Brick Fuses High performance Industrial Fuses Selection And Application Guide

Introduction

In modern electrical systems, Brick Fuses (module fuses) have become the preferred protective components for industrial, commercial and civil distribution cabinets due to their advantages such as small size, high breaking energy and visual status indication. This article will focus on the core keyword "Brick Fuses", and construct a clearly hierarchical content framework from product overview, type characteristics, selection strategies, installation and maintenance to application scenarios, to help you quickly obtain high-value information and improve website ranking and user experience.

What are Brick Fuses

Brick Fuses, also known as NH fuses or modular fuses, are typically composed of a rectangular ceramic or high-strength polymer body and metal end caps. Their design objective is to interrupt high current faults within a few milliseconds, thereby protecting circuits and equipment and reducing fault losses.

Selling Points

• Compact "brick" shape, saving space in the distribution cabinet 
• Breaking capacity up to 50 kA - 200 kA, arc-resistant and fireproof 
• Visual indicator window for quick identification of fuse status

Types and Characteristics of Brick Fuses

Classified by rated current

• Low-power type: 0.5A - 10A, mainly used for weak current control
• Medium and high current type: 10 A - 500 A, commonly found in power distribution

Classified by voltage level

• Low-voltage type (230 V - 690 V AC)
• Medium voltage type (up to 15 kV AC)

Classified by protection characteristics

How to choose Brick Fuses

Clarify the usage scenarios and protection targets

First, determine what system the fuse is used for and which type of component or circuit it protects?

Precisely match the electrical parameters

Current Rating

Selection suggestion: ≥ 125% of the maximum working current under load; 
Additional factors such as environmental temperature, ventilation conditions, and cable length should also be taken into consideration; 
Load normal current is 80A. It is recommended to choose a fuse with a capacity of 100A.

Voltage Rating

The rated voltage of the fuse must be ≥ the maximum operating voltage of the system.
AC and DC fuses cannot be used interchangeably.
Medium-voltage Brick Fuses should be selected for high-voltage systems to avoid breakdown.

Breaking Capacity / Interrupting Rating

It should be ≥ the maximum short-circuit current that may occur at the installation point;
High-breaking capacity fuses with a breaking capacity of ≥ 50kA are often selected for industrial systems.
For data centers and substations, it is recommended to choose models with a capacity of ≥ 100kA.

Fuse characteristic curve matching

Different devices have different tolerances for overload, and the matching fuse characteristic curve should be selected:

Check the installation dimensions and compatibility

The dimensions of Brick Fuses are usually in accordance with the NH numbering standards (NH00, NH0, NH1, NH2, NH3);
It should be confirmed whether the fuse body is compatible with the original fuse seat and cable fixture.
If it is installed on a DIN rail, a fuse holder that supports DIN should be selected.

Safety regulation certification and standard compliance

When selecting the model, it should be ensured that the product has been certified by authoritative institutions and possesses the following qualifications:

IEC 60269: International Common Fuse Standards (gG, aM, gR types)
UL 248-13: North American standard, applicable to industrial control equipment
RoHS/REACH: Environmental Compliance requirements
CE/CSA/TUV: Necessary certifications for export to the European and American markets

Certification not only concerns security, but also affects the legality of procurement and the acceptance of terminal equipment.

Consider the usage environment and installation conditions

Temperature influence: If the ambient temperature is too high, the fuse needs to be used at a reduced capacity.
Installation direction: Vertical installation is conducive to heat dissipation and avoids hanging upside down.
Protection grade: For outdoor or humid environments, a closed model with a protective shell (such as IP20/IP65) should be selected.
Seismic resistance and corrosion resistance: Special scenarios such as wind power towers and rail transit have higher requirements for reliability.

Example : Brick Fuse selection for 380V industrial motors

Rated current of the motor: 75A, starting current is approximately 5× 
It is recommended to use the aM type fuse with a rated current of 100A and a breaking capacity of 80kA. 
Select the NH1 model, which complies with the IEC 60269 standard.

Best practices for installation and maintenance

To ensure that Brick Fuses always performs the best protection throughout its service life, the following are more detailed installation and maintenance suggestions:

Check before installation

• Appearance and packaging: Confirm that the fuse housing is free from damage, cracks, dust or contamination, and that the packaging labels and specifications are complete and clear.
• Environmental confirmation: Measure the on-site temperature and humidity to ensure they are consistent with the rated environment of the fuse. Check whether the installation space is well-ventilated.

The correct installation steps

Power-off operation: Make sure to install the fuse only after the main power supply is cut off. Lock and tag the switch to prevent accidental closing. 
Fuse holder and rail: 

• Select the fuse holder corresponding to the NH model to avoid loosening. 
• When installing the DIN rail, ensure that the rail is firmly fixed and level. 

Wiring and Terminal Tightening: 

• Tighten the end cap nut with a torque wrench to the manufacturer's recommended torque (such as 2.5 - 3.0 N·m). 
• The stripping length of the wire end should be moderate, and the insulation layer should not exceed the terminal limit. 

Symmetrical installation: In three-phase or multi-circuit systems, fuses should be installed in a uniform direction to facilitate subsequent comparison and replacement.

Maintenance and regular inspection

Visual inspection (monthly/quarterly)

• Observe the fuse status through the indicator window;
• Check whether the end caps and fuse holders have overheating, discoloration, deformation or carbonization.

Thermal imaging inspection (annually)

• Use an infrared thermal imager to scan terminals and wires. If hot spots (with a temperature difference of ≥10℃) are found, handle them promptly.

Tightness check (half a year)

• Recheck the torque of all wiring screws to prevent poor contact caused by vibration loosening.

Cleaning and maintenance (depending on the on-site environment)

• Anti-static brushes are used for cleaning in industrial dust environments.
• In damp or corrosive areas, the metal end caps can be wiped with a contact cleaner to prevent oxidation.

Emergency response and replacement procedures for faults

Identify the faulty fuse: 

• Check the instruction label and number, and confirm the fuse position. 
• Use a multimeter to measure and confirm that it has been disconnected. 

Safe power-off: Follow the three-level power-off procedure and lock the relevant switches. 
Replacement operation: 

• Wear insulating gloves and goggles; 
• Replace with new products of the same model and characteristics. It is strictly prohibited to temporarily substitute non-standard products. 

Test before power restoration: 

• First, install the fuse and close the switch without load to confirm there are no abnormal sounds or sparks. 
• After power-on, use a clamp meter to measure the current and phase-to-phase voltage to ensure the system is functioning properly.