standard live-working procedures. No power outages were implemented on main roads, and neither traffic lighting nor the power supply to nearby businesses was affected. A total of 218 units were installed and commissioned in just seven days—reducing the project timeline by over 60% compared to traditional retrofit methods.
No additional wiring required; significant reduction in retrofit costs: Leveraging piercing-based self-powering technology eliminated the need to lay power cables for individual units. This saved approximately 85 RMB in material and labor costs per unit, resulting in total wiring cost savings of over 180,000 RMB and a 40% reduction in overall retrofit costs.
Reliable piercing seal; safe for long-term outdoor operation: The piercing electrode is made of tinned copper, ensuring uniform piercing force without damaging the conductor core. A silicone rubber waterproof seal ensures complete isolation from rain and moisture once locked. Since deployment, the units have withstood Suzhou’s rainy season, summer highs of 40°C, and winter lows of -5°C without experiencing insulation degradation, water ingress, or short circuits.
Stable measurement accuracy; meets energy consumption metering requirements: The mating surfaces of the split-core sensor undergo precision grinding, resulting in minimal magnetic circuit loss upon closure and achieving Class 0.5 accuracy—meeting requirements for sub-metered energy statistics. High sensitivity to low-current signals allows for the precise detection of current changes caused by individual streetlamp failures, enabling accurate early warning of faults.
Convenient and efficient installation; suitable for outdoor work environments: The lightweight units feature integrated locking clips, allowing a single technician to complete aerial installations without heavy tools. This significantly reduces both the safety risks and the difficulty associated with working at heights outdoors.
Significantly improved O&M efficiency and compliant lighting rates: The system monitors current in real-time across all circuits, automatically pushing alerts within 10 minutes for open circuits, short circuits, or abnormal outages, thereby reducing the average fault resolution time by 80%. The road lighting rate rose from 92% to 99.2%, meeting the Grade I standard for municipal lighting.
Refined energy management and reduced losses: Post-implementation analysis of energy data identified three points of unauthorized power tapping and two instances of hidden line leakage. Remediation reduced abnormal monthly energy loss by approximately 2,300 kWh, resulting in annual electricity cost savings exceeding 25,000 RMB.
Stable equipment operation with zero faults: As of October 2024, all 218 current transformers have operated continuously and stably, showing no water damage, accuracy drift, or overheating at connection points; the equipment integrity rate stands at 100%.
Successful municipal acceptance: The project complies with the Technical Specification for Construction and Acceptance of Urban Road Lighting Engineering (CJJ 89) and relevant national standards for current transformers, passing the municipal authority's special acceptance inspection for smart lighting retrofitting on the first attempt.
The split-core current transformer with insulation-piercing technology is a core innovative component for the smart retrofitting of distributed outdoor power distribution systems. It effectively resolves three major industry pain points associated with traditional retrofitting methods: the difficulty of scheduling power outages, high wiring costs, and slow installation speeds.
This technology is widely applicable to scenarios characterized by dispersed locations and challenging power access, such as municipal streetlights, outdoor EV charging piles, industrial park power distribution, and rural power grids. It enables the rapid deployment of current monitoring and energy data collection systems with zero power outages, minimal wiring, and low costs, making it a highly cost-effective sensing-layer solution for the Internet of Things (IoT) in power distribution and smart city construction.
Address
No. 318, Weidian Road, Economic Development Zone, Yueqing City, Zhejiang Province, China
Tel
