Cable termal constrait

[laumarher]

How to resolve that warning?:

"Cable termal constrait (i2t>k2s2) is exceded at 10 ms, please check if circuit breaker energy limitation curve validates k2s2<i2t for short circuit value, otherwise please increase cable cross section value oh [PH]"

I have tried increasing the cable section and it does not solve the problem.

I attach a file, thank you

[Manon_Chaboud]

Hello @laumarher, thank you for your post, we'll come back to you!

[Sumit_Kumar]

@Darini please have a look at it

[Darini · Accepted solution]

hi @laumarher  ,

thanks for the query!

this issue here is that Ecodial showed a “thermal constraint (I2t > k2S2) exceeded” warning for cables

This means that during a short-circuit, the energy passing through the cable (I2t) was higher than what the cable’s insulation and size could safely handle.

Reason:
The fault current at that point was around 12 kA, and the earlier cable size (1.5 – 10 sqmm) was too small to withstand that energy.

Workaround:
After increasing the cable size to 16 sqmm (Cu/PVC), the cable can now handle the short-circuit energy, and the warning is cleared.

so you might have tried to increase the CSA to 4 or 6sq.mm and that is not sufficient according to the constraints.

Hope that clarifies it for you!

Regards,

Darini H.D