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An example of marking according to IEC/EN 60079 is "Ex ib IIC T4". My question is about the temperature classes.
T1 450 °C
T2 300 °C
T3 200 °C
T4 135 °C
T5 100 °C
T6 85 °C
Suppose an transmitter is certified as T4. Now, what does this mean? I and my colleague have 2 opposing interpretations.
1) I argue that it specifies the maximum temperature that the surface of the transmitter could reach under normal/abnormal conditions. So, by this logic, T5 is better than T4 and T6 is better than T5.
2) My colleague argues that it specifies the maximum surface temperature from outside that the transmitter can withstand without going haywire. So, by this logic, T5 is better than T6 and T4 is better than T5.
So, which one is correct?
T1 450 °C
T2 300 °C
T3 200 °C
T4 135 °C
T5 100 °C
T6 85 °C
Suppose an transmitter is certified as T4. Now, what does this mean? I and my colleague have 2 opposing interpretations.
1) I argue that it specifies the maximum temperature that the surface of the transmitter could reach under normal/abnormal conditions. So, by this logic, T5 is better than T4 and T6 is better than T5.
2) My colleague argues that it specifies the maximum surface temperature from outside that the transmitter can withstand without going haywire. So, by this logic, T5 is better than T6 and T4 is better than T5.
So, which one is correct?