The "Final Temperature" is strictly limited by the insulation material. Common limits defined within IEC standards referenced by IEC 60949 include:
| Insulation Type | Limiting Temperature ($^\circ C$) | | :--- | :--- | | PVC (Polyvinyl Chloride) | 160 | | XLPE (Cross-linked Polyethylene) | 250 | | EPR (Ethylene Propylene Rubber) | 250 | | Paper Insulated (Oil-filled) | Depends on voltage |
Note: $\theta_i$ is typically calculated based on the operating temperature of the cable prior to the fault, often assumed to be the maximum conductor operating temperature (e.g., 90°C for XLPE). iec 949 pdf work
Some manufacturer websites (Prysmian, Nexans, Southwire) offer free non-adiabatic calculation tools. However, verify they follow IEC 60949 explicitly.
From the cable manufacturer’s datasheet (often a PDF), extract: The "Final Temperature" is strictly limited by the
The phrase "IEC 949 pdf work" highlights a modern reality: engineers rarely work from paper copies anymore. The official PDF of the standard is a protected, high-value document that allows for precise searchability. The "work" involved includes:
Plug everything into the main formula. Compare the result to your system’s prospective short-circuit current. If ( I_permissible > I_prospective ), the cable is safe. However, verify they follow IEC 60949 explicitly
The $K$ factor is crucial as it aggregates the thermal properties of the conductor material. It is defined by the standard as:
$$ K = \sqrt\fracQ_c (\beta + 20)\rho_20 \ln \left( \frac\beta + \theta_f\beta + \theta_i \right) $$
Where: