The Littelfuse wire harnesses are especially designed and manufactured for overload and heat protection. It keeps trucks, cars, boats and machines running without any errors. The materials used in it are premium quality.

The wire harness is the backbone of any electrical system. It keeps the wires all in one nice bundle so nothing gets tangled or broken. Every circuit is protected from damage by the power of Littelfuse products at the heart of this bundle. If there’s a power spike or a short, the fuse is the first thing to break the flow. That saves the wires, the battery, and the entire mechanism behind them. For more than 90 years, Littelfuse companies have been building that trust around the world. Engineers use these fuses because they always work the same way. Design, testing and quality checks are directed from Littelfuse’s headquarters in Chicago worldwide. All components are engineered for extreme heat, vibration and moisture. That’s why a littelfuse wire harness stands out in cars and boats and factories.

ATOF ® Automotive Blade Fuse

MINI® 32V Fast-Acting Automotive Blade Fuse

MICRO2® 32V Blade Fuse

Micro3

Low-Profile MINI® 58V Blade Fuse

MAXI Blade Fuse

Aftermarket - 297 Series - MINI® Fast-Acting Automotive Blade Fuse Smart Glow

Aftermarket - 257 Series - ATO® Fast-Acting Automotive Blade Fuse Smart Glow

Little parts do a lot, even in small spaces. Mini Inline Fuse Holder The compact design is perfect for tight wiring runs. It holds a littelfuse mini fuse tight no loose wobble. Rain, dust and road grime can’t touch the fuse inside. This keeps the connection dry and the current flowing year-round. Ideal for motorcycles, ATVs and small accessory circuits. The compact shell is resistant to cracking in cold winter months. Replacing a blown fuse requires no tools and takes seconds. The wire leads are already stripped for quick connection. This littelfuse inline fuse holder shows that big protection comes in small parts.
Medium fuse holders are positioned in between the small and heavy-duty types. They manage moderate loads found in car audio, lighting and water pumps. The shell is made of tough plastic that shrugs off heat. Inside, the fuse blade is held by brass contacts with a firm, even pressure. This maintains low resistance throughout the joint and prevents sparking. A medium holder usually has a clear cover to view the fuse. You can see its status in seconds, no guessing around. Littelfuse relay harness setups in daily driver cars A lot of people buy this size. It is a reliable bridge between light accessories and full power circuits.
Large fuse holders protect the largest loads in a vehicle or boat. Winches, inverters and thick battery cables require much strength. The housing is thick and water, oil and dirt proof. Bolt-style terminals keep the large-gauge wire from slipping over time. This design can fit high-amp fuses used in trucks and marine rigs. Low heat build up under continuous heavy current draw. A tight seal prevents corrosion of the metal contacts inside. This size is trusted for off-road rigs and commercial fleet vehicles. Works great as part of a complete littelfuse wire harness kit. Built tough. Built safe. Built for the toughest jobs on the road.

A new accessory doesn't need to mean ripping out the entire car's wiring. With this fuse tap you can add power without messing with the wiring in the fuse box. Just plug it into an existing fuse in the panel. It draws clean power to power lights, cameras or a phone charger. A real littelfuse mini fuse is included in the design for reliable protection at all times. This easy install involves no cutting, splicing or soldering. Designed to fit the standard mini fuse slots found in most modern vehicles. This keeps the original circuit completely intact and fully protected. DIY fans love how fast and clean this upgrade is.

Water and electricity don’t mix well, especially in outdoor vehicles. Littelfuse wire harness solves that problem with a fully sealed rubber boot. Littelfuse waterproof fuse connections stay dry in heavy rain or mud. The seal also blocks dust, salt spray and grime from the engine bay. This makes it ideal for trucks, boats and off-road builds. Corrosion can’t seep in and weaken internal metal contacts. The harness uses marine-grade wire, which won’t crack in sunlight. Installers secure it via a simple twist-lock design. It withstands vibration, bumps and rough terrain. Trusted choice for all wiring work in any weather.

Some builds require power to many circuits at once. This assembly gives several fused outputs from one input wire. Each slot has its own fuse, so one blown fuse does not affect the rest. Works great for littelfuse pdm wiring setups in custom builds and race cars. Circuit tracing is fast and simple with block labels. The block is easy to mount with two or three screws. Heavy gauge input wire distributes even power to all outputs. This provides a low voltage drop, even when the circuit is fully loaded. Builders use this in campers, boats and off grid solar systems. One block, many circuits, full control of your power system.

Mechanics rely on a reliable Littelfuse wire harness for their day-to-day repairs. Replacing the fuse quickly minimizes customer downtime. Clean wiring builds trust with every job performed. Littelfuse is why shops select consistent, proven results.

Salt water is hard on wiring and metal parts. A littelfuse waterproof fuse holder keeps boats running safely. Less dock-side repairs equals corrosion resistance. For trips out on the ocean, boaters rely on sealed harnesses.

Dust, mud and heavy vibration test every wire. Rugged Littelfuse wire harnesss protect tractors, ATVs and farm equipment. Rugged terminals, designed to endure harsh field conditions. Farmers need wiring that doesn’t fail in the middle of a season.

Campers need power for lights, fridges, pumps. A solid littelfuse fuse block handles many circuits at once. Safe nights on the road are a result of clean wiring. Simple, organized power systems are important to RV owners.

Solar needs a stable, protected power flow for installations. Fuse holders protect the battery from sudden surges. Sun and storm keep off-grid systems safe. Clean energy needs clean, safe wiring too.

Factories, telecom towers work day and night, 24/7. A reliable Littelfuse PDM wiring scheme handles multiple loads simultaneously. Reliability of fuses is paramount as downtime costs money. Proven, tested protection trusted by industrial teams every shift



A crimp joint is pure mechanical force. No solder or glue.
The right crimp shape folds metal tightly around each strand of wire.
Bad crimps leave air gaps that quickly increase electrical current resistance.
Higher resistance builds up more heat at the joint over time.
A circuit can fail due to too much heat melting the insulation.
A good crimp tool applies even pressure the length of the terminal.
This creates a gas-tight seal that prevents air and moisture from entering.
Tight, gas-tight couplings withstand corrosion better than twisted ones.
Pull-force tests make sure each crimp meets strength standards.
QL-Custom Technology Ltd tests each crimp before shipping it to you.
Good crimp geometry is the unsung hero of every safe Littelfuse wire harness.



The fuse holders arrived fast and fit perfectly on my truck build. Clean crimps, no loose connections at all. Will order again for my next project.

I needed a waterproof Littelfuse wire harness for my boat wiring. This held up great through two months of heavy rain and salt spray.

Our shop orders these in bulk for customer repairs. Consistent quality every single time we order. Great support team as well.

The fuse tap harness let me add a dash cam without touching my main wiring. Super simple and worked on the first try.

Used the 24V relay harness for our fleet trucks. No failures after six months of daily heavy use. Impressed with the durability.

Great customer service when I had questions about fuse ratings. They helped me pick the right size fast. Order arrived quickly too.


Wiring parts should never be a gamble to purchase. QL-Custom Technology Ltd. eliminates that risk with harness solutions that are tried, tested and sealed. All Littelfuse wire harnesses are strictly crimped and sealed checked before the shipment. We carry a complete line of holders, blocks and fuses from small Littelfuse mini fuses to large heavy duty fuse holders. Having trouble finding the right part? We study the Littelfuse wire harness manual so you don’t have to guess. We know Littelfuse semiconductor technology and how it protects your circuits from surges and heat. “We are trusted partners in the wiring world and we bring real engineering knowledge to every order. Whether you need one holder or a full fleet order, we deliver fast, accurate, and ready to install.