The method applies to enclosures with no ventilation, or enclosures with natural ventilation openings (louvers) of known dimensions.
Certification bodies (such as UL, CSA, VDE, or TÜV) accept the TR 60890 method as a valid verification route for assemblies built according to IEC 61439. Auditors will expect to see the calculation sheets.
Not suitable for highly compartmentalized forms of separation (e.g., Form 4b).
Because it is a Technical Report rather than a full International Standard, IEC TR 60890 provides guidance and recommendations, giving manufacturers and designers some flexibility in applying the method. Nonetheless, it is widely recognized as a key reference in the industry. iec tr 60890 pdf
While IEC 61439 is the main standard governing low-voltage switchgear design, it explicitly references IEC TR 60890 as a valid alternative to physical testing for specific enclosure configurations (typically up to 1600 A).
You calculate the effective heat-dissipating surface area of the enclosure (in m²). For free-standing cabinets, you consider all six sides. For wall-mounted panels, the wall-mounted side is excluded.
Avoid these errors that engineers frequently make when applying the PDF: The method applies to enclosures with no ventilation,
To achieve certification under the IEC 61439 series, designers must verify temperature rise. Using the calculations from IEC TR 60890 satisfies the verification requirements for a vast majority of standard commercial and industrial distribution boards. Preventing Equipment Derating
is the go-to technical report for verifying air temperature-rise inside enclosures through calculation. By using this method, manufacturers can ensure safety and reliability without always needing expensive and time-consuming physical tests. What is IEC TR 60890?
The IEC TR 60890 method simplifies complex thermal dynamics into a manageable calculation process. 1. Calculation Principle While IEC 61439 is the main standard governing
The method considers only and does not apply to forced‑ventilated enclosures. It is intended to determine the temperature rise of the air inside the enclosure , which can then be used to estimate the temperature of individual components.
Engineers can validate design modifications instantly on a spreadsheet or simulation software rather than waiting weeks for a laboratory slot.
: Surface area, material, and the presence or absence of ventilation openings.
The calculation method is highly valued because it allows manufacturers to verify custom assemblies (like a specific switchboard built for a single project) without destroying a unit in a test lab.