Explore our tier-1 engineered NB1L Series RCBOs, MCBs, and MCCBs built to international IEC/EN standards for high-demand commercial and industrial installations.
Rooted in Yueqing, Wenzhou—the world-renowned Capital of Electrical Appliances in China—Wenzhou OFA Electrical Technology Co., Ltd. (founded in 2013) has established itself as an industry powerhouse in distribution switchgear, low-voltage protective devices, and intelligent power control systems. Under our proprietary brand "OFA", we deliver robust engineering solutions across electrical infrastructure, renewable energy, industrial automation, commercial construction, and equipment manufacturing.
Modern low-voltage power distribution networks face unprecedented electrical stresses due to harmonic distortions, non-linear industrial loads, and bidirectional currents from solar PV microgrids. The NB1L Series Residual Current Circuit Breakers with Overcurrent Protection (RCBO) represent the pinnacle of combined earth-leakage, thermal overload, and short-circuit protection engineered into a compact modular enclosure.
Our plant is fully ISO9001 quality management certified, implementing strict 100% full-inspection SOPs from raw metallic alloy sourcing to end-of-line trip curve verification.
A rigorous examination of electrical trip dynamics, residual current detection thresholds, breaking capacities, and selective coordination compliance according to IEC/EN 61009-1 and IEC/EN 60898-1.
The NB1L Series RCBO is an integrated device designed to replace legacy two-component protection schemes (separate MCB + RCCB). Legacy setups require dual DIN-rail slots, additional interconnecting copper busbars, and increased installation labor, while presenting potential thermal hot spots at wire terminal junctions. The NB1L series integrates zero-sequence current transformer core sensing, an electromagnetic trip latch, and a precision bimetallic thermal element into a single, high-density flame-retardant housing.
| Technical Feature | NB1L Specification Benchmark | Engineering Benefit & Application Impact |
|---|---|---|
| Standard Compliance | IEC/EN 61009-1, IEC/EN 60898-1, GB 16917.1 | Ensures universal compliance across European, Asian, Latin American, and Middle Eastern utility grids. |
| Poles Configuration | 1P+N (Switched Neutral), 2P, 3P, 3P+N, 4P | Provides complete phase isolation and line neutral breaking for single-phase & 3-phase industrial networks. |
| Rated Current (In) | 1A, 2A, 4A, 6A, 10A, 16A, 20A, 25A, 32A, 40A, 50A, 63A | Granular current rating matching for precise motor, lighting, sub-panel, and feeder circuit protection. |
| Residual Current Waveform Type | Type AC (Sinusoidal), Type A (Pulsating DC), Type B (Smooth DC) | Protects sensitive electronic controls, variable frequency drives (VFDs), and solar inverter leakage path. |
| Rated Residual Sensitivity (IΔn) | 10mA (High Sensitivity), 30mA (Life Safety), 100mA / 300mA (Fire Prevention) | 30mA provides direct human contact protection; 100/300mA prevents electrical fire ignitions. |
| Ultimate Short-Circuit Capacity (Icu) | 6,000A (6kA) / 10,000A (10kA) at 230/400V AC | Rapid arc extinction within 3-5 milliseconds, neutralizing high fault currents safely. |
| Instantaneous Tripping Curve | B Curve (3-5 In), C Curve (5-10 In), D Curve (10-14 In) | Tailored magnetic response for resistive loads (B), inductive commercial loads (C), and high-inrush transformers (D). |
| Electrical & Mechanical Endurance | Mechanical: 20,000 Operations | Electrical: 10,000 Operations | Long service life under intensive industrial switching cycles and heavy thermal stress. |
Utilizes ultra-high magnetic permeability permalloy toroidal cores to detect vector sum imbalances as small as 5mA, driving high-speed magnetic relays within milliseconds of fault initiation.
Engineered with a 12-plate arc-extinguishing chamber that splits, cools, and quenches electrical arcs rapidly, minimizing contact erosion and preventing enclosure rupture during heavy short circuits.
Visual red/green flag indicator mechanically connected to the internal contact assembly provides unambiguous verification of physical contact separation for safe lock-out/tag-out (LOTO) procedures.
How Wenzhou OFA Electrical Technology Co., Ltd. resolves cost, quality, and lead-time friction for international B2B buyers, EPC contractors, and OEM panel builders.
Seamlessly integrated power protection designed for demanding, mission-critical deployment environments across municipal, commercial, and renewable sectors.
Protects AC output circuits of string inverters from earth leakage currents induced by high parasitic capacitance in PV panels. Type A and Type B NB1L RCBOs prevent blind spots caused by smooth DC leakage components.
Essential protection for AC Wallboxes and DC fast charger auxiliary control sub-panels. Prevents electric shock hazards to vehicle users while guarding internal sensitive power electronic modules against line surges.
High reliability with selective 100mA/300mA delayed trip models prevents cascade shutdowns across server racks. Ensures continuous uptime for IT equipment while guaranteeing strict fire safety compliance.
Compact 1P+N width saves 50% cabinet space in modern high-density retail and office distribution boards, allowing panel builders to double circuit density without increasing enclosure size.
Resists high electromagnetic interference (EMI) and transient voltage spikes typical of heavy industrial environments with motor drives, welding machinery, and automated conveyor lines.
Enables reliable outdoor street lighting and municipal pump station control with enhanced humidity resistance, anti-vibration terminals, and extreme temperature tolerance (-25°C to +60°C).
From initial design requirement alignment to agile mass production, Wenzhou OFA Electrical Technology Co., Ltd. ensures a frictionless collaboration journey.
Ideal for commercial retrofits, building distributors, and standard PV system integration requiring proven, stocked protective components.
Tailored for global electrical product brands, original panel manufacturers, and regional enterprise distribution projects.
How Wenzhou OFA Electrical Technology Co., Ltd. is advancing low-voltage breaker architecture to meet Next-Generation Grid Requirements.
Integrating micro-sensors and Modbus/RS485 wireless communications directly into smart RCBO bodies. Real-time telemetry predicts insulator breakdown before catastrophic earth faults occur.
Developing next-gen Type B+ RCBOs optimized to detect high-frequency harmonic leakage currents up to 100 kHz, crucial for high-speed silicon carbide (SiC) power converters in EV chargers.
Transitioning toward 100% recyclable engineering polymers and halogen-free contact matrixes to support global net-zero sustainability mandates and European RoHS/REACH standards.
See why global system integrators, plant engineers, and electrical distributors depend on OFA for their critical protection infrastructure.
"We purchased OFA's intelligent power monitoring and NB1L series devices to upgrade the power distribution system in our old workshop. The installation was simpler than expected, and integration went smoothly. Most importantly, they have been running stably for over a year, helping us catch previously unnoticed power anomalies."
"As a system integrator, our company has collaborated with OFA on several industrial automation projects. Their product range is remarkably comprehensive, covering protective relays, MCBs, MCCBs, and RCBOs, simplifying our global procurement. Contact quality is consistent, eliminating commissioning friction."
"Deploying OFA's energy efficiency management devices for several commercial office towers was a wise operational move. The clear technical documentation made system pairing intuitive, and their remote engineering support team responded rapidly whenever we needed assistance."
"Our remote PV solar project required high reliability under severe ambient temperatures. OFA's NB1L RCBOs met our technical parameters perfectly at a very competitive price point. Their technical support engineers provided fantastic configuration assistance via video calls."
Detailed technical, operational, and procurement guidance for prospective B2B buyers and project engineers.
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