mpparent wrote:
As long as the breaker is sized to protect the cable/wire per NEC or other standard, it is ok. This is for low voltage (<=600V). Typically, cable damage curves are not plotted on TCCs for LV circuits given the prior statement.
As far as MV and HV systems: it's a good idea to plot the cable damage curves and seeing how they perform w/ the OCPD since you are dealing w/ a considerable amount of I^2R heating.
Mike
Mike, do you know why EasyPower does this? Do you know if SKM does the same thing?
Conversely, I ran into a situation recently where EasyPower's AutoCoordination feature recommended setting the LT settings on two 250A-300A MCCBs to a current level greater than the wire's rating. One of the instances it included a notification that doing so would exceed the rating of the wire, but the other one did not. I know any auto-features need a human to doublecheck the findings, but programs like EasyPower and SKM are using complicated calculations; it seems bizarre to me that it would get that wrong.