Paul, I fully endorse that attitude. I had the situation, many years ago now, where a computer calculation of short circuits was submitted for my approval using a software package from a major international electrical engineering company. The output didn't quite look right to me (despite having seen a number of satisfactory submissions using this package previously) so I did the calculations as per the standard. Still wrong! I then looked at the difference in the computer's answer and my answer from the same input, and on a hunch changed a '+' to a '-' in one of the equations - which then gave me the same answer as the computer. They had coded the equation incorrectly and not properly verified the output, yet people were using this to set up their protection scheme. I have to confess I felt a bit smug telling them of their problem.....

Paul, I fully endorse that attitude. I had the situation, many years ago now, where a computer calculation of short circuits was submitted for my approval using a software package from a major international electrical engineering company. The output didn't quite look right to me (despite having seen a number of satisfactory submissions using this package previously) so I did the calculations as per the standard. Still wrong! I then looked at the difference in the computer's answer and my answer from the same input, and on a hunch changed a '+' to a '-' in one of the equations - which then gave me the same answer as the computer. They had coded the equation incorrectly and not properly verified the output, yet people were using this to set up their protection scheme. I have to confess I felt a bit smug telling them of their problem.....