EXU3DC-I+II – Type 1+2 DC SPD 800V-1200V

EXU3DC-I+II T1+T2 DC SPD – Lightning and Surge Protection in One Device

The EXU3DC-I+II series T1+T2 DC SPD by HUYU Electric is a 3-pole DIN-rail module that combines Type 1 lightning impulse handling and Type 2 surge protection for DC photovoltaic and energy storage systems up to 1200V DC. It can safely conduct high-energy lightning currents (Iimp 7kA) and absorb surges (Imax 50kA), serving as the first line of defense for PV combiner boxes, inverter DC inputs, and DC distribution cabinets exposed to lightning.

Compliant with IEC 61643-1 and GB 18802.1, the EXU3DC-I+II features thermal disconnection and a bright visual status indicator. With its innovative plug-in replaceable module, maintenance requires no rewiring. It provides robust protection with a ≤100ns response time and a maximum discharge capacity of 50kA. HUYU Electric offers factory-direct OEM/ODM options with comprehensive testing documentation for project buyers and system integrators looking for certified DC lightning protection in large renewable installations.

Technical Data

With an Iimp of 7kA and Imax of 50kA, this Type 1+2 DC surge protector offers robust protection for DC systems. Its design accommodates 3-pole protection — positive, negative, and ground lines in a single unit. Backup fuse ratings (125A or 200A) allow flexible system configurations, while the 355V TOV rating ensures the SPD withstands temporary overvoltages without tripping prematurely.

First-Line Defense for Exposed DC Systems

Unlike T2 SPDs, the EXU3DC-I+II T1+T2 DC SPD can safely handle direct lightning current (10/350µs waveform), making it essential for PV arrays exposed to high lightning risk. Installed at key locations like the DC combiner or inverter panels, it acts as a critical primary protection barrier. Its visual status indicator and remote signaling capabilities provide immediate alerts for end-of-life scenarios. The plug-in module design allows for quick replacements, reducing downtime substantially. With its high wiring capacity, it is suitable for accommodating large cross-sections required for utility-scale installations.

OEM/ODM Supply – Lightning Protection for Critical DC Infrastructure

Buyer’s Guide

How to Select a T1+T2 DC SPD for Lightning-Prone PV Systems

Key criteria for specifying the EXU3DC-I+II in high-exposure DC applications.

1. Type 1+2 vs. Type 2: Why Iimp Matters

A Type 2 SPD handles induced surges with an 8/20µs waveform but cannot conduct the 10/350µs direct lightning current. A T1+T2 DC SPD with a 7kA Iimp rating is essential for systems in open-field or rooftop PV arrays with high lightning exposure or where local codes mandate a Type 1 device. T2-only devices may fail during a direct strike.

2. Voltage Selection and Array Matching

Choose the voltage rating based on the system’s maximum open-circuit voltage (Voc). A 1200V model is suitable for most PV systems. Always ensure the SPD’s Uc rating exceeds the system’s maximum Voc under cold conditions for added safety margins.

3. Coordination with Backup Protection

The EXU3DC-I+II is compatible with backup fuses up to 200A gL/gG. Ensure the fuse is connected in series with the SPD at the DC bus. In combiner boxes, the main DC breaker may serve this function if it meets the specifications. Otherwise, a dedicated fuse holder is required.

4. Installation at the DC Entrance

Install the Type 1+2 DC surge protector at the primary DC entry point, such as the main DC combiner box or inverter DC distribution cabinet. Minimize the length and bends in connecting wires to enhance performance. The 3-pole unit ensures comprehensive protection for positive, negative, and ground lines in a compact design.

Frequently Asked Questions

What is a Type 1+2 DC SPD?

A T1+T2 DC SPD is an integrated surge protective device that combines Type 1 and Type 2 functionalities. It can handle both direct lightning currents (10/350µs waveform, Iimp) and induced surges (8/20µs waveform, Imax). The EXU3DC-I+II is rated for up to 7kA Iimp and 50kA Imax, making it ideal for lightning-prone areas and critical DC applications.

Where should a T1+T2 SPD be installed?

Install the T1+T2 SPD at the main DC entry point to the building or container, such as the main DC combiner box or inverter cabinet. This position intercepts any direct or proximate lightning energy before it affects downstream equipment, ensuring optimal protection.

What is the difference between a surge protection device and a lightning arrester?

A lightning arrester (Type 1 SPD) is designed for high-energy direct lightning currents (10/350µs waveform), while a surge protection device (Type 2 SPD) handles induced surges from nearby lightning strikes or switching (8/20µs waveform). The EXU3DC-I+II combines both functionalities into one device, simplifying installations and ensuring effective protection.

How to test a DC SPD?

Testing involves checking the status window (green for operational, red for replacement needed) and verifying the continuity of the remote signaling contact. Advanced tests require a portable SPD tester to measure parameters like varistor voltage, necessitating SPD disconnection. The EXU3DC-I+II’s plug-in module design allows for quick, safe replacements when needed without extensive system testing.