Ground Electrode Conductor/Grounding Electrode

[Eduardo Maun]

I have read that GEC/GE are both path to earth for lightning, but it's not path to source because earth is not a low impedance path to source. What is this?Does the author says the panel is not protected with GEC/GE? Isn't it once a fault happen there will be a current flowing in the body of an equipment/panel? So how will they protect this?

 

[don_resqcapt19]

Ed,

Isn't it once a fault happen there will be a current flowing in the body of an equipment/panel? So how will they protect this?

The only way to protect from this is to stop the flow of current by having a low impedance fault clearing path that will permit enough current to flow so that the OCPD will open quickly. Until this happens the non current carrying metallic parts of the equipment where the fault is will have a voltage to earth equal to the voltage drop on the fault clearing path. All other non current carrying parts of the electrical system will have a voltage on them equal to the voltage drop on the fault clearing path that is on the line side of the main bonding jumper.
Don

 

[radiopet]

100% agreed with Don.........the Earth will never clear a fault in relation to 600V or less systems. In the systems we normally deal with the low impedance path is critical for an OCPD to function...not the earth.


Again they protect it by allowing the low impedance fault current path back to the source ( power supply ) which allows the ampacity to rise above the allowed levels of the OCPD in place protecting that circuit...which then allows it to trip....before it becomes a touch potential danger...the lack of an effective low fault current path would cause the equipment to remain energized and a serious hazard.

 

[BnE]

Are you trying to ask is the ground system in a building is a path to ground in relation to a lighting strike, then I believe it is because otherwise lighting would not strike there. and as a whole I think the earth is a low impedience conductor, again, as a whole.

 

[George Stolz]

I think the earth is a low impedance conductor, again, as a whole.

That may be, but our ability to connect to it generally stinks.

Copper is a great conductor, but I wouldn't want to be touching a circuit in a ground fault if the Equipment Grounding Conductors were simply stripped back aways with a zip tie holding them together for contact.