Plug Fuses - Compact Protection for Modern Electrical Circuits

Plug fuses offer easy, space-saving protection from overloads and short circuits in control panels, motor controls, electronics and more. With a cylindrical body, wide range of ratings and global approvals, GRL fuses are designed for optimal performance and convenience.

Contact our technical experts to find the right plug fuse for your application. High quality products, short lead times and excellent customer service are assured.

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Introduction

Plug fuses, also known as cartridge fuses, are compact, cylindrical fuses that are widely used for circuit protection in industrial controls, switchgear, and electronic devices. Ease of installation and replacement makes plug fuses a convenient option compared to blade fuses or fuse holders.

Plug fuses consist of a plastic or fiber body that houses a fusible element. The most common sizes are 5x20mm and 6.3x32mm which can directly plug into equipment fuse clips or terminals. Cartridge fuses are available in fast-acting and time-delay varieties to suit specific applications.

With plug fuses, overcurrent protection can be easily incorporated into control panels, motor starters, power supplies and electronic circuits without needing large fuse holders or disconnects. Their cylindrical shape packs reliable protection in a small footprint.

Types of Plug Fuses

There are several construction standards and styles for plug fuses covering different voltage and current ratings.

Ceramic Body Fuses

Ceramic cartridge fuses have a cylindrical body made from ceramic material that provides high dielectric strength and thermal stability. The internal fuse element may be enclosed in glass or mica laminations. Ceramic fuses are typically used for circuits up to 300V.

Glass Body Fuses

Instead of ceramic, tubular glass is used for constructing the plug fuse body in glass types. The fuse element wires are visible. Glass bodied plug fuses provide general purpose protection for lower voltage electronic and electrical circuits.

Blade Terminal Fuses

These plug fuses have blade type terminals at the ends that plug directly into equipment fuse clips, providing easy fuse replacement. Automotive fuses are a common example using this style.

Bolted Terminal Fuses

Bolted terminal cartridge fuses have threaded studs at the end that bolt into sockets on equipment or busbars. This style offers very secure physical and electrical connection.

Electronic Fuses

For protection of semiconductor devices and power electronics circuits, fast acting electronic fuses are available. These incorporate advanced fusible elements and filler for current limitation.

Important Ratings and Specifications

Voltage Ratings

Common voltage ratings for plug fuses are:

  • 125 or 250V AC/DC for electronic circuits
  • 600V AC for controls and lighting
  • 1000V or more for power circuits

Lower voltage fuses may be telecom/signal rated. DC rated fuses are also available.

Current Ratings

Plug fuses cover a wide range of current ratings, including:

  • 0.5A to 30A fuses for electronics
  • 6A to 60A for control circuits
  • 100A to 200A in power applications

The appropriate current rating depends on circuit load current and design margins.

Body Size Standards

International standard IEC 60127 defines the commonly used 5x20mm and 6.3x32mm plug fuse sizes. Regional standards like UL 248 also apply.

Fast Acting vs Time Delay

Fast acting fuses operate in less than 0.1 seconds, while time delay plug fuses take 0.1 to 10 seconds to respond depending on current overload. Faster fuses protect semiconductors, while time delay fuses are for motors.

Special Features

Some plug fuses offer built-in blown fuse indication contacts or LED indicators to allow remote monitoring. High rupture capacity and current limiting fuses are also available.

Advantages of Using Plug Fuses

Plug fuses offer various benefits that make them a versatile protection solution:

  • Compact cylindrical shape saves space
  • Quick and easy to insert or replace
  • No need for separate fuse holders
  • Wide range of ratings for flexible application
  • Protect against both overloads and short circuits
  • Inexpensive compared to alternatives
  • Easy to stock spares for frequent replacement

The simplicity and convenience of plug fuses makes circuit protection highly efficient.

Typical Applications

Plug fuses are very popular for the following applications:

  • Protecting controls, sensors, PLCs and other automation
  • Motor drives and controllers
  • Switchgear, distribution boxes and panelboards
  • Electronic power supplies and battery chargers
  • Battery powered portable equipment
  • LED drivers and ballasts
  • Semiconductor and power electronics circuits
  • Alarm and security systems
  • Telecom/radio equipment power supplies

Essentially, any application where limited space makes fuse holders impractical can benefit from plug fuses.

Installation Guidelines

Adhering to fuse manufacturer guidelines and electrical codes ensures safe and reliable installation:

  • Select fuse ratings based on equipment nameplate data
  • Use fast acting fuse for electronics, time delay for motors
  • Ensure fuse voltage equals or exceeds circuit voltage
  • Current rating should be 125-150% of full load
  • Insert fuses with correct orientation
  • Ensure secure clip-in or bolted mounting
  • Observe proper live and neutral connections
  • Provide local indication on blown fuses
  • Keep spare fuses stocked for quick replacement

This avoids issues like nuisance tripping or lack of protection during faults.

Troubleshooting Blown Fuses

Repeated blowing of plug fuses indicates an underlying issue that should be addressed:

  • Test fuse for continuity using a multimeter
  • Check for short circuits using insulation testers
  • Examine devices on circuit for damage
  • Measure operating current and compare with fuse rating
  • Rule out voltage fluctuations or transients
  • Replace with fuse of identical rating
  • Consider increasing fuse rating if undersized
  • Repair equipment faults or deratings that overload fuses

Identifying and correcting the root cause of fuse failure improves reliability.

GRL-plug fuse

GRL Fuse Range

GRL supplies an extensive range of fuses suitable for global requirements:

Product Catalogue Overview

  • Ceramic and glass body options
  • electronic, general purpose and power fuses
  • Blade and bolted terminal designs
  • Voltage up to 1500VAC
  • Sizes from 2A to 200A+
  • IEC, UL and BS approved fuses
  • Wide array of accessories

Diverse Ratings and Approvals

GRL fuses are certified for:

  • Electronic and semiconductor protection
  • Telecom/communication circuits
  • Industrial controls and automation
  • Power factor correction systems
  • Solar and UPS systems
  • LV and MV switchgear
  • Railway and marine applications

We have the right fuse for your specific needs.

OEM Capabilities

Private labeling, custom packaging and pre-installed fuses are available for OEM customers.

Global Availability

GRL supplies plug fuses worldwide through distribution partners in North America, Asia, Middle East, Europe and Africa regions.

GRL-electrical switchgear and control gear

Frequently Asked Questions

  1. What is a plug fuse?

A plug fuse is a compact, cylindrical cartridge fuse that can be directly plugged into equipment fuse holders or terminals for easy installation and replacement.

  1. What are the different types of plug fuses?

Common types are ceramic body, glass body, electronic, blade terminal and bolted terminal. Different body materials, terminal styles and ratings are available.

  1. What are the most common sizes for plug fuses?

The most widely used plug fuse sizes are 5x20mm and 6.3x32mm. Other sizes like 5x15mm or 10.3x38mm exist for specific applications.

  1. What are plug fuses used for?

Plug fuses provide overcurrent protection in control panels, motor controls, switchgear, electronics and other electrical equipment where space is limited.

  1. What is the voltage rating on plug fuses?

Typical plug fuse voltage ratings range from 32V for electronics up to 600VAC for power circuits and 1000V+ for special applications.

  1. How do you remove and replace plug fuses?

Plug fuses can be directly pulled out and inserted into equipment fuse clips or terminals. Power must be disconnected before fuse replacement.

  1. Can I use a higher rated plug fuse for replacement?

Replacement fuses must be identical rating to ensure proper protection. Using higher rated fuses can risk equipment damage from sustained overcurrents.

  1. How to tell if a plug fuse is blown?

A blown plug fuse will have a broken internal element visible through the fuse body. Absence of continuity when tested with a multimeter also indicates a blown fuse.

  1. Why do plug fuses blow?

Fuses blow from either a short circuit or sustained overload exceeding the fuse current rating. The root cause like a fault, derated insulation or undersized fuses must be corrected.

  1. What is the difference between fast-acting and time-delay plug fuses?

Fast acting fuses open in under 0.1 seconds, while time-delay fuses take 0.1 to 10 seconds to respond depending on overload level.

  1. How do I find the right replacement plug fuse?

Always replace with a fuse of identical voltage, current rating and size as the original. Refer equipment manual or fuse labeling for specifications.

  1. Can I use a plug fuse in a fuse holder?

If the fuse holder accepts cylindrical fuses and the ratings match, a plug fuse can physically fit and work electrically in a holder.

  1. What are ceramic body plug fuses?

Ceramic body fuses have a cylindrical body made from ceramic material that provides high dielectric strength for interrupting arcs during blows.

  1. How are glass body fuses different from ceramic ones?

Glass fuses have bodies made of tough, tubular glass instead of ceramic. They are more commonly used for lower voltage ratings than ceramic types.

  1. Are there waterproof plug fuses?

Yes, some plug fuses feature silicone rubber end caps and seals to prevent water ingress, for applications that require water resistance.

  1. Where can I buy plug fuses?

Plug fuses are widely available from electronics and electrical distributors, component retailers and direct from manufacturers like GRL.

  1. Who are the top plug fuse manufacturers?

Leading plug fuse brands include GRL, Littelfuse, Bel Fuse, Schurter, ETI, Mersen, SIBA and EFEN.

  1. What standards do plug fuses comply with?

Common standards include IEC 60127, UL 248 for low voltage fuses and EN/IEC 60269 for general purpose fuses.

  1. How do I properly install plug fuses?

Follow fuse orientation markings, ensure secure contact insertion into clips, tighten bolted studs properly and make connections as per wiring diagram.

  1. Is there an indicator that shows a plug fuse has blown?

Some plug fuses have blown fuse indication contacts or LEDs. Checking for continuity manually or remote monitoring can also identify blown fuses.

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