Dealing with NEC 240.87

[Cartoon1]

I'm adding a square d type breaker for a 1200A service to meet NEC 240.87 Arc energy reduction. From my understanding is that the instantaneous breaker setting need to be lower than the available bolted fault. The available fault at this service location is 12,000A. In the picture attached i modified the instantaneous setting to trip below than 12,000A. I want to make sure if this is meeting NEC 240.87 and i did it the right way. Thank you,

 

[mayanees]

No sir, it needs to be set for the arcing fault current:
240.87 (A) Documentation.
Documentation shall be available to those authorized to design, install, operate, or inspect the installation as to the location of the circuit breaker(s). Documentation shall also be provided to demonstrate that the method chosen to reduce clearing time is set to operate at a value below the available arcing current.
The arcing current in systems below 1000 Volts is typically around 55% of the bolted fault current.
As far as documentation goes, I would use SKM to provide the calculation.
You would think this would means loads of opportunity for anyone with a power systems analysis package, but it's like anything else with arc flash, it has to be enforced by an AHJ.

 

[Cartoon1]

No sir, it needs to be set for the arcing fault current:
240.87 (A) Documentation.
Documentation shall be available to those authorized to design, install, operate, or inspect the installation as to the location of the circuit breaker(s). Documentation shall also be provided to demonstrate that the method chosen to reduce clearing time is set to operate at a value below the available arcing current.
The arcing current in systems below 1000 Volts is typically around 55% of the bolted fault current.
As far as documentation goes, I would use SKM to provide the calculation.
You would think this would means loads of opportunity for anyone with a power systems analysis package, but it's like anything else with arc flash, it has to be enforced by an AHJ.

I have skm, is there a tutorial or example of how this can be done? I always thought the instantaneous setting was the one that needed to be adjusted. Thank you

 

[mayanees]

If you have the application modelled just right-click on the bus and Go To ARC Flash and TCC. The arcing current will appear as a vertical fault line and then adjust the instantaneous to trip below it.

 

[Cartoon1]

If you have the application modelled just right-click on the bus and Go To ARC Flash and TCC. The arcing current will appear as a vertical fault line and then adjust the instantaneous to trip below it.

Aha, gotcha!! Thank you so much for help!!!!!