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10.10 Verification of Temperature Rise

Next – Drawings >> – Verification of the Complete Assembly

This clause tests the assembly as a whole with a Rated Diversity Factor (RDF) of 1 and the incoming and outgoing circuits are loaded at their rated current. If the sum of the outgoing circuits is greater than the incoming circuit, the outgoing circuits can be grouped together to match the value of the incomer. The groups are selected in the most unfavourable position to determine the most arduous conditions and tests will be undertaken to include all functional units in at least one group. – Verification Considering Individual Functional Units Separately and the Complete Assembly

This clause tests the individual functional units (based on Clause and an assembly test with a specific RDF requested by the manufacturer. For example a 1200A outgoing unit at 0.9 RDF will be as follows:

1200A x 0.9 RDF = 1080A test current

As with Clause, if the sum of outgoing circuits is greater than the incoming circuit, the outgoing circuits can be grouped together as above. a) – d) – Verification Considering Individual Functional Units and the Main and Distribution Busbars Separately as well as the Complete Assembly

This clause is split into 4 sub-sections;

a) Main busbars
b) Distribution busbars
c) Individual functional units
d) Complete assembly

Depending on your requirements, all tests or a combination of the above can be performed.

Temperature Rise Options

Temperature Rise Options

With all temperature rise tests, if the outgoing circuit load is less than the incoming circuit load, the remaining current will be distributed via another appropriate circuit (current drain). Further RDF information can be found in Annex E of IEC 61439-1.

View this PDF to find out more about advantages and disadvanatges of testing to the three clauses.



Temperature Rise Limits

During temperature rise tests, the limits set in Table 6 are applied in a 35°C ambient. It is likely that the assembly will include other components where the manufacturer specifies an operating temperature limit; the operating temperature rise limits are essential for performing a temperature rise test. A copy of each component manufacturers’ data sheet shall be supplied to kA Testing for verification.

Testing based on a 50°C ambient requires the temperature rise limits to be adjusted to suit the higher temperature. An example is shown below for a component with a 120°C maximum operating limit:

Maximum operating temperature – ambient = temperature rise limit

120°C maximum operating temperature – 35°C ambient = 85K temperature rise limit

120°C maximum operating temperature – 50°C ambient = 70K temperature rise limit


temperature rise testing

Test Requirements

Temperature rise test are conducted at 50Hz but we can test at 60Hz if required. Adequate test cable access and test cable connection points must available; this includes removable access side plates on sub main distribution boards. If the incoming and/or outgoing connection points are busbars, the hole patterns required for kA Testing Facility to connect onto are available on this drawing and can be advised given rated currents.

Where copper bar test connections have to pass through panel outer covers these are removed and replaced with replica cardboard covers with cut-outs for the copper bars. Should you require these covers to be the same material as the original covers spare covers should be supplied with cut-outs allowing adequate clearance for the test connections to pass through.

Before connecting test cables/coppers we shall be provided with the rated currents for the incoming and outgoing circuits, as the connections fitted are determined by the standard based on this information. If you require main busbar test to verify the busbar rating (, the standard requires busbars within your panel to be 2m long and include a minimum of one joint if the panel is extendable.

Before performing the temperature-rise test we require limits of temperature-rise that are not covered by Table 6 of the standard. We have a Temperature Rise Limit Form available to fill in all of the component details, which should be supplied with the data sheets for the products.

The test connections will be fitted in line with Tables 11 & 12; if the section does not achieve the rated current and is derated during the test the existing cables can used. However if the cable is larger than Tables 11 & 12, they shall be recorded as “specified by the client” in the certificate. If the correct test connections must be used as per Tables 11 & 12, the connections can be changed and a retest performed (possibly at additional cost).


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