ETAP Question

[LT1982]

Any experienced Etap users here understand what the heck the problem is with this Star Auto-Eval?

Keeps saying "trip curve crosses" damage curve for a 20A breaker protecting 12awg cable.

thanks

Picture:

https://ibb.co/1656NXk

 

[dpc]

It is just seeing the cable damage curve being crossed by the breaker curve up in the instantaneous region. Ideally, the trip curve would be totally to the left or below the damage curve. For #12 AWG, and a 20 A (UL) breaker, it's not a concern, regardless of what the curves are showing.

 

[LT1982]

Thanks. I understand it is not a concern. Regardless, is there a way to remedy this?

I've gone thru many CB models in the library and can't find one with the inst. region to the left of the #12

How do you do this in your studies?

 

[dpc]

For wire this small, I would just delete the cable damage curve, unless there is some contractual requirement to show this. It's not common to be preparing TCCs for 20 A MCCBs. The system is NEC-compliant, and the breaker is probably non-adjustable. Just because the software can generate the TCC doesn't mean it provides any useful information.

 

[davidbeach]

How far down a #12 can you push 39kA anyhow? No worry about cable damage for faults on the cable, just for through faults.

I’ll see your silver lining and raise you two black clouds. - Protection Operations