Explore our precision-engineered Miniature Circuit Breakers (MCB), Molded Case Circuit Breakers (MCCB), and Earth Leakage Devices engineered for heavy-duty industrial control panels.
Founded in 2013, Wenzhou OFA Electrical Technology Co., Ltd. is rooted in Yueqing, Wenzhou—widely recognized as the Capital of Electrical Appliances in China. We operate as a tier-one designer, manufacturer, and global exporter of low-voltage distribution switchgear, intelligent control equipment, and circuit protection components.
Owning proprietary brands such as "OFA", our solution architecture bridges the physical engineering gaps in industrial automation, renewable energy integration (Solar PV/BESS), commercial power panels, and utility-scale infrastructure projects.
Tax Credit Grade A Compliance (7 Consecutive Years)
Demonstrating financial transparency, legally compliant operational governance, and long-term buyer trust across 50+ global export destinations.
Our full-process manufacturing standard operating procedures (SOP) incorporate 100% routine testing for mechanical operational endurance, temperature rise limits, dielectric withstand, and trip calibration sensitivity prior to export dispatch.
As industrial automation, motor control centers (MCC), and distributed energy resources (DER) evolve toward higher power densities and micro-grid complexity, the demands placed on control panel circuit breakers have shifted radically from simple passive protection to active, intelligent system resilience.
Modern industrial power feeds exhibit exceptionally high fault-current availability. Control panel protection devices must deliver ultimate short-circuit breaking capacities (Icu) reaching 10kA to 100kA under IEC 60947-2 standards without suffering contact welding or structural dielectric degradation.
With the exponential expansion of Solar PV array combiners, Battery Energy Storage Systems (BESS), and DC microgrids, circuit breakers face the absence of natural zero-crossing points during arc extinguishing. Special high-magnetic blowout channels are critical to stretch and extinguish high-voltage DC arcs quickly.
System integrators face increasing enclosure space constraints. Modern circuit breakers require optimized copper conductor geometries, low internal contact resistance, and flame-retardant VO-rated polycarbonates to minimize heat dissipation inside enclosed IP65/IP67 control cabinets.
Select the precise protection mechanism matching your system architecture: from sub-distribution branch protection to main panel intelligent air circuit breakers.
Ranging from 16A to 1600A rated current, OFA MCCBs (such as our OFA-M1 and BLTM3DC series) serve as primary feeder switchgear. Featuring adjustable thermal-magnetic or microprocessor-based electronic trip units (ETU), they provide precise long-time delay (L), short-time delay (S), instantaneous (I), and ground-fault (G) protection curves.
Designed for standard 35mm DIN rail mounting, OFA MCBs (OF6KA, OF10KA, OFD4Z7) safeguard end-user branch circuits up to 125A. Available in B, C, D, K, and Z tripping characteristics, they isolate overloads and short circuits in sub-cycle response times (< 2.5ms).
Our OFW1 Intelligent Universal ACB series engineered for main incoming distribution boards up to 6300A. Built with dual-bus communication interfaces (Modbus-RTU, PROFIBUS, Ethernet), real-time power quality monitoring, and selective zone interlocking (ZSI) capabilities.
Detecting dangerous vector-sum earth leakage currents to prevent electric shock and electrical fire hazards. Available in Type AC, Type A (pulsating DC sensitive), and Type B (smooth DC residual current detection for EV chargers and inverters).
Combining the functionality of an MCB and RCCB within a single compact module width (1P+N, 2P, 4P). Eliminates nuisance tripping, saves control panel space, and provides selective individual line isolation during earth faults.
Heavy-duty non-automatic switch isolators designed for reliable mechanical isolation during maintenance operations. Features high impulse withstand voltage (Uimp) ratings, padlockable handles, and positive contact position indication.
| Device Series | Primary Function | Rated Current (In) | Breaking Capacity (Icu) | Applicable Standards |
|---|---|---|---|---|
| OFA MCB (OF10KA / OFD4Z7) | Branch Overload & Short-Circuit Protection | 1A – 125A | 6kA / 10kA | IEC/EN 60898-1, IEC 60947-2 |
| OFA MCCB (OFA-M1 / BLTM3) | Feeder Protection & Motor Control isolation | 16A – 1600A | 25kA – 100kA | IEC/EN 60947-2, GB/T 14048.2 |
| OFA RCBO (NB1L / OFC) | Overload, Short Circuit & Life Shock Protection | 6A – 63A | 6kA / 10kA (30mA residual) | IEC/EN 61009-1 |
| OFA DC MCCB (BLTM3DC) | High-Voltage Solar PV & BESS Storage isolation | 100A – 800A | Up to 1500V DC / 20kA | IEC 60947-2 (PV Annex) |
| OFA ACB (OFW1) | Main Incoming Substation & Power Distribution Protection | 630A – 6300A | 85kA – 120kA | IEC/EN 60947-2 |
Global original equipment manufacturers (OEMs) and panel builders face strict compliance barriers depending on target export territories. Wenzhou OFA Electrical Technology Co., Ltd. designs and manufactures circuit protection components conforming strictly to multi-national regulatory frameworks:
Fully compliant with IEC 60947-2 (Industrial Low-Voltage Switchgear) and IEC 60898-1 (Household/Commercial). CE marked with accredited third-party lab verification.
Engineered to meet the insulation creepage/clearance distance requirements and high voltage withstand demands specified for feeder and supplementary branch protection.
Certified under compulsory GB/T 14048 series standards, ensuring seamless deployment in massive domestic industrial projects and Belt & Road infrastructure initiatives.
To ensure reliable continuous operation in harsh industrial environments (chemically corrosive atmospheres, tropical high humidity, high-vibration mining panels), OFA circuit breakers undergo extensive type-testing:
Our components are built into complex control systems powering modern industrial and commercial infrastructure.
Providing precise selectivity and Type-2 coordination for PLC cabinets, variable frequency drives (VFD), and motor starter panels to eliminate unnecessary plant shutdowns during transient overloads.
High-voltage DC MCCBs and disconnect switches rated up to 1500V DC designed specifically for string combiners, central inverters, and lithium battery containerized protection systems.
Ultra-fast response circuit breakers for Power Distribution Units (PDUs) and uninterruptible power supply (UPS) systems, preventing continuous wave harmonic distortion trip failures.
Integrating Type B RCCBs and high-breaking MCBs to protect EV chargers against continuous smooth DC residual currents and complex high-frequency switching noise.
As power electronics redefine electrical distribution, OFA's R&D department is pioneering next-generation technology topologies to shape the future of control panel protection.
Utilizing Silicon Carbide (SiC) and GaN power semiconductors to achieve zero-arc microsecond interruption times (< 10 microseconds), virtually eliminating mechanical contact wear and arc flash hazard risks.
Embedded IoT microcontrollers analyze continuous thermal profiles, contact wear indicators, and high-frequency current signatures to predict insulation degradation before catastrophic short circuits occur.
Integrating fast optical arc sensors with rapid busbar tripping mechanisms to suppress arc flash energy releases to under 1.2 cal/cm², protecting maintenance personnel and control assets.
See why system integrators, plant engineers, and panel builders rely on OFA for critical circuit protection.
"As a system integrator in Poland, we collaborated with OFA on several heavy industrial automation lines. Their MCCB and relay catalog simplified our procurement. Quality is consistently high, drastically reducing our on-site commissioning troubleshooting time."
Technical Director, System Integration (Poland)
"We deployed OFA intelligent power monitoring devices and MCBs to retrofit our manufacturing facility in Munich. Their products have operated flawlessly for over a year without any nuisance trips, providing precise energy anomaly logs."
Maintenance Manager, Manufacturing Plant (Germany)
"Deploying OFA energy efficiency management devices across our commercial property portfolio in Bangkok was extremely successful. Technical support answered our protocol mapping questions in under 2 hours!"
Facilities Supervisor, Commercial Real Estate (Thailand)
"Our utility-scale PV project in Atacama required robust DC breaking gear that withstands thermal fluctuations. OFA's DC MCCBs delivered exceptional reliability under heavy outdoor operating cycles."
Site Lead Engineer, Renewable Energy (Chile)
From standard distribution component sourcing to full OEM/ODM control cabinet customization, our team ensures rapid project execution.
Submit your single-line diagrams (SLD), voltage ratings, breaking capacities (Icu), and operating ambient constraints to our technical engineering team.
Receive a detailed Bill of Materials (BOM), competitive tiered bulk pricing, CAD enclosure dimensional drawings, and type-test verification reports.
Orders enter our automated ISO9001 assembly lines with digital in-process checks, mechanical calibration, and dielectric impulse testing.
Secure sea/air export packaging, complete customs documentation, Certificate of Origin (CO), and lifecycle technical support post-commissioning.
Browse additional high-capacity RCCB, DC Breaker, and specialized Miniature Circuit Breaker units direct from our Yueqing manufacturing hub.
Get authoritative, engineering-grade answers regarding circuit breaker selection, technical parameters, quality standards, and OEM procurement.
The required Icu (specified in kA) is determined by calculating the maximum prospective fault current ($I_{psc}$) available at the circuit breaker's installation point. This requires calculating the upstream transformer capacity ($kVA$), percentage impedance ($%Z$), and the impedance of interconnecting busbars/cables. As a standard safety rule under IEC 60947-2, the breaker's rated Icu must equal or exceed the calculated maximum prospective short-circuit current to prevent explosive arcing or contact welding.
MCBs (Miniature Circuit Breakers) protect final branch circuits up to 125A with fixed thermal-magnetic trip curves. MCCBs (Molded Case Circuit Breakers) serve intermediate sub-distribution feeders from 16A to 1600A, featuring adjustable electronic or thermal-magnetic trip units. ACBs (Air Circuit Breakers) serve as main incoming power guardians for currents up to 6300A, featuring advanced microprocessor protection units, high short-time withstand current ($I_{cw}$), and intelligent bus communication protocols.
Standard Type A RCCBs can only detect sinusoidal AC and pulsating DC residual currents. Modern three-phase EV fast chargers and solar PV inverters utilize active power electronics that can leak smooth, continuous DC earth fault currents. Smooth DC residual currents blind the magnetic core of standard Type A RCCBs, preventing them from tripping during a hazard. Type B RCCBs incorporate specialized dual-magnetic cores to detect smooth DC earth leakage up to 1kHz.
Tripping curves define the magnetic instantaneous trip threshold relative to rated current ($I_n$):
No. AC circuit breakers rely on the natural zero-crossing of alternating current to extinguish electrical arcs inside the arc chute. Direct Current (DC) lacks a zero-crossing point, causing persistent high-temperature electrical arcs during contact opening. Specialized DC circuit breakers (like the OFA BLTM3DC series) utilize permanent magnetic blowout fields and multi-pole series wiring topology to stretch and extinguish high-voltage DC arcs up to 1500V DC safely.
Wenzhou OFA Electrical Technology Co., Ltd. operates under ISO9001 quality management system certification. All export product batches are accompanied by CE compliance documentation, IEC type-test verification certificates, RoHS compliance reports, and full factory routine inspection data sheets (covering temperature rise, mechanical endurance, and calibration accuracy).
OFA Electrical
