GFCI/AFCI vs EGC

[INGMRS]

Hello,

I have a question, ¿what is the purpose of the EGC in a branch circuit when you have it protected with a GFCI/AFCI OCPD?, ¿Is it just a Lightning issue or ESD?

Regards.

 

[hbiss]

It makes no difference if a circuit is supplied by a GFCI or AFCI. The requirement and purpose is the same.

-Hal

 

[ptonsparky]

It is a lot easier on your body when ground fault current flows through a conductor vs you. It does hurt. You won't want to repeat the experience.

 

[LarryFine]

First keep in mind that the EGC preceded the GFCI by decades.

The purpose of the EGC is so accidental contact between a hot wire and the case of an appliance will mimic a hot-to-neutral fault and trip the breaker before a person receives a shock.

A GFCI functions by detecting a difference in the currents in the wires of a circuit, presuming that the difference is current passing through a person to earth outside of the circuit.

 

[Dennis Alwon]

The point is that although the gfci may keep you from getting killed you will still receive a nasty shock. Hopefully the equipment grounding conductor will trip the breaker long before you come in contact with some energized parts

 

[winnie]

Given residual current detection, IMHO there should be some reduction in EGC requirements. But without significant data on things like GFCI reliability and longevity, I wouldn't know how to even start a proposal.

For example if all circuit breakers included _mechanical_ residual current detection (not class A life safety GFCI, but rather long term reliable but less sensitive detection) then I'd be entirely comfortable with reducing the size of EGCs.

-Jon

 

[petersonra]

I'd be entirely comfortable with reducing the size of EGCs.

The size of EGCs required by the code is based on making sure the OCPD ahead of a ground fault trips quickly. It is pretty conservative so people don't have to get a calculator out to figure what size it needs to be. I don't see that there is much to be gained economically by reducing the required size of the EGC anyway.

 

[suemarkp]

The egc is still a 24/7 path that a leak could take and trip the gfci. That better than having to wait for someone to touch it to allow leakage current to flow nd trip the gfci.