How to choose ferrules and the right crimping tool
Wire-end ferrules bundle fine-stranded conductors into a firm, gas-tight end that seats cleanly in a terminal. This guide shows how to match ferrule and crimping tool to the cross-section and standard DIN 46228 and how to crimp conductor ends without faults.
View ferrulesInhalt
Why use a ferrule at all?
A wire-end ferrule gathers the individual strands of a fine-stranded conductor into a firm, shape-stable end. That lets the conductor enter a screw or spring terminal cleanly, without stray strands sticking out and causing a short or a poor contact area.
The crimped ferrule provides a durably low contact resistance and prevents so-called cold flow of the copper under the terminal pressure. Without a ferrule a screw terminal can loosen over time as the strands settle.
- Protects the strands against fraying and single-wire breakage.
- Ensures a gas-tight, corrosion-resistant contact.
- Prevents the terminal loosening as the conductor settles.
- Colour code to DIN 46228‑4 makes cross-section matching easy.
Which ferrule fits which cross-section?
The decisive factors are nominal cross-section and barrel length. The ferrule must take the conductor exactly: too large and it will not crimp cleanly, too small and the strands will not fit. Insulated ferrules to DIN 46228‑4 carry a coloured plastic collar whose colour indicates the cross-section.
- Standard ferrule: one conductor per ferrule for most terminals.
- Twin ferrule (TWIN): crimp two equal conductors together, e.g. looped bridges.
- Long version for deep terminals or DIN-rail terminal blocks in the cabinet.
- Tinned copper ferrule for reliable contact and corrosion protection.
Which crimping tool crimps to standard?
The press tool decides the quality. A ratchet mechanism with a locking device is essential: it only releases the tool once full crimp force is reached, guaranteeing a reproducible crimp. Freehand pliers without a lock give inconsistent results.
The main crimp profiles are square (four-indent) and hexagonal, plus the trapezoidal form. Square and hex profiles compress all around and suit a wide cross-section range; they can be inserted from either side, which speeds up work.
- Ratchet with locking device for constant crimp force.
- Self-adjusting or with position selection by cross-section.
- Front or side entry depending on the workspace.
- For series work an automatic strip-and-crimp unit pays off.
How do you spot a good crimp?
A correct crimp is compressed evenly, with no split collar and no stray strands sticking out. The conductor must reach the plastic collar, and only a minimal wire overhang should show at the end. A pull test confirms the joint holds.
- Wrong cross-section: ferrule too large - loose crimp, high resistance.
- Stripped too short - strands do not reach fully into the barrel.
- Wrong crimp nest chosen - over- or under-crimped.
- Worn jaws - untidy, uneven form.
Frequently asked questions
Do I always have to fit ferrules on fine-stranded conductors?
In most screw terminals yes, unless the manufacturer explicitly allows otherwise. The ferrule prevents fraying and settling of the strands and secures a durably low contact resistance.
Which crimping tool for 0.5 to 2.5 mm²?
A ratchet tool with a square or trapezoidal profile for roughly 0.14 to 6 mm² covers these standard sections. A locking device for reproducible crimp force is essential.
Square or hexagonal crimp?
Square suits small to medium cross-sections up to about 6 mm² and is side-independent. Hexagonal delivers the higher crimp force for large conductors from 10 mm² up to 50 mm².
How far should I strip the insulation?
Far enough for the strands to reach flush up to the plastic collar - usually barrel length plus about 1 mm, so roughly 8 to 12 mm depending on the ferrule.
Looking for ferrules and a crimping tool?
We supply insulated and bare wire-end ferrules to DIN 46228 plus matching ratchet crimping tools with a locking device - from assortment cases to series solutions.
Standard-compliant
Ferrules to DIN 46228, colour code per Part 4.
Reproducible
Crimping tools with a locking device for equal force.
Full assortment
Cross-sections from 0.14 to 50 mm² from stock.
Expert advice
Our team helps you pick tool and ferrule.