This week’s question is Part Two of last weeks’ question about trust/confidence in circuit breakers operating as expected when it comes to an arc flash. Last week was about older circuit breakers (older than 20 years).

This week’s question is about NEWER low voltage circuit breakers. Again, NEW is probably a relative term but let’s think of new as less than 20 years old. (I still think “New� music is anything from the 1990’s or later )

As stated in last week’s Question of the Week, the duration of an arc flash is generally considered to be based on the clearing time of an upstream protective device. The incident energy is directly proportional to the arc duration. Typically, the device’s time-current curve is used to determine the clearing time as part of an arc flash study and is frequently taken as absolute.

Of course, it is also based on condition of maintenance – feel free to comment about this issue or anything else you may think of.

Here is this week’s question:

What is your confidence that a NEWER Low Voltage circuit breaker’s clearing time will be as predicted?
-High Confidence
-Moderate/Reasonable Confidence
-Low Level of Confidence
-Not at all