GFP ????

[jimbo123]

There was a incident awhile back where a 20amp circuit faulted to light fixture or conduit . circuit was at 277v feed out of a 100a panel which came from a mcc bucket , mcc was fed with 500a cb w/gf protection. 500cb came from the switchgear .
When the fault happened it carried back to the switchgear 500a cb and tripped [ it bypassed 3 molded case cb till the 500a @ SG ]. This caused the mcc to trip and building to shut down.
Besides having a cordiation study completed does anyone believe the lighting circuits or lighting panel should have GFP in the mean time ?
Or something else ? THANKS.

 

[iwire]

I think the only required action is the study and the correct settings dialed into the breakers.

Without knowing the settings of the existing breakers adding GFP to the branch circuits might help or it might not.

The main could still trip first or simultaneously as the branch circuit GFP.

The study will likely conclude to add some delay time to the GFP main.