GRL DNH1-30G Fuse Switch Disconnector 690VAC 160A 250A 400A 630A Use NH fuse link

Fuse Switch Disconnector DNH1-30G  Technical Parameters

GRL DNH1 Series: The New Standard in High-Voltage Protection

In today’s demanding industrial and commercial environments, you cannot compromise on electrical safety or reliability. Standard protection is no longer enough, especially in heavy-duty applications.

This is why GRL is proud to introduce the DNH1 Series Fuse Switch Disconnector—a robust, high-performance line engineered specifically to handle the toughest challenges.

Designed for systems up to AC 690V, the DNH1 series provides critical overcurrent and short-circuit protection while ensuring a safe and reliable means of isolation. With four dedicated frame sizes—160A, 250A, 400A, and 630A—the DNH1 family is the only solution you need for your main distribution and sub-distribution panels.

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Why Choose the GRL DNH1 Fuse Switch Disconnector?

1. Engineered for AC 690V Heavy-Duty Applications

While many standard disconnectors are limited to 400V or 500V, the GRL DNH1 is fully rated for AC 690V. This makes it the perfect choice for demanding industrial plants, mining operations, renewable energy systems (solar and wind), and critical infrastructure where higher voltages are common.

2. A Complete, Versatile Range (160A – 630A)

One product family covers all your needs. The DNH1 series simplifies your engineering, purchasing, and inventory with four optimized frame sizes:

• 160A (DNH1-160)
• 250A (DNH1-250)
• 400A (DNH1-400)
• 630A (DNH1-630)

This scalability allows you to standardize on a single, high-quality platform from GRL, ensuring consistent performance and design across all your projects.

3. Unmatched Protection with NH Fuse Links

The DNH1 series is designed to accommodate industry-standard NH fuse links (sizes NH00, NH1, NH2, and NH3). This provides:

• High Breaking Capacity (kA): Safely interrupts massive short-circuit currents, protecting your valuable downstream equipment.
• Precise Overcurrent Protection: Selectable fuse ratings allow for fine-tuned protection against overloads.
• Cost-Effectiveness: Fuses offer economical and reliable protection that is easily replaceable.

DNH1 Fuse Switch Disconnector Wiring method

Ideal Applications for the DNH1 Series

The robust design and high-voltage rating of the GRL DNH1 make it the ideal choice for:

• Main Power Distribution Boards (MDBs)
• Sub-Distribution Panels
• Motor Control Centers (MCCs)
• Industrial Automation & Machinery
• Renewable Energy (Solar Inverter & Battery Storage systems)
• Commercial Buildings & Data Centers
• Transformers and Generator Protection

DNH1 Fuse Switch Disconnector Product Showcase

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The Role of Fuse Switch Disconnectors in Industrial and Commercial Electrical Systems

In the complex and power-intensive environments of industrial plants and commercial facilities, electrical systems are the circulatory system. But this system operates under constant threat from overcurrents, short circuits, and the need for safe human intervention. Among the arsenal of protective devices, the Fuse Switch Disconnector (FSD) stands out as a critical, multi-function component that ensures safety, reliability, and system integrity.

While often overshadowed by its resettable cousin, the circuit breaker, the Fuse Switch Disconnector plays a unique and indispensable role. Its purpose is elegantly simple: to combine the absolute protection of a fuse with the operational safety of a disconnector.

This article explores the vital roles this device plays in modern industrial and commercial electrical networks.

1. The Core Duality: Protection and Isolation

The fundamental value of an FSD lies in its “dual-function” design, as mandated by standards like IEC 60947-3. It is not just a fuse holder, nor is it just a switch; it is both, integrated into a single, robust unit.

Role 1: Uncompromising Overcurrent Protection (The “Fuse”)

This is the device’s primary protective function. The integrated fuse links (such as the common NH type) provide definitive protection against two main dangers:

• Short-Circuit Protection: In an industrial setting, a short circuit can release catastrophic amounts of energy. Fuses are designed to act almost instantaneously, interrupting fault currents in milliseconds. They inherently possess a very High Breaking Capacity (often 100kA or more), enabling them to safely extinguish an arc and clear a fault far greater than most circuit breakers of a similar size or cost. This is crucial for systems installed near transformers, where potential fault currents are highest.
• Overload Protection: A sustained overload—from a struggling motor or an over-tasked circuit—can cause cables to overheat, leading to insulation failure and fire. The fuse element is precisely engineered to melt and break the circuit if a specific current level is exceeded for a defined time, protecting valuable assets from thermal damage.

Role 2: Verifiable Safe Isolation (The “Disconnector”)

This is the FSD’s critical safety-of-life function. Before any maintenance, repair, or inspection can occur, the circuit must be de-energized and safely isolated.

• “Making” and “Breaking” Load: An FSD is designed to be operated under load. It can safely switch on and off a circuit’s normal operating current.
• Creating a Safe Working Environment: More importantly, when in the “OFF” position, it provides a positive, visible air gap between the supply and the load. This physical separation is a non-negotiable requirement for maintenance, allowing personnel to perform Lockout/Tagout (LOTO) procedures with confidence, knowing the downstream circuit is completely dead.

2. Key Applications in Industrial Settings

In heavy industry (manufacturing, chemical processing, mining), the electrical demands are extreme. The role of the FSD is focused on robustness and high performance.

• Main Feeder Protection: FSDs are commonly used in main distribution boards (MDBs) to protect the primary feeders supplying power to different zones of a plant or to large sub-distribution panels. Their high breaking capacity is essential here.
• Motor Protection: Large industrial motors have high in-rush currents on startup. Fuses (specifically aM-type fuses) are ideal for this, as they can withstand this temporary in-rush without tripping, yet still provide instant protection against a damaging short circuit. The FSD acts as the motor’s local isolator and fault protector.
• Capacitor Bank Protection: FSDs are used to protect capacitor banks used for power factor correction, guarding them against fault currents that could cause them to fail catastrophically.

3. Key Applications in Commercial Systems

In commercial buildings (office towers, data centers, hospitals), the focus shifts slightly towards reliability, uptime, and modularity.

• Sub-Distribution Panels: FSDs are a cost-effective and space-saving solution for protecting and isolating sub-mains circuits feeding different floors or critical service areas (e.g., HVAC, elevator banks).
• Critical Power (Data Centers & Hospitals): In these environments, uptime is paramount. While breakers are common, FSDs are often used for main switchgear where their high fault rating and simple, reliable operation are valued. There is no complex mechanism to fail; the fuse is a “failsafe” device.
• Renewable Energy Integration: This is a rapidly growing role. FSDs are critical components in solar PV combiner boxes and Battery Energy Storage Systems (BESS). They provide high-voltage DC protection and a necessary means of isolation, which are fundamental safety requirements for these high-energy systems.

4. FSD vs. Circuit Breaker: Choosing the Right Tool

A common question is, “Why not just use a circuit breaker?” The choice depends on the application:

The Fuse Switch Disconnector is far from being an outdated technology. It is a purpose-built guardian for industrial and commercial electrical systems.

Its role is to provide a powerful, reliable, and cost-effective combination of two non-negotiable functions: uncompromising protection against the most severe electrical faults and verifiable isolation to ensure human safety. In an age of increasingly complex systems, the simple, robust certainty offered by the FSD makes it a foundational element of modern electrical design.