4 ms·
Looking at the curves published here[1], no breaker should trip with a current draw under its rating, the tolerance goes the other way. For example, after 1h, a
by GuB-42 2y ago
Looking at the curves published here[1], no breaker should trip with a current draw under its rating, the tolerance goes the other way. For example, after 1h, at 30°C, a breaker should not trip if the current is less than 113% of its rating, and it should trip if it is more than 145%.
[1] https://www.tekdok.dk/files/CA908024E_Trip_curve_2021.pdf https://www.tekdok.dk/files/CA908024E_Trip_curve_2021.pdf
- nullc 2y agoInteresting, I've certainly had nuisance trips at <100% looking at https://www.ece.uprm.edu/~lorama/Square%20D%20CB%20Curves.pdf https://www.ece.uprm.edu/~lorama/Square%20D%20CB%20Curves.pd... page 36 you can see even at the rated 25c ambient it goes below 1 (though not as low as 0.9, much less 0.8 rule of thumb). I haven't given it a lot of research because NEC requires 125% (1/.8) for continuous loads (for conductor protection). Perhaps my experience was hot ambient/panel.