Explore our top-tier catalog of certified RCCBs, MCBs, MCCBs, and specialized DC solar protection devices engineered for ultimate electrical safety.
Founded in 2013 and headquartered in Yueqing, Wenzhou—universally recognized as the Capital of Electrical Appliances in China—Wenzhou OFA Electrical Technology Co., Ltd. has established itself as an authoritative manufacturer and export supplier of low-voltage distribution switchgear, residual current operated circuit breakers (RCCBs), miniature circuit breakers (MCBs), and intelligent control equipment. Rooted in the world’s most dense electrical engineering cluster, OFA leverages localized supply chain integration, proprietary magnetic flux-sensing innovations, and high-throughput automated assembly to provide global energy systems with unparalleled electrical safety infrastructure.
Understanding the transition from passive electro-mechanical switching to smart, high-frequency responsive residual current sensing across global commercial, solar, and industrial networks.
The global residual current protection market is undergoing a seismic paradigm shift. Driven by the rapid proliferation of non-linear loads, high-power direct current (DC) solar photovoltaic (PV) arrays, battery energy storage systems (BESS), and electric vehicle supply equipment (EVSE), classical AC-only residual current devices (Type AC RCDs) are rapidly becoming obsolete in favor of advanced Type A, Type F, and Type B electromagnetic residual current circuit breakers (RCCBs and RCBOs).
At the technological heart of every high-quality RCCB manufactured by OFA lies a precision-engineered toroidal Zero-Sequence Current Transformer (ZSCT). Under balanced operating conditions, the vector sum of currents passing through the phase conductors and the neutral conductor equals zero ($\sum I = 0$). Consequently, the net magnetic flux generated inside the high-permeability nanocrystalline or permalloy toroidal core is absolute zero, keeping the secondary trip coil in a de-energized state.
When an insulation fault, accidental human contact, or ground leakage occurs downstream, a portion of the current escapes to the earth, disturbing the vector equilibrium ($\sum I = I_{\Delta n} \neq 0$). The residual magnetic flux induces an electromotive force (EMF) across the secondary winding. Once this induced signal exceeds the calibrated electromagnetic threshold, the polarized tripping relay (holding magnet mechanism) releases within milliseconds—mechanically unlatching the spring-loaded contact bridge and instantly interrupting the circuit power supply.
| RCD Type Classification | Detectable Residual Current Waveforms | Primary Application Scenarios | OFA Model Series Matching |
|---|---|---|---|
| Type AC | Sinusoidal Alternating Current (50/60Hz) only | Standard resistive residential circuits, general lighting | OFAP6-AC, OFL7 Series |
| Type A | Sinusoidal AC + Pulsating Direct Current with DC superposition up to 6mA | Single-phase inverters, induction hobs, washing machines, modern IT loads | OFDX Series, OFGX 2P63A |
| Type F | Type A characteristics + Composite high-frequency AC leakage (up to 1kHz) | Single-phase variable speed heat pumps, air conditioners, industrial washers | OFKL-80A Custom Engineering |
| Type B | Type F characteristics + Smooth pure direct current (DC) residual currents up to 2kHz | 3-Phase PV Inverters, EV Chargers (IEC 62955), Industrial Automation, Medical MRI | OFDX-B Series, Specialized Smart Breakers |
From micro-ampere residual leakage detection to thousand-ampere heavy industrial fault isolation, OFA manufactures complete low-voltage power distribution solutions.
Engineered for main distribution panels, OFA MCCBs (BA88 Electronic, DCM1, DCOF1, OFM1, OFA-M1 Series) deliver rated currents up to 1250A with short-circuit breaking capacities up to 100kA. Features dual-magnetic and electronic trip units for selective system coordination.
Designed for sub-distribution circuits. Includes OF6KA, OF10KA C65, OFAFT, OFD4Z7, OFDL, OFDP, OFDZ47, OFEU, OFKL, OFKL-NXB, OFL7, OFL8, OFNC, OFPF, and OFP Series (4.5kA to 10kA). Guarantees rapid thermal-magnetic tripping during overloads and dead short-circuits.
The OFW1 Intelligent Universal Circuit Breaker series serves as the brain of large industrial power plants and transformer sub-stations. Combines deep micro-processor intelligence, fieldbus communications (Modbus-RTU/Profibus), and modular auxiliary contacts.
Dedicated high-sensitivity earth fault protection without integrated overcurrent protection. Product families include OFAP6-AC, OFDPN, OFDX, OFGX, OFID, OFL7, and OFPM. Tripping sensibilities range from 10mA (personal safety) to 300mA (fire protection).
Innovatively combines MCB overcurrent/short-circuit protection with RCCB leakage sensing in a single compact enclosure (1P+N or 3P+N). Series include OFC, OFKL-80A, NB1L, OFMIN, OFOM, and OFR1, optimizing panel DIN-rail space by up to 50%.
High-capacity main load disconnector switches including OFIS-125A, OFIS-BH, and OFIS-DS Series. Ensures positive contact isolation and safety interlocking during system maintenance and emergency power cut-off maneuvers.
From residential Smart Home consumer units to heavy industrial microgrids and renewable energy farms, OFA protection devices deliver targeted safety margins.
In modern residential installations, digital electronics, inverter-driven household appliances, and ambient LED dimming systems contaminate neutral conductors with high-frequency noise. Standard Type AC breakers often suffer from nuisance tripping or blind locking. Utilizing OFA’s OFDX Type A RCCBs and OFMIN Series RCBOs (30mA sensitivity), homeowners gain continuous shock protection without experiencing false tripping caused by lightning surge transients or capacitive switching currents.
Data centers operate with zero tolerance for un-planned downtime. Here, earth leakage protection must balance high sensitivity with extreme selectivity. OFA’s selective timed-delay RCCBs (Type S) installed at main distribution feeders provide upstream backup protection while allowing branch RCBOs (such as the OFKL-NXB Series) to clear localized ground faults instantaneously, keeping core server racks online uninterrupted.
Solar arrays and battery storage systems involve non-isolated DC voltage strings exceeding 1000V DC. Insulation breakdown between PV panels and mounting structures creates smooth DC fault currents. OFA’s specialized DCOF1-125/PV DC Miniature Circuit Breakers and Type B RCCB configurations eliminate core saturation risks, ensuring that residual DC current generated by transformerless string inverters triggers trip protection before thermal runaway or arc fires develop.
International EV charging standard IEC 61851-1 mandates explicit residual DC current protection of 6mA for all Mode 3 EV chargers. Combining an OFA Type A RCCB (OFDX Series) with an integrated 6mA DC residual direct detecting sensor provides EVSE manufacturers with a fully compliant, cost-optimized alternative to prohibitive full Type B protection units.
How OFA is integrating Artificial Intelligence, IoT connectivity, Arc Fault Detection (AFDD), and Solid-State Switching into modern breaker platforms.
Integrating real-time RS485 Modbus and wireless NB-IoT communication protocols into miniature breakers. Enables facility managers to remotely monitor operating temperatures, real-time ground leakage currents ($\mu A$), voltage sags, and execute predictive maintenance routines prior to tripping.
Merging high-frequency digital signal processing (DSP) algorithms with standard residual current mechanisms. Analyzes micro-second voltage waveform distortions to identify dangerous series and parallel arcing conditions responsible for electrical building fires.
Transitioning from traditional mechanical contact opening (which takes 5ms to 10ms) to Silicon Carbide (SiC) semiconductor switching. Achieves sub-microsecond trip speeds (less than 100 microseconds), eliminating electrical contact arcing entirely.
Capitalizing on the world's most complete low-voltage electrical ecosystem to deliver high precision, unmatched lead times, and cost-effective scalability.
Located in Yueqing, Wenzhou—the undisputed Capital of Electrical Appliances in China—Wenzhou OFA Electrical Technology Co., Ltd. enjoys unparalleled supply chain efficiency. Within a 15-kilometer manufacturing radius, OFA accesses specialized raw material suppliers for high-silver-content contact rivets ($AgNi10, AgSnO_2$), specialized bimetallic strips for precise thermal overload calibration, flame-retardant thermoplastics (PA66 with UL94 V-0 ratings), and magnetic alloy toroidal cores.
OFA believes that product quality stems from institutional integrity. Operating with strict corporate governance, OFA has been officially rated as Tax Credit Grade A for seven consecutive years in China. This financial health guarantees supply chain stability, continuous capital investment into mold tooling R&D, and seamless long-term warranty fulfillment for global partners.
From initial electrical boundary specification matching to mold development, type testing verification, and agile volume manufacturing.
OFA technical engineers analyze single-line electrical diagrams, operational ambient temperatures, breaking capacity (Icu/Ics) demands, and terminal terminal screw torque specifications to match or design target solutions.
Custom breaker housing molds, calibrated tripping springs, and contact bridges undergo full laboratory verification—ensuring compliance with CE, IEC 60947-2, IEC 61008-1, and UL standard requirements.
Upon client sign-off, flexible automated assembly lines initiate volume production. Products feature custom silk-screen branding, laser marking, secure export packaging, and traceable batch tracking codes.
See why system integrators, plant engineers, and electrical distributors across 50+ countries trust OFA for critical circuit protection.
In-depth technical answers addressing breaker selection, compliance, supply chain logistics, and OEM customization options.
An RCCB (Residual Current Operated Circuit Breaker) purely detects earth leakage currents (residual ground currents) and trips to prevent human shock or fire. It does NOT protect against overloads or dead short-circuits; thus, it must be paired in series with an MCB. An RCBO (Residual Current Breaker with Overcurrent Protection) innovatively integrates both RCCB residual current sensing and MCB thermal-magnetic overload/short-circuit protection into a single DIN-rail module.
Solar inverters and EV charging stations utilize DC-to-AC power electronics. A fault in these systems can inject smooth direct current (DC) ground leakage into the AC distribution network. Traditional Type AC or Type A breakers use iron core transformers that become magnetically saturated by smooth DC leakage currents, causing them to blind and lock (fail to trip under lethal fault conditions). Type B RCCBs employ active electronic sensing algorithms capable of detecting pure DC, high-frequency AC, and composite smooth leakage.
OFA products strictly adhere to ISO9001 quality management guidelines. Our flagship breaker ranges are fully compliant with IEC 60898-1, IEC 60947-2, IEC 61008-1, IEC 61009-1 standards and possess international CE, CCC, and RoHS certifications. Full type test reports are available upon request for municipal and utility tender bids.
OFA provides end-to-end custom manufacturing services. Clients can request customized tripping curves (B, C, D characteristics), tailored current ratings ($I_n$), customized residual trip sensitivities ($I_{\Delta n} = 10\text{mA}, 30\text{mA}, 100\text{mA}, 300\text{mA}$), proprietary silk-screen branding, custom housing colors, laser-engraved QR codes, and specialized multi-pack export packaging.
For standard catalog products (such as standard OFP, OFKL, or OFDX series), OFA maintains buffer stock for quick dispatch within 7 to 10 days. Customized high-volume OEM orders or non-standard voltage configurations typically carry lead times of 20 to 30 days. Shipments are consolidated out of Ningbo or Shanghai sea ports with complete customs documentation.
High-capacity molded case breakers, compact MCBs, and specialized earth leakage protection hardware built to international standards.
OFA Electrical