Temp of Conductor

[scott minter]

Good Morning

I have noticed using EasyPower software the default setting for field temp of conductor is 50c.

In discussions with an engineer at our company he say E Tap defaults to 75c.

We have done some research and came across a GE white paper that says you should use 30c.

EasyPower has options all the way from 25c to 250c.

Depending on the setting it changes the resistance and and the indecent energy level.



My question is there a hard standard we should be using ?

Thank you for the help.

 

[Smart $]

Depends on whether you are referring to ambient temperature or conductor temperature while conducting. 30°C for ambient, 75°C maximum while conducting for general wiring.

 

[scott minter]

Not ambient.

The conductors operating temperature.

The issue being discussed is Arc flash assessments. One group is using E Tap and its default setting (75C).

I am using EasyPower and its default setting (50C).

Another engineer is using Mathcad and is entering (30C) with the rationale that the probability of and an Arc flash occurring
would happen when first energizing the circuit and the conductors would not be to operating temperature.
The panels in question are in an A/C building. I feel there is some validity to the 30C methodology.

When you play with the conductor temperature it yields different results.

Is there a strict rule governing what temperature to use ?

 

[Smart $]

Not ambient.

The conductors operating temperature.

The issue being discussed is Arc flash assessments. One group is using E Tap and its default setting (75C).

I am using EasyPower and its default setting (50C).

Another engineer is using Mathcad and is entering (30C) with the rationale that the probability of and an Arc flash occurring would happen when first energizing the circuit and the conductors would not be to operating temperature.
The panels in question are in an A/C building. I feel there is some validity to the 30C methodology.

When you play with the conductor temperature it yields different results.

Is there a strict rule governing what temperature to use ?

I agree. No strict rule AFAIK.

 

[scott minter]

Thank You for the help.