gfci settings

[chechy]

I have a 1600 amp 480v service with shunt trip ground fault protection
Recently a shorted ref compressor took out the whole building.
The compressor was fed by a 3phase 70 a 480v bkr.
neither the 70a bkr or the 150a bkr feeding the panel tripped when the comp. shorted

The question is: does anyone no how to pick the right settings on the shunt trip gfi bkr? on the bkr it has time delay: 1-1 sec (originally set to.1)
current pick up 100a-1200a (originally set to 100)

 

[charlie b]

That is not enough information. First of all, it is by no means certain that the ground fault element is what caused the main breaker to trip. If there has been no effort to create a coordinated system, then it is possible that a 20 amp receptacle circuit can sustain a fault that could take out the building's main breaker.

In order to establish proper coordination among the three breakers you described, what is needed is the make and model number of all three. But even if you got those three coordinated, there are still many other combinations of breakers within the main panel, the distribution panels, and the branch panels, any one of which can lead to a loss of more than the loads that are closest to a fault point.

Selective coordination is now required in certain emergency and legally required standby circuits. It is not required in normal distribution systems. If you want to obtain a fully coordinated system, then you will need to engage someone who knows how to perform that type of analysis.

 

[zog]

I have a 1600 amp 480v service with shunt trip ground fault protection
Recently a shorted ref compressor took out the whole building.
The compressor was fed by a 3phase 70 a 480v bkr.
neither the 70a bkr or the 150a bkr feeding the panel tripped when the comp. shorted

The question is: does anyone no how to pick the right settings on the shunt trip gfi bkr? on the bkr it has time delay: 1-1 sec (originally set to.1)
current pick up 100a-1200a (originally set to 100)

This is not a GFCI, this is GFP, apples and oranges. GFCI's are for protecting people, your GFP is for equipment protection.

The reason your main tripped is likely because the other breakers do not have GF protection, someone saw that as a cost savings during the design/build process.

The GF settings should be determined by a coordination study, or set to the minimum if no study has been done.

 

[chechy]

gfci setting

gfci setting

The control on the gf was tripped along with the 1600a main. After resetting both values to half , i tried the 70 a bkr. it tripped along with the 150a that fed that panel. the main didnt trip. Im not comfortable with the half way selection. All equipment is 2 years old, same manufacturer, and was installed as a system.

That is not enough information. First of all, it is by no means certain that the ground fault element is what caused the main breaker to trip. If there has been no effort to create a coordinated system, then it is possible that a 20 amp receptacle circuit can sustain a fault that could take out the building's main breaker.

In order to establish proper coordination among the three breakers you described, what is needed is the make and model number of all three. But even if you got those three coordinated, there are still many other combinations of breakers within the main panel, the distribution panels, and the branch panels, any one of which can lead to a loss of more than the loads that are closest to a fault point.

Selective coordination is now required in certain emergency and legally required standby circuits. It is not required in normal distribution systems. If you want to obtain a fully coordinated system, then you will need to engage someone who knows how to perform that type of analysis.