500 Volt Fuse-Bases to IEC 60269-2 – Type LSPN/DIN

500V Fuse Bases to IEC 60269-2 – Type DFB (LSPN/DIN) NH Type Fuse Base | Knife Blade Fuse Base | DIN Type Fuse Base | Steel Fuse Base | Square Body Fuse Base | Size 00 | Size 1 | Size 2 | Size 3 Fuse Base | DMFC Fuse Base

Product Introduction

The Lawson Type DFB is a comprehensive range of NH Type Fuse Bases designed for use in conjunction with 500V NH type industrial fuse-links with knife blade contacts. As a certified Knife Blade Fuse Base and DIN Type Fuse Base, the Type DFB range covers the four standard NH fuse sizes — Size 00, Size 1, Size 2, and Size 3 — in current ratings from 160A to 630A, providing the fixed mounting infrastructure for NH fuse-links across the full range of industrial distribution, switchgear, and panel building applications.

The Steel Fuse Base construction of the Type DFB provides mechanical robustness and long service life in demanding industrial environments, while the Square Body Fuse Base form factor of the NH system ensures compatibility with standard DIN-compliant busbar, panel-mount, and switchgear equipment across the UK and internationally. Compliant with IEC 60269-2, the Type DFB NH Type Fuse Base is fully matched to the Lawson Type LSPN/DIN range of 500V NH industrial fuse-links with knife blade contacts — ensuring a coordinated, certified fuse and base system for industrial protection applications.

Key Features

• NH Type Fuse Base — for use with 500V NH type industrial fuse-links with knife blade contacts
• Knife Blade Fuse Base — accepts NH knife-blade contact fuse-links in standard DIN sizes 00, 1, 2, and 3
• DIN Type Fuse Base — standardised DIN NH fuse base dimensions for compatibility with industrial panel equipment
• Steel Fuse Base construction — robust, durable metal construction for demanding industrial installation environments
• Square Body Fuse Base (NH format) — the internationally recognised square/oblong NH body format with blade contacts
• Available in four sizes: Size 00 (160A), Size 1 (250A), Size 2 (400A), Size 3 (630A)
• Rated 500V — suitable for three-phase industrial supply systems
• Compliant with IEC 60269-2 — the international standard for industrial fuse-links and associated equipment
• DMFC Fuse Base compatible — compatible with DIN NH fuse-link sizes used in DMFC and similar industrial distribution equipment
• Used in conjunction with Lawson Type LSPN/DIN 500V NH Industrial Fuse-Links
• Compatible with Lawson Type LUCH NH Universal Replacement Handle

NH Fuse Base Size Guide

Size 00 NH Fuse Base (DFB00) — 160A The Size 00 Fuse Base (DFB00) is the smallest in the Type DFB range, rated at 160A with M8 fixing bolts. It provides a compact Knife Blade Fuse Base footprint for use in smaller industrial distribution boards, sub-circuit panels, and switchgear assemblies where space is at a premium but NH-format protection is required.

Size 1 NH Fuse Base (DFB01) — 250A The Size 1 Fuse Base (DFB01) is rated at 250A with M10 fixing bolts and provides a mid-range NH Type Fuse Base suitable for sub-main distribution, motor feeder fusing, and transformer secondary protection in industrial panels.

Size 2 NH Fuse Base (DFB02) — 400A The Size 2 Fuse Base (DFB02) is rated at 400A with M10 fixing bolts and is one of the most widely used DIN Type Fuse Base sizes in industrial distribution equipment — suitable for main circuit protection in motor control centres, primary distribution boards, and busbar-mounted switchfuse assemblies.

Size 3 NH Fuse Base (DFB03) — 630A The Size 3 Fuse Base (DFB03) is the largest in the Type DFB range, rated at 630A with M12 fixing bolts. This Steel Fuse Base provides the high-current Knife Blade Fuse Base solution for main incomer protection, large transformer feeders, and primary distribution in the most demanding industrial electrical installations.

Applications

The Lawson Type DFB NH Type Fuse Base, Knife Blade Fuse Base, and DIN Type Fuse Base range is specified across a wide range of industrial and commercial applications:

• Industrial distribution boards and MCC main circuits — Size 1, 2 and 3 NH Type Fuse Bases for main and sub-main incoming supply fusing
• Primary transformer protection — high-current Steel Fuse Base mounting for transformer primary and secondary side NH fuse-links
• Motor control centres (MCCs) — NH fuse bases for large motor feeder and incomer circuits
• Industrial switchgear and busbar chambers — panel-mounted DIN Type Fuse Base assemblies in three-phase switchgear
• Power distribution in heavy industry — steel works, chemical plant, mining, and process industries requiring robust high-current fuse bases
• Building services distribution — main and sub-main distribution in large commercial and industrial buildings
• Utilities and water industry — pump station, treatment works, and pumping main distribution protection
• Railway and infrastructure — high-current distribution protection in railway depot, tunnel, and infrastructure applications

Why Choose Lawson Type DFB Fuse Bases?

The Lawson Type DFB NH Type Fuse Base range is specifically designed and dimensionally matched to work with the Lawson Type LSPN/DIN 500V NH industrial fuse-links — ensuring that the complete Knife Blade Fuse Base and fuse-link assembly meets the performance requirements of IEC 60269-2 as a coordinated, certified protection system. The Steel Fuse Base construction provides the mechanical robustness and thermal performance required for the demanding fault-level and load-current environments typical of industrial distribution equipment.

With four sizes covering 160A to 630A, M8 to M12 fixing bolt sizes, and full DIN-standardised Square Body Fuse Base dimensions, the Type DFB range provides a complete DIN Type Fuse Base solution for industrial panel builders, switchgear manufacturers, and electrical contractors across the full NH fuse size range.

All Lawson products are manufactured under an ISO 9001 accredited quality management system with test facilities independently accredited to ISO/IEC 17025, and comply with IEC 60269-2 — the international standard for industrial fuse equipment.

Q1. What is an NH Type Fuse Base?

An NH Type Fuse Base is the fixed base component of the NH (Niederspannungs-Hochleistungs) fuse system — the industrial high-rupturing-capacity fuse system using knife blade contact fuse-links in standardised square or oblong body sizes. The fuse base provides the fixed electrical contacts, wiring terminals, and mechanical support for NH fuse-links, which are inserted and locked in place using an NH fuse handle. The Lawson Type DFB is an NH Type Fuse Base available in sizes 00, 1, 2, and 3, rated 160A to 630A at 500V, compliant with IEC 60269-2.

Q2. What is a Knife Blade Fuse Base?

A Knife Blade Fuse Base is an NH fuse base designed to accept NH fuse-links that connect via flat blade-type knife contacts — the distinctive wide, flat metal contact strips on either end of an NH fuse-link body. When the NH fuse-link is inserted into the base, the knife blades engage with spring-loaded contacts in the base, creating a firm, low-resistance electrical connection. The knife blade connection system is a fundamental feature of the NH DIN fuse format and distinguishes it from bolted-tag and cylindrical fuse systems.

Q3. What is a DIN Type Fuse Base?

A DIN Type Fuse Base is an NH fuse base conforming to the DIN (Deutsches Institut für Normung) dimensional standards for the NH fuse system — also standardised under IEC 60269-2. DIN Type Fuse Bases are designed with standardised mounting dimensions, contact spacing, and fixing bolt sizes that ensure compatibility with NH fuse-links from any manufacturer conforming to the same DIN/IEC NH standard. The Lawson Type DFB is a fully DIN-standardised DIN Type Fuse Base covering NH sizes 00, 1, 2, and 3.

Q4. What is a Steel Fuse Base and why is it used?

A Steel Fuse Base is an NH fuse base with a steel or metal body construction — providing greater mechanical robustness, higher thermal performance, and longer service life than plastic-bodied fuse bases, particularly in demanding industrial environments where high load currents, elevated ambient temperatures, and exposure to vibration or mechanical stress are factors. The Lawson Type DFB Steel Fuse Base is the appropriate choice for main distribution, switchgear, and busbar applications in industrial installations.

Q5. What is a Square Body Fuse Base?

A Square Body Fuse Base refers to the characteristic square or oblong cross-sectional profile of the NH fuse-link body and its associated fuse base format — distinguishing the NH system from cylindrical and wedge-tag fuse systems. The square body and knife blade contact design of the NH system allows it to handle much higher breaking capacities (typically 120kA) than screw-cap or bolted-tag fuse systems of equivalent current rating, making it the dominant format in European industrial high-current fuse protection.

Q6. What NH fuse sizes does the Type DFB range cover and what are their current ratings?

The Lawson Type DFB NH Type Fuse Base range covers four sizes: Size 00 (DFB00, 160A), Size 1 (DFB01, 250A), Size 2 (DFB02, 400A), and Size 3 (DFB03, 630A) — all rated at 500V in compliance with IEC 60269-2.

Q7. What is a DMFC Fuse Base?

DMFC refers to a type of DIN-standardised NH fuse base used in modular fuse combination switches and similar industrial distribution equipment. The Lawson Type DFB DIN Type Fuse Base is compatible with the dimensional requirements of DMFC and similar DIN NH fuse equipment, making it suitable for use in a wide range of modular industrial distribution and switchfuse assemblies that accept standard DIN NH fuse bases.

Q8. What is the difference between Size 00, Size 1, Size 2, and Size 3 NH Fuse Bases?

The NH size designation defines both the physical dimensions of the fuse base contacts and housing, and the maximum current rating the base is designed to accommodate. Size 00 is the smallest, rated 160A, with M8 fixing bolts. Size 1 (250A) and Size 2 (400A) share common overall width and depth dimensions with M10 fixing bolts, differing primarily in height and contact spacing. Size 3 (630A) is the largest, with M12 fixing bolts and the greatest dimensions, designed for the highest current NH fuse-links. NH fuse-link sizes are not interchangeable between fuse base sizes — the fuse-link size must always match the base size.

Q9. What NH fuse-links are compatible with the Lawson Type DFB Fuse Base?

The Lawson Type DFB Knife Blade Fuse Base range is designed for use with Lawson Type LSPN/DIN 500V NH industrial fuse-links with knife blade contacts in the corresponding NH size (00, 1, 2, or 3). NH fuse-links from other manufacturers conforming to the same DIN/IEC 60269-2 NH dimensional standard are also dimensionally compatible — however, always ensure the voltage rating, current rating, and breaking capacity of the fuse-link are appropriate for the specific application and installation.

Q10. How do I order the Lawson Type DFB NH Type Fuse Base?

The full Lawson Type DFB NH Type Fuse Base, Knife Blade Fuse Base, and DIN Type Fuse Base range — covering Size 00 (DFB00), Size 1 (DFB01), Size 2 (DFB02), and Size 3 (DFB03) — is available through the Lawson Fuses sales team and their network of authorised sales partners and electrical wholesalers across the UK. Contact Lawson Fuses directly for trade pricing, availability by size, and technical support for your industrial switchgear or panel building project.