Rated Conductor Temperatures for Insulation Types

This table outlines the temperature ratings for different insulation materials commonly used in electrical systems. The parameters include:
- Maximum Voltage Class (kV): The voltage level for which the insulation type is rated.
- Maximum Operating Temperature (°C): The highest temperature the conductor can sustain under normal operating conditions.
- Maximum Overload Temperature (°C): The temperature limit during temporary overload conditions (e.g., 100 hours/year).
- Maximum Short-Circuit Temperature (°C): The temperature a conductor can withstand during a short-circuit event.

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Summary of Insulation Types and Ratings:

Insulation Type	Maximum Voltage Class (kV)	Maximum Operating Temperature (°C)	Maximum Overload Temperature (°C)	Maximum Short-Circuit Temperature (°C)
Paper (solid-type) multicore and shielded single conductor	9–69	80–95	110–115	200
Varnished cambric	5–28	72–85	85–100	200
Polyethylene (natural)	5–35	75	95	150
SBR Rubber	2–35	75	95	200
Butyl Rubber	5–35	85–90	100–105	200
Oil-Base Rubber	35	90	105	200
Polyethylene (crosslinked)	35	90	130	250
EPR Rubber	35	90	130	250
Chlorosulfonated Polyethylene	5	90	105	200
Polyvinyl Chloride (PVC)	2	70	105	160
Silicone Rubber	5	125	150	200
Ethylene Tetrafluoroethylene (ETFE)	2	150	200	250

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Key Insights:
1. Paper Insulation: Commonly used for high-voltage systems; can withstand temperatures up to 200°C under short-circuit conditions.
2. Crosslinked Polyethylene (XLPE): Known for its excellent thermal resistance, making it suitable for up to 250°C during short circuits.
3. Silicone Rubber: Highly flexible and capable of sustaining high temperatures (up to 125°C during operation).
4. Ethylene Tetrafluoroethylene (ETFE): Offers superior performance under extreme conditions, with a maximum short-circuit temperature of 250°C.

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Usage Notes:
- Short-circuit temperatures should not exceed the specified limits for more than a few seconds to avoid permanent damage.
- Overload periods exceeding 100 hours/year are not recommended for most insulation types.
- Always refer to national standards (e.g., IEEE, IEC, or NBR) for precise application guidelines.