10.2 Strength of Materials and Parts

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Clause 10.2 is to establish the strength of the construction materials and parts of the assembly considering mechanical, thermal and electrical capabilities. Click on headings below to find out more about the sub-clauses:

Resistance to Corrosion

Verification of Insulating Materials to Abnormal Heat and Fire

Lifting

Mechanical Impact

Marking

10.2.2 Resistance to Corrosion

This clause is to verify the resistance to corrosion of representative samples of ferrous metallic enclosures including internal and external ferrous metalic constructional parts of the assembly.

We normally perform severity test A for Indoor enclosures and for this you will need to supply a representative enclosure with door assembly, including hinges and catches etc., maximum size 500 x 500 x 200mm deep, with a few loose metal parts (nuts, fixing bolts and threaded rod).

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10.2.3.2 Verification of Insulating Materials to Abnormal Heat and Fire

Clause 10.2.3.2 is to verify the suitability of the materials used on an assembly with the glow-wire test principles of IEC 60695-2-10 and the details given in IEC 60695-2-11.

The glow wire tip (see below for test temperatures) is applied to the material sample for 30 seconds and measured for ignition time, time for the sample to extinguish, flame height, critical observations and non-critical observations.

The temperature of the glow wire tip is as follows:

• 960°C for parts necessary to retain current-carrying parts in position
• 650°C for all other parts, including parts necessary to retain the protective conductor

At kA Testing Facility we request that a sample of each insulating part is sent with the assembly where glow-wire testing is required.

Watch glow wire video here.

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10.2.5 Lifting

lifting testEach assembly with provision for lifting will be subject to a lifting test.

The assembly is lifted with 1.25 times the shipping weight in a series of tests involving raising the assembly and moving it smoothly along vertical and horizontal planes. If the assembly has more than one shipping section, each section will be tested individually. During the test the assembly is checked for deflections. After the test the assembly is checked for signs of cracks and other permanent distortions.

Details of lifting information such as eye bolts, lifting bars, shipping sections etc. shall be detailed in the drawings of the assembly.

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10.2.6 Mechanical Impact

Mechanical Impact (IK) testing is performed in accordance with IEC 62208 as stated in IEC 61439-2. The IK rating is determined by the effect of a striking object on an assembly enclosure from a given distance from the assembly.

IK testing is not mandatory for a full certificate of verification tests.

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10.2.7 Marking

Designation label

Designation label

The test applies to the Assembly designation label, the information required for the label can be found in Clause 6.1.

Marking that has not been made by moulding, pressing, engraving or a similar method will be subject to the marking test.

It is preferred that a sample label is supplied to kA Testing Facility for marking verification. All labels shall be supplied for inspection although not necessarily subjected to the physical test.

 

 

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