Our CTHW9 Outdoor waterproof current transformers feature a symmetrical dual-screw locking mechanism. Compared to single-screw designs, this structure ensures more uniform force distribution and a tighter core closure, structurally guaranteeing measurement accuracy and long-term operational stability. The product line offers various aperture sizes to accommodate low-voltage power cables of different diameters.
Utilizing a symmetrical dual-screw locking mechanism, the screws on both sides are tightened alternately during installation. This ensures uniform force distribution across the upper and lower transformer housings and a tight, gap-free fit at the core interface, eliminating issues like misalignment or accuracy deviations caused by single-sided locking. The locking pins press firmly against the cable's outer surface, preventing slippage or rotation and ensuring stable measurement performance over the long term, even in high-vibration environments such as those involving motors or fans.
Models are available with various internal aperture sizes, fully covering low-voltage power cables ranging from small to large cross-sections. They are compatible with both single-core and multi-core cables, meeting data acquisition needs for circuits with capacities from 5A to 4000A. Selection is flexible, allowing for precise matching with circuit currents and cable specifications; no cable modification is required, as the units can be installed directly via a simple clamp-on mechanism.
Equipped with a high-quality grain-oriented silicon steel core, the device offers high magnetic permeability, low magnetic loss, a wide linear range, and strong resistance to electromagnetic interference. It can function as a metering-grade current transformer—achieving Class 0.5 or Class 1 accuracy for operating current acquisition when paired with power meters and energy monitoring systems—or be customized as a zero-sequence current transformer to precisely detect residual currents at the milliampere level for use with earth leakage protection and fire safety power monitoring devices.
The housing is molded from high-strength, flame-retardant engineering plastic, offering resistance to impact and aging caused by temperature extremes. The interior utilizes a vacuum epoxy resin potting process, providing comprehensive protection against moisture, dust, and corrosion, achieving an IP65 protection rating. CTHW9 Outdoor waterproof current transformer ensures stable, long-term operation and extended service life in diverse environments—from industrial plants and outdoor distribution boxes to underground utility tunnels and humid electrical shafts.
Transparent terminal cover: Wiring status is clearly visible; covers do not need to be removed for on-site acceptance or routine inspections, making troubleshooting more efficient.
Clear polarity markings: P1/P2 direction and secondary terminal polarity are marked on the housing surface to effectively prevent wiring errors.
Waterproof, bend-resistant cable exit: Comes with a dedicated output cable featuring a sealed, waterproof interface, suitable for outdoor installation requirements.
Integrated design (no extra accessories needed): Ready to install right out of the box without purchasing additional parts, reducing overall installation costs.
Alternately loosen the locking screws on both sides (counter-clockwise) and gently separate the upper and lower housing halves along the parting line.
Position the cable to be measured in the center of the transformer's inner aperture, ensuring it is centered and does not press against the inner walls.
Align the mating surfaces and close the upper and lower housing halves; alternately tighten the screws on both sides (clockwise) to ensure the surfaces fit perfectly and the internal contact pin firmly secures the cable.
Open the transparent terminal cover, connect the secondary side wiring correctly according to the polarity markings, and close the cover to complete the installation.
Never leave the secondary side of the current transformer open-circuited during operation, as induced high voltage poses a risk to personnel and equipment safety. When installing a zero-sequence transformer, ensure that both the phase line(s) and the neutral line pass through the transformer in the same direction, and pay attention to polarity matching during wiring.
Select the appropriate inner aperture size based on the cable's actual outer diameter; for outdoor environments with high humidity, additional waterproofing treatment for the wiring connection area is recommended.
Retrofitting Existing Distribution Systems: Installing metering and monitoring on cable circuits in older industrial zones and commercial buildings without the need for power outages or wire disconnection, ensuring zero production downtime.
Industrial Energy Management: Collecting current data from circuits powering production lines, utility equipment, air compressors, etc., to enable energy consumption statistics and efficiency analysis.
Residual Current Protection: Acting as a zero-sequence current transformer paired with leakage protection devices to ensure electrical safety within the distribution system.
Fire Safety Power Monitoring: Monitoring current and residual current in fire-safety power distribution circuits to comply with fire safety system regulations.
Smart Power Distribution Monitoring: Integrating with power monitoring platforms and IoT terminals to enable remote data acquisition and fault early warning.
Our full range of CTHW9 Outdoor waterproof current transformers is manufactured in strict accordance with national standards. Each unit undergoes comprehensive testing—including accuracy calibration, power-frequency withstand voltage tests, and insulation performance checks—before leaving the factory to ensure stable and reliable performance.
Customization available: Current ratios, aperture sizes, output configurations, and zero-sequence parameters can be adjusted to meet specific requirements.
Professional technical team provides selection guidance and end-to-end after-sales technical support.
Products come with a 1-year warranty; purchase with confidence knowing quality is guaranteed.
Project Name: Energy Consumption Monitoring System Retrofit for a Smart Logistics Park in Xiaoshan District, Hangzhou.
Location: Chuanhua Logistics Base, Xiaoshan District, Hangzhou City, Zhejiang Province.
Completion Date: March 2026.
Products Used: Various specifications of insulation-piercing, split-core current transformers.
The logistics park was completed and put into operation in 2018, featuring a total building area of 120,000 m². It comprises three high-standard warehouses, an automated sorting center, a low-temperature cold chain storage area, and supporting office facilities. The park operates 172 low-voltage distribution circuits, with annual electricity costs exceeding 3.2 million RMB. The original distribution system was equipped only with a main incoming meter and lacked sub-metering capabilities for energy consumption. Furthermore, due to the specific operational requirements of the cold chain and sorting businesses, the facility could not accommodate the prolonged power outages typically required for such retrofits. To meet requirements for industrial energy conservation and cost reduction, and to achieve zoned electricity cost accounting and anomaly alerts, the park initiated an intelligent power distribution upgrade. Split-core current transformers (CTs) featuring insulation-piercing power tapping were selected as the core current-sensing components, enabling the deployment of monitoring across all circuits without any power outages.
Lack of sub-metered energy consumption data and coarse cost control: Relying solely on a master meter made it impossible to disaggregate electricity costs across warehousing, sorting, cold chain, and office zones. It also prevented the identification of hidden waste—such as equipment idling or running without load—leaving electricity costs high and unoptimized, while energy-saving upgrades lacked data-driven justification.
Prohibitive costs and infeasibility of outage-based upgrades: A power outage exceeding four hours in the cold chain storage area could damage fresh produce, with estimated losses exceeding 200,000 RMB per incident. The sorting center generates over 800,000 RMB in daily output during peak seasons, making a single day of downtime extremely costly. Traditional "through-hole" CTs required cutting cables for installation; since outage approvals could not be secured, the upgrade plan was initially shelved.
Cramped installation space within cable trays and wiring difficulties: Over 80% of power circuits were concentrated within cable trays. Traditional upgrades would have required extensive removal of tray covers and the laying of additional power cables, resulting in a massive workload, high safety risks, and potential disruption of existing cable layouts.
Absence of real-time current monitoring and difficulty detecting overload risks: Sorting equipment loads fluctuate significantly during major e-commerce sales events. Prolonged line overloads can accelerate insulation aging or even cause fires. Limited manual inspection frequency meant hidden faults often went undetected; incidents had previously occurred where branch circuit overheating caused tripping and interrupted sorting operations.
Addressing the core requirements of "zero power outages, minimal wiring, and suitability for cramped spaces," the project utilized split-core CTs with insulation-piercing power tapping across all circuits, with models selected based on specific circuit specifications.
Core Design Principles
Insulation-piercing self-powering: Utilizing built-in piercing electrodes, the CTs draw power directly through the insulation of the phase conductor to supply the sensing and communication modules, eliminating the need to lay 220V power cables for any of the monitoring points. Hinged, Non-Severing Design: Features a snap-lock hinged structure that clamps directly onto the cable exterior; eliminates the need to cut cables or disconnect terminals, allowing for installation without power interruption in compliance with low-voltage live-working standards.
Sub-metering Architecture: Collects data by functional zone and power usage type, uploading it to a centralized energy management platform to enable zonal electricity cost accounting, abnormal usage alerts, and energy consumption trend analysis.
Compact Space Adaptability: Optimized device dimensions and reduced operational clearance requirements make it suitable for tight installation environments, such as cable trays and areas with dense wiring.
Zero-Downtime Installation & Zero Operational Loss: Certified low-voltage electricians performed live-line work strictly according to regulations. The retrofit process caused no interruptions to the power supply for cold-chain refrigeration and sorting systems, resulting in no cargo damage or order delays. This alone avoided estimated power-outage losses exceeding 500,000 RMB and eliminated complex outage approval and load-transfer procedures.
Elimination of Power Cabling & 35% Reduction in Total Cost: Leveraging self-powered insulation-piercing technology, there was no need to lay separate power lines for the 172 monitoring points. This reduced costs associated with cabling materials, cable tray drilling, and labor; the overall retrofit cost was approximately 35% lower than traditional solutions, and the construction period was cut by more than half.
Adaptability to Tight Cable Tray Spaces & Significantly Improved Efficiency: The compact device requires minimal space for operation and installation, eliminating the need to remove large sections of cable tray covers. The entire process—clamping, piercing, and locking—can be completed with one hand, with an average installation time of just 8 minutes per unit. Rapid installation is possible even for circuits with dense wiring inside trays, significantly reducing safety risks associated with working at heights and in confined spaces.
Reliable Piercing Contact & No Overheating/Insulation Risks: Piercing electrodes are made of highly conductive tinned copper and feature a constant-force locking mechanism to ensure stable contact resistance. The piercing point includes an integrated insulation gasket, ensuring long-term indoor operation without overheating, oxidation, or insulation degradation; upon completion, the project passed a 72-hour full-load temperature rise test, with all points meeting national standards. Measurement accuracy meets standards and internal accounting requirements. The mating surfaces of the split-core sensors utilize precision grinding, ensuring a tight magnetic circuit closure and minimal magnetic loss, with measurement accuracy consistently within Class 0.5. The discrepancy between the aggregated sub-metering data and the master meter is less than 2%, fully satisfying management needs for internal energy consumption accounting and departmental cost allocation.
Implementation of sub-metered energy accounting; annual electricity savings exceed 200,000 RMB. The retrofit enabled refined electricity usage statistics categorized by zone and function. Data analysis identified waste points—such as high no-load energy consumption in the cold chain storage area at night and air compressors idling in the sorting area. After optimizing operational strategies, monthly electricity savings reached approximately 18,000 kWh, with projected annual electricity cost savings exceeding 200,000 RMB.
Proactive overload warnings prevent downtime incidents. The system established current overload warning thresholds. During the "618" and "Double 11" peak sorting seasons, heavy-load warnings were triggered three times. Operations and maintenance (O&M) personnel promptly adjusted equipment operating combinations and staggered the startup times of high-power equipment, preventing sorting interruptions caused by circuit overloads and trips; this avoided cumulative downtime losses exceeding 300,000 RMB.
Stable equipment operation with a 100% integrity rate. As of July 2026, all 172 current transformers have operated continuously and stably. No faults—such as overheating at the piercing point, insulation breakdown, or signal drift—have occurred. The equipment integrity rate is 100%, requiring no frequent maintenance or calibration, resulting in extremely low O&M costs.
Passed energy-saving acceptance and secured policy subsidies. The project met local application requirements for industrial energy-saving retrofit subsidies. Thanks to a comprehensive sub-metering system and clear energy-saving results, it successfully passed third-party acceptance and received a special energy-saving subsidy of 120,000 RMB, further reducing the retrofit cost.
Piercing-type, split-core current transformers offer a low-intrusion, low-cost, and highly efficient path for intelligent retrofitting in existing power distribution scenarios—such as logistics, industrial, and commercial facilities—where system shutdowns are unacceptable and modifications are difficult to implement. It resolves the installation challenges associated with traditional instrument transformers—which require power outages and wire disconnection—while eliminating the costs and time associated with additional power supply wiring. Capable of rapidly establishing systems for sub-metered energy consumption and condition monitoring, it serves as a highly cost-effective core sensing component that helps enterprises save energy, reduce costs, and upgrade their power distribution operations and maintenance.
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