​Chint Surge Protective Device (SPD) NXU-I+II 12.5/275

chint Surge Protective Device (SPD) NXU-I+II 12.5/275 is a dual-protection product specifically designed for low-voltage power distribution systems. It integrates Class T1 (10/350μs waveform) and Class T2 (8/20μs waveform) surge suppression technologies, and is suitable for protecting residential, comercial, and industrial environments against lightning-induced overvoltages and switching overvoltages. Below is a detailed analysis of its core information:

1. Technical Parameters and Protection Capability
2. Core Performance Indicators

Maximum Continuous Operating Voltage (Uc): 275V (suitable for 230V single-phase or 400V three-phase systems).

Discharge Current:

– Class T1 Iimp (10/350μs): 12.5el (for discharging direct lightning energy).

– Class T2 Imax (8/20μs): 50el (for suppressing induced lightning and switching overvoltages).

Voltage Protection Level (Up): ≤1.5kV (L-PE/N-PE paths), effectively protecting equipment from residual voltage damage.

Tiempo de respuesta: ≤25ns, quickly intercepting transient overvoltages.

2. Mecanismo de doble protección

Class T1: Uses a Gas Discharge Tube (GDT) to discharge the high energy of direct lightning, reducing the impact load on subsequent circuits.

Class T2: Adopts a Metal Oxide Varistor (MOV) to further limit voltage, ensuring the voltage of terminal equipment stays within a safe range.

Escenarios de aplicación: Suitable for the incoming line terminals of small and medium-sized buildings (such as villas and shops) or areas with moderate thunderstorm activity (30-60 thunderstorm days per year). It needs to be used with downstream Class T2 SPDs (with a distance of ≥10m or additional decouplers) to achieve multi-level protection.

1. Design Features and Reliability
2. Safety and Durability

Estructura modular: Plug-and-play design for easy maintenance, supporting remote alarm contacts (optional) for real-time monitoring of operating status.

Thermal Trip Protection: When internal components age or overheat, it automatically disconnects the circuit and triggers a red indicator to prompt replacement.

Material and Environmental Adaptability:

– The housing is made of flame-retardant material with an IP20 protection rating, capable of withstanding extreme temperatures from -40℃ to +70℃.

– Suitable for environments with Pollution Degree 2 and an altitude of ≤2000m.

2. Certificaciones y estándares

– Cumple con IEC/EN 61643-11 y GB/T 18802.11 estándares, and has obtained CQC, CE, and CB certifications, ensuring global applicability and quality reliability.

– Compatible with the NXSCB dedicated protection device (to be purchased separately), which can quickly interrupt circuits in case of short circuits, reducing the risk of fire.

III. Pautas de instalación y mantenimiento

1. Requisitos de instalación

Método de cableado: Supports full-mode protection for L-PE, N-PE, and L-N, and is compatible with TT and TN power grid systems.

DIN Rail Installation: Uses TH35-7.5/DIN35 standard rails, with a compact installation size (p.ej., 70mm width for the 4P model), saving space in distribution boxes.

Grounding Specifications: The grounding wire must be independent with a cross-sectional area of ≥16mm² to ensure a low-impedance current discharge path.

2. Puntos clave de mantenimiento

Inspección periódica: Before the thunderstorm season every year, confirm the operating status through the status indicator window (green for normal, red for replacement required) or remote signals.

Replacement Cycle: The service life is approximately 5-8 years under normal use; if frequent lightning strikes occur, early inspection is required.

Warranty Policy: Provides a 36-month warranty from the date of factory shipment; free replacement is available for non-human-induced damages.

1. Escenarios de aplicación y recomendaciones de selección
2. Aplicaciones típicas

Residential and Commercial: Protects air conditioners, refrigeradores, smart home systems, etc., from lightning impacts.

Industrial and Infrastructure: Suitable for protecting the main incoming lines of equipment such as distribution boxes and control cabinets, especially for sensitive equipment like photovoltaic inverters.

Lightning-Prone Area Protection: Used with downstream Class T2 SPDs (p.ej., NXU-II 40kA) to form a three-level protection system, mejorando la confiabilidad del sistema.

2. Selection Precautions

Coincidencia de voltaje: Select the Uc value (275V or 385V) according to the power grid voltage to avoid component aging caused by long-term overvoltage.

Current Carrying Capacity: If the number of thunderstorm days per year exceeds 60, it is recommended to upgrade to a higher specification (p.ej., NXU-I+II 25kA).

Supporting Equipment: Priority should be given to selecting decouplers or backup protection fuses of the same brand (p.ej., NSCB5-I+II 12.5H) to ensure compatibility.

1. Market Reference and Purchase Recommendations
2. Gama de precios

– The price of the 4P model is approximately 78-186 RMB on mainstream e-commerce platforms (such as Tmall and JD.com) in 2025, with specific fluctuations depending on channels and functional differences (p.ej., with remote signaling contacts).

– For bulk industrial purchases, discounts can be obtained through Chint-authorized distributors; system parameters (such as cable length and lightning strike risk level) need to be provided for customized solutions.

– WhatsApp for inquiries in 2025: 0086-13811255435

1. User Reviews and Reputation

Advantage Feedback: Users generally recognize its easy installation and stability, especially its excellent performance in lightning-prone areas.

Precauciones: Some users suggest adding moisture-proof measures in high-humidity environments to prevent performance impacts caused by condensation.

Resumen

With its dual protection mechanism, high-reliability design, y amplia aplicabilidad, Chint NXU-I+II 12.5/275 Surge Protective Device has become an ideal choice for low-voltage power distribution systems. Its strict standard certifications, clear status indication, and convenient maintenance features can effectively reduce damage to equipment caused by lightning strikes and switching overvoltages, providing long-term safety protection for residential, comercial, and industrial users. When selecting the product, it is necessary to consider the actual application scenario and power grid parameters; if necessary, consult professional engineers to optimize the protection scheme.