Industrial-Grade Rectangular Current Transformer: High-Precision Reliable Solutions for Professional Current Sensing Application

Introducing the Rectangular Residual Current Transformer (RCT) from YAONAN—a trusted manufacturer specializing in low-voltage electrical protection components—this device emerges as a safety-critical pillar engineered for modern electrical distribution and control systems.

Encased in a robust, flame-retardant red insulated housing (forged from high-grade polyamide material that adheres to IEC 60695 flame-resistance standards), the unit features a purpose-built rectangular open-core design: this generously sized rectangular aperture is specifically optimized to accommodate multiple cable strands, thick busbars, or bundled power conductors, eliminating the need for tedious disassembly during on-site wiring and drastically streamlining installation workflows for electricians. On the lower right flank of the enclosure, a pair of green-colored terminal blocks (constructed from nickel-plated copper to boost electrical conductivity, resist corrosion, and ensure long-term connection stability) are seamlessly integrated; each terminal is fitted with a slotted screw, enabling secure, tool-friendly termination of secondary-side signal wires—guaranteeing consistent, uninterrupted signal transmission between the RCT and downstream leakage protection devices (LPDs). For hassle-free integration into diverse electrical infrastructure, the device includes a precision-drilled mounting hole on its base, supporting both wall-mount and panel-embedded installation (compatible with standard DIN rail accessories or direct bolt fastening, depending on the specific application environment).

Functionally, this rectangular RCT operates on the foundational principle of Kirchhoff’s Current Law: under normal circuit conditions, the vector sum of currents entering and exiting a closed loop equals zero. In practice, when electrical current flows through the primary conductor (threaded through the RCT’s rectangular core), the magnetic fluxes generated by the incoming and outgoing currents cancel each other out, leaving the transformer’s secondary winding with no induced voltage output. However, if a residual (leakage) current arises—whether from insulation degradation, accidental human contact with live components, or equipment malfunction—the current balance is disrupted: the uncompensated leakage current generates a net magnetic flux within the core, inducing a proportional electrical signal in the secondary winding. This signal is then relayed to a connected leakage protection relay or circuit breaker, which triggers a rapid tripping action (typically within milliseconds) to isolate the faulty circuit, thereby mitigating risks of electric shock, equipment damage, or electrical fires stemming from uncontrolled current leakage.

Designed for seamless compatibility with low-voltage electrical systems (rated for AC 50/60Hz, 0.4kV distribution networks), this RCT boasts broad applicability across scenarios: it is commonly deployed in residential building distribution boards, industrial plant motor control centers (MCCs), commercial facility power distribution units (PDUs), photovoltaic (PV) inverter DC/AC distribution loops, elevator and water pump electrical control circuits, and critical equipment power supplies in healthcare facilities. It adapts to a wide range of primary current ratings (spanning 50A to 630A across different model variants), making it suitable for both light-duty residential loads and heavy-duty industrial machinery circuits.

Beyond its core safety functionality, this YAONAN rectangular RCT offers notable performance advantages: it delivers high-precision residual current detection (with a typical accuracy class of 0.5 or 1.0, ensuring reliable signal output for protection devices), incorporates a low-power secondary circuit design to minimize energy consumption, supports a wide operating temperature range (-25°C to +70°C) for use in harsh environmental conditions, and integrates electromagnetic shielding materials in its housing to resist interference from adjacent electrical components—preserving signal integrity even in high-noise electrical environments. Compliant with international standards such as IEC 61869-10 (the global benchmark for residual current transformers) and certified for long-term durability (with an expected operational lifespan of over 10 years under normal conditions), this device requires minimal maintenance, reducing long-term operational costs for end-users.