Addressing the pain points associated with traditional closed-core transformers—which require power outages, busbar disassembly, high installation costs, and production disruptions—this outdoor waterproof model features a split-core, open-close design. It can be clamped directly onto cables or busbars without cutting power or altering wiring, significantly shortening installation time and minimizing losses caused by downtime.
1. Snap-on Open-Close Structure
CTHW6 Outdoor waterproof current transformer eliminates the need to cut power or disconnect wires during installation. By simply loosening the side locking screw, the housing opens to clamp directly onto the target cable or busbar; closing and locking it completes the installation. The entire process requires no power interruption, takes less than one minute per unit, and boosts installation efficiency by over 80%, making it ideal for retrofitting existing distribution systems while avoiding production losses.
2. High-Precision Core
It features a high-quality grain-oriented silicon steel core offering high magnetic permeability, low magnetic loss, and a wide linear range. It delivers stable output signals within the rated current range, meeting Class 0.5/0.5S metering accuracy standards. It ensures precise, reliable current data acquisition and strong electromagnetic interference resistance, making it compatible with various power meters, smart monitoring terminals, and protection devices.
3. Flame-Retardant, Insulated Encapsulation
The housing is injection-molded from high-strength, flame-retardant engineering plastic, offering excellent temperature resistance, impact resistance, and insulation properties. Internally, it utilizes vacuum-poured epoxy resin encapsulation to provide moisture, dust, and corrosion resistance. This allows for stable long-term performance and an extended service life in demanding environments, such as industrial plants, outdoor distribution boxes, and underground distribution rooms.
4. User-Friendly Design Details
Transparent terminal cover: Wiring status is clearly visible, facilitating easier inspection and acceptance.
Clear polarity markings: P1/P2 and secondary terminal polarities are clearly labeled to prevent wiring errors.
Waterproof locking connector: Equipped with a waterproof cable gland at the output point to enhance the overall protection rating.
Metal locking mechanism: Secure screw locking and a tight housing fit (zero-gap closure) ensure measurement accuracy.
1. Loosen the locking screw on the side of the unit and open the upper and lower housing halves along the hinge.
2. Place the cable or busbar to be measured in the center of the transformer's aperture, ensuring the conductor is centered.
3. Align the mating surfaces, close the housing halves, and tighten the locking screw until the fit is snug and gap-free.
4. 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 circuit open during operation; doing so can generate high voltage, endangering personnel and equipment safety.
Before installation, verify that the current ratio matches system requirements and that the conductor specifications are compatible with the aperture size.
For outdoor or humid environments, apply additional waterproofing/sealing treatment to the wiring terminals.
Retrofitting existing power distribution: Smart upgrades for aging distribution cabinets and boxes; adding energy monitoring devices without requiring a total plant shutdown.
Industrial energy management: Current monitoring and energy consumption analysis for factory production lines and power equipment circuits.
Smart power distribution monitoring: Works with multifunction power meters and distribution monitoring systems to enable real-time current data acquisition and remote monitoring.
Building power distribution: Operations, maintenance, and fault warning for power distribution in commercial complexes, office buildings, hospitals, and data centers.
New energy power distribution: Current monitoring and protection for circuits in PV grid-tie cabinets, energy storage systems, and EV charging piles.
All CTHW6 Outdoor waterproof current transformers are manufactured in strict accordance with relevant national standards. Each unit undergoes multiple factory tests—including accuracy calibration, power-frequency withstand voltage testing, and insulation performance checks—to ensure stable and reliable performance. Supports customization of non-standard specifications to meet diverse installation dimensions and parameter requirements.
A professional technical team provides model selection guidance and after-sales technical support.
Products come with a one-year warranty.
Project Name: Electrical Fire Monitoring System Retrofit for a Precision Hardware & Injection Molding Factory in Chang'an Town, Dongguan City
Location: Hardware and Mold Industrial Park, Chang'an Town, Dongguan City, Guangdong Province
Retrofit Date: March 2025
Products Used: Full range of split-core (openable) residual current transformers
The factory was built in 2011 with a total floor area of approximately 28,000 m². It houses three major production workshops—injection molding, stamping, and mold processing—and operates 86 low-voltage distribution circuits. Loads include injection molding machines, CNC stamping machines, chiller units, overhead cranes, and lighting/power sockets. Due to lower standards at the time of initial construction, only the main incoming power cabinet was equipped with a residual current circuit breaker (RCCB); branch circuits lacked any residual current monitoring capabilities.
In the second half of 2024, the local Emergency Management Bureau launched a special campaign to improve electrical safety in industrial and trade enterprises, mandating the installation of an electrical fire monitoring system within a specified timeframe. Additionally, the facility experienced frequent, unexplained residual current trips of the main breaker during the rainy season; troubleshooting a single fault required halting production across the entire line for over three hours, severely impacting order fulfillment. Furthermore, wiring insulation was aging rapidly due to the high-temperature, oily environment of the injection molding workshop, leading to safety hazards where operators felt electric shocks upon touching equipment casings. Consequently, a system retrofit became urgently necessary.
Traditional retrofitting methods require production shutdowns, resulting in massive economic losses. Using conventional solid-core (pass-through) residual current transformers would necessitate dismantling busbars and cutting cables. A single day of downtime for one production line would incur direct losses exceeding 120,000 RMB, and a plant-wide retrofit was estimated to require three days of downtime—an option the factory could not accept. Lack of tiered leakage monitoring results in extremely low troubleshooting efficiency. Only the main breaker has a leakage-trip function; branch circuit leakage cannot be pinpointed. Electricians must test circuits one by one after every trip, resulting in an average troubleshooting time of 3.5 hours and a monthly production capacity loss of approximately 8% due to leakage-related outages.
Harsh industrial environments exacerbate leakage risks. Injection molding workshops feature high temperatures and heavy oil contamination, accelerating cable insulation aging; stamping workshops experience intense vibration, causing terminals to loosen and creating high risks of hidden leakage—conditions that exceed the durability limits of traditional devices.
Mandatory compliance requirements: Failure to meet the GB 14287.2-2014 standard ("Residual Current Electrical Fire Monitoring Detectors") classifies the facility as requiring rectification under industrial safety mandates, with penalties including production suspension for non-compliance by the deadline.
To meet the core requirement of "retrofit without production stoppage," the project exclusively utilizes split-core residual current transformers. Models are selected based on circuit conductor type and cross-sectional dimensions, allowing for installation without disconnecting wires or cutting power.
Installation without power interruption; zero production loss. The split-core design features a snap-fit mechanism with locking screws, eliminating the need to disassemble busbars or cut cables; certified electricians perform the installation on live circuits in accordance with safety standards. All production lines operated normally throughout the retrofit, resulting in no order delays or capacity losses—saving the factory an estimated 300,000+ RMB in potential downtime costs.
High connection precision and stable, reliable measurement performance. The mating surfaces of the magnetic core undergo precision grinding, ensuring low magnetic reluctance and high consistency upon closure, with a residual current measurement error of ≤1%. The system accurately detects leakage signals as low as 50mA; post-commissioning data shows a false alarm rate of less than 2%, fully meeting precision requirements for electrical fire early warning systems. Highly adaptable for both copper busbars and power cables; square-hole models fit rectangular busbars, while round-hole models fit circular power cables, covering the full range of circuits from branch lines to main feeders. Unified model selection and supply for the entire project eliminate the need for custom mold creation, resulting in short lead times and standardized installation.
Oil and high-temperature resistant, suitable for harsh industrial conditions; the housing is made of flame-retardant, reinforced engineering plastic with excellent sealing properties, effectively blocking workshop oil, moisture, and dust. With an operating temperature range of -25°C to +85°C, it withstands the high-temperature environments surrounding injection molding machines, ensuring long-term operation without insulation aging or accuracy drift.
60% increase in installation efficiency, significantly shortening the project timeline; installation and wiring for a single transformer take an average of only 10 minutes. The installation and commissioning of all 86 units across the plant were completed in just 5 days—far below the estimated 15-day timeline for traditional through-hole transformer retrofits—meeting rectification requirements ahead of schedule.
Successfully passed the special safety inspection; in April 2025, the system passed the electrical safety inspection conducted by the Dongguan Emergency Management Bureau. Residual current monitoring, alarm logic, and graded protection functions all comply with the GB 14287.2 national standard, fully resolving compliance issues.
90% improvement in troubleshooting efficiency; the system precisely identifies the circuit ID where leakage occurs and issues real-time alarms. Troubleshooting time dropped from an average of 3.5 hours to under 20 minutes, drastically reducing the impact of power-off inspections on production.
Proactive hazard warnings eliminate accident risks; as of October 2025, the system had issued 11 warnings regarding residual current anomalies (7 due to motor insulation aging and 4 due to terminal oxidation/moisture). Rectifications were completed before any tripping occurred, preventing unplanned power outages, equipment burnout, or electric shock incidents.
Zero-fault equipment operation; despite the harsh workshop environment characterized by high temperatures, oil, and vibration, all split-core transformers operated stably with no cracking, corrosion, or accuracy drift, maintaining a 100% equipment integrity rate.
Split-core residual current transformers are the preferred core components for retrofitting aging power distribution systems to prevent electrical fires. They effectively resolve the major pain points associated with traditional fixed-type transformers—namely, the need for power outages and wire disconnection, lengthy installation periods, and disruptions to production and business operations.
They are particularly well-suited for environments where power supply continuity is critical, such as industrial plants, commercial complexes, data centers, and hospitals. These transformers enable compliant upgrades to residual current monitoring systems with zero production downtime and minimal structural modification, balancing safety compliance, operational stability, and cost-effectiveness. They represent a highly cost-efficient solution for upgrading the electrical safety of existing power distribution systems.
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