Looks to me if the fault was at Bus 36, the cable would only see 1.3 kA fault current and would be OK. Now if the fault was in the cable it could see more, but at that point the cable is damaged already so would it matter?
What if the fault were in the beginning of the cable run vs the end. Then the fault current will be a lot higher than 1.313kA. It might be closer to the 39kA. Then the tripping by the upstream breaker will not prevent the cable from seeing currents beyond their damage curve.
I think the problem is that there is too much fault current for #12 wire. Options: increase wire size or decrease Fault Current.
You cannot post new topics in this forum You cannot reply to topics in this forum You cannot edit your posts in this forum You cannot delete your posts in this forum You cannot post attachments in this forum