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Modern test methods ensure the highest quality

Quality inspection of tools

Conductor pull-out test

Crimping points can be affected by tensile forces during wiring or operation. Therefore, properly crimped connectors and ferrules must offer a high degree of mechanical safety. To test the tensile load capacity, a crimped conductor is exposed to a predefined, cross-sectional tensile force for a period of 60 seconds, and it must withstand this load. The tensile force exerts stress on the conductor at the crimping point. Damage to the crimping point must not occur. Generally, even the maximum tensile force is tolerated, until the connection is destroyed.

Description Language Updated
Table for conductor pull-out force per cross section [PDF, 34 KB] english 25.03.2017

Gas tightness of crimp connections

View lengthways through the crimp  

View lengthways through the crimp

A gas-tight crimp connection is the result of a defined crimping process. The wire strands in one or more conductors and a connector are joined into a largely homogeneous structure with no gaps. This results in a permanent, reliable connection that cannot be detached.

View crosswise through the crimp  

View crosswise through the crimp

In addition to the mechanical and electrical properties to be tested, a visual examination of the crimp area provides important information regarding the quality of the connection. To this end, micrographs or images are captured by means of computer tomography. The porosity, elongation at break, and the deformation of the individual wire strands is assessed in this way.

When crimping is performed correctly, it is largely protected from gases such as industrial atmospheres that contain sulfur dioxide and from oxygen, salt spray or other corrosive media. This prevents gases causing corrosion on the individual wire strands during the lifetime of the connection and any resulting deterioration in the electrical properties.

The crimp connections of ferrules cannot be compared directly with connectors or cable lugs. They must be considered differently. Ferrules are used as splicing protection for class 2, 5, and 6 copper wires that are stranded, fine stranded, and extra finely stranded. The copper sleeve of the ferrule has a material thickness of just 0.15 to 0.45 mm. It is significantly thinner than that of cable lugs, for example. If the copper sleeve of a ferrule with a conductor cross section of 2.5 mm² has a material thickness of 0.3 mm, the material thickness of a comparable cable lug is 0.8 mm.



With respect to the crimping of ferrules, DIN 46228 (Part 1 - 4) describes the mechanical testing and overall dimension check starting from 2.5 mm² for class 5 copper wires according to IEC 60228. The electrical properties are evaluated in association with the later application, e.g., within a terminal block. Corrosion-free contact areas are a prerequisite for low-resistance and therefore high-performance connections, especially in aggressive environments. For this reason, the secure positioning of the connection in the terminal point must be ensured. The impact of aggressive media on the terminal point is evaluated in the terminal block standard for copper wires. The voltage drop according to DIN EN 60947-7-1 must not exceed a value of 3.2 mV before or after the test, nor must it exceed 1.5 times the value measured at the start of the test. The connection is deemed gas tight if the test object meets the requirements of a test in a condensation changing climate with an atmosphere that contains sulfur dioxide in accordance with DIN 50018 (AHT 2,0 S). This test involves storage in a condensation changing climate with changing humidity and temperatures. In the first test section, the test object is exposed to an SO2 volumetric concentration of 0.67% at a temperature of 40°C and humidity of approximately 100% for 8 hours. After this test, the test objects are left to dry for 16 hours with the door open. This cycle is performed twice, before the test objects are assessed.

When used correctly at contact points, Phoenix Contact crimping tools, ferrules, and connectors achieve a permanent gas-tight connection. Even aggressive media do not impact this connection.

1000 V tests in accordance with EN 60900

Apparatus for voltage tests performed on insulated hand tools in accordance with DIN EN 60900  

Apparatus for voltage tests performed on insulated hand tools in accordance with DIN EN 60900

In the strict safety regulations for working on live parts up to 1000 V AC and 1500 V DC, VDE-insulated tools perform a key role in addition to general safety measures.

International standard IEC 60900 places very stringent requirements on insulated tools. In addition to specifications regarding the geometry and dimensions, this standard primarily defines the properties of the insulation material. Comprehensive test specifications complete the standard. For example, the condition of the insulation and markings is visually inspected. An impact test checks the resistance of the insulation layer to impacts. Breakages, flaking or cracks must not occur, even at low temperatures (-25°C or -40°C depending on the category). Following an indentation test (semi-sphere 5 mm in diameter), a force of 20 N is applied to the insulation for 2 hours at 70°C. After cooling, the test point must not exhibit any electrical disruptive discharge, flashover or sparkover over a period of 3 minutes while a voltage of 5 kV is applied (r.m.s. value).

In dielectric tests, pre-conditioned tools (water bath/storage in humidity cabinet) undergo voltage testing. A voltage of 10 kV is applied for 3 minutes. The discharge current must be less than 1 mA per 200 mm coating length of the hand tool.

Marking on a VDE tool  

Marking on a VDE tool. The letter “C” indicates that it may be used at low temperatures.

Other tests that are performed assess the adhesive strength of the insulation coating, the markings' resistance to chemicals, and the combustion behavior. If the tool successfully passes type testing, this provides the basis for using the VDE logo in conjunction with IEC 60900. Regular inspections of production sites and test centers are also made by the appropriate VDE approval body. Among other things, this involves taking random product samples from ongoing production and assessing them. The manufacturer already carries out comprehensive testing during the production stage, ensuring full compliance with the requirements of IEC 60900. The last hurdle is the test for electric strength. Each tool is tested at 10,000 V AC. Only after passing this test can a tool be referred to as VDE-certified and released for sale. VDE-insulated tools from Phoenix Contact, which are marketed accordingly, provide the user with a high degree of quality and maximum possible safety when working with live parts up to 1000 V AC and 1500 V DC.

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General information
Cutting, stripping, and crimping
Material properties and use


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