IEC TS 60695-2-20:2021

IEC TS 60695-2-20:2021 describes a test method that applies to solid electrical insulating materials of which test specimens can be provided. The test measures the time required to ignite a test specimen when it is affected by heat from an electrically heated wire wound around the test specimen. If the test specimen drips, the time at which this occurs is also recorded.
The test method can be used to provide classifications which can be used for quality assurance, the preselection of materials of products as described in IEC 60695-1-30, or to verify the required minimum classification of materials used in end products.
This basic safety publication is intended for use by technical committees in the preparation of standards in accordance with the principles laid down in IEC Guide 104 and ISO/IEC Guide 51.
One of the responsibilities of a technical committee is, wherever applicable, to make use of basic safety publications in the preparation of its publications. The requirements, test methods or test conditions of this basic safety publication will not apply unless specifically referred to or included in the relevant publications.
This third edition of IEC TS 60695-2-20 cancels and replaces the second edition of IEC TS 60695-2-20 published in 2004. This edition constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous edition:
– Contents page added
– Updated Scope (Clause 1)
– Updated Terms and Definitions, added new relevant terms (Clause 3)
– Updated Principle (Clause 4)
– Updated Apparatus (Clause 5; recommendation to change the power source from a.c. to d.c. with a constant current output. Reason for this recommendation: d.c. technology is easier to obtain and to handle, which has been found to improve the Repeatability and Reproducibility of the test.
– Updated Test specimen dimensions (6.2)
– Revised Test procedure (Clause 8)
– Revised Observations and measurements (Clause 9)
– Revised Evaluation of test results (Clause 10)
– Revised Test report (Clause 11)
– Revised Annex A: Deletion of conformational test; Guidance on verification of the heater wire winding before testing
– Addition of normative Annex B: HWCT PLC Classes
– Addition of informative Annex C: Calibration curve to determine test current (Ic) in a spreadsheet program
– Addition of informative Annex D: Precision data
It has the status of a basic safety publication in accordance with IEC Guide 104 and ISO/IEC Guide 51.
This basic safety publication is intended for use by technical committees in the preparation of standards in accordance with the principles laid down in IEC Guide 104 and ISO/IEC Guide 51.