Last edit: 27/08/2024
IEC 60204-1 indicates that a Voltage Test may be done on all electrical equipment, unless there is a fear that they cannot withstand the test, without damages.
The test is not compulsory and the decision whether to do it or not and on which components, is left to the Machinery manufacturer.
[EN 60204-1: 2018] – 18.4 Voltage tests
The test voltage shall be at a nominal frequency of 50 Hz or 60 Hz. […]
The maximum test voltage shall have a value of twice the rated supply voltage of the equipment or 1 000 V, whichever is the greater. The maximum test voltage shall be applied between the power circuit conductors and the protective bonding circuit for at least 1 s. The requirements are satisfied if no disruptive discharge occurs.
Components and devices that are not rated to withstand the test voltage and surge protection devices which are likely to operate during the test shall be disconnected during testing. Components and devices that have been voltage tested in accordance with their product standards may be disconnected during testing.
Therefore, it can be done on the field cables, for example, if we think that by laying them we may have damaged their insulation.
In general, we recommend to always do a Voltage Test of each Control Panel, following the indication given in IEC 61439-1. The test is better known as Dielectric Test.
[EN 61439-1:2021] 10.9 Dielectric properties – 10.9.1 General
For this test, all the electrical equipment of the assembly shall be connected, except those items of apparatus which, according to the relevant specifications, are designed for a lower test voltage; current-consuming apparatus (e.g. windings, measuring instruments, voltage surge suppression devices) in which the application of the test voltage would cause the flow of a current, shall be disconnected. Such apparatus shall be disconnected at one of their terminals unless they are not designed to withstand the full test voltage, in which case all terminals may be disconnected.
For panels at 400 Vac, the test has to be done at a voltage of 1890 Vac between each incoming phase and the earth terminal: 3 measurements in total. The test passes if there is no “disruptive discharge” during the test. It is not required the test to last for 60 seconds: a few seconds are enough.
