IEC 61300-2-27:2024 determines the effects of dust on fibre optic interconnecting devices or passive components. This second edition cancels and replaces the first edition published in 1995. This edition constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous edition:a) normative references have been added;b) the relative humidity requirement during the test has been modified;c) the procedure description has been modified;d) Figure 1 showing possible test configurations has been added;e) the severity of the test has been updated according to the component and performance category;f) Clause 8 has been added, listing details to be specified and reported.