GFI & GFCI

[Alwayslearningelec]

Is below accurate? I googled and found the response.


A GFCI is a ground-fault occurs when there is a break in the low-resistance grounding path from a tool or electrical system. The electrical current may then take an alternative path to the ground through the user, resulting in serious injuries or death. The ground-fault circuit interrupter, or GFCI, is a fast-acting circuit breaker designed to shut off electric power in the event of a ground-fault within as little as 1/40 of a second. It works by comparing the amount of current going to and returning from equipment along the circuit conductors. When the amount going differs from the amount returning by approximately 5 milliamperes, the GFCI interrupts the current.

And a GFI is a ground fault interrupters are designed to protect from electrical shock by interrupting a household circuit when there is a difference in the currents in the "hot" and neutral wires. Such a difference indicates that an abnormal diversion of current from the "hot" wire is occuring. Such a current might be flowing in the ground wire, such as a leakage current from a motor or from capacitors. More importantly, that current diversion may be occuring because a person has come into contact with the "hot" wire and is being shocked. When a circuit is functioning normally, all the return current from an appliance flows through the neutral wire, so the presence of a difference between "hot" and neutral currents represents a malfunction which in some circumstances could produce a dangerous or even lethal shock hazard.

 

[yankj]

I would say it's not totally accurate. The second paragraph says something about returning ground fault on the neutral; no so. Fault could be on the neutral. Anytime current leaving GFCI does not match current returning within 5 mA, GFCI is supposed to open. GFI and GFCI are same thing.

 

[jim dungar]

GFI and GFCI are same thing.

Actually GFI is the generic name for this type of protection (current going out and coming back are not equal).
GFCI is a special name for 'people' protection, it has very specific operating parameters (i.e. 5mA trip).

 

[Alwayslearningelec]

I would say it's not totally accurate. The second paragraph says something about returning ground fault on the neutral; no so. Fault could be on the neutral. Anytime current leaving GFCI does not match current returning within 5 mA, GFCI is supposed to open. GFI and GFCI are same thing.

Thanks.

 

[Dennis Alwon]

Perhaps you are thinking of the difference between GFP and GFCI. IMO, GFCI is the same as GFI

 

[infinity]

To me GFI and GFCI are the same thing, GFCI/GFI and GFPE are not. The latter has a threshold of 30ma and is used to protect equipment not people.

 

[zog]

To me GFI and GFCI are the same thing, GFCI/GFI and GFPE are not. The latter has a threshold of 30ma and is used to protect equipment not people.

GFPE has a lot higher threshholds than 30mA, it is usually around 30% of the breaker rating, if said breaker has a GF function. GF are sensed via a nuetral CT for 4 wire systems or via current imbalance on wire wire systems.

I think a GFI has the 30mA threshhold and a GFCI has 5mA, but they both perform functions in the same manner. Not sure on this though, GFCI and GFI may be the exact same thing.

 

[goldstar]

I think it's a matter of semantics. Somewhere along the line one of the CMP's decided we all would better know what the meaning of ground fault would be if they changed the language from GFI to GFCI. Kind of like changing MCM to KCmils. Fortunately I can still go into the supply house and order cuts of 350 MCM and the counter guys still know what I'm talking about. Same thing goes for GFI receptacles.

 

[jim dungar]

GFCI is the specific device for 'people protection', GFI is not. Try searching the UL White book for 'GFI'.

GFI is an undefined generic term which, as you can see from this discussion, is not universally used.

Many people, and some manufacturers, use GFPE for 30mA devices, but UL calls these "Eq. GFP".

I started in the industry using a generic GF or GFP and then calling specific devices as GFI for ground fault interrupting (tripping) and GFA for ground fault alarm (annunciating).

 

[PetrosA]

I thought GFI describes a type of device (GFI receptacle, GFI breaker) and stands for Ground Fault Interrupting, while GFCI is the device itself and stands for Ground Fault Circuit Interrupter. Class A would be 5mA while Class B would be 30mA.

 

[CopperTone]

Is below accurate? I googled and found the response.


A GFCI is a ground-fault occurs when there is a break in the low-resistance grounding path from a tool or electrical system. The electrical current may then take an alternative path to the ground through the user, resulting in serious injuries or death. The ground-fault circuit interrupter, or GFCI, is a fast-acting circuit breaker designed to shut off electric power in the event of a ground-fault within as little as 1/40 of a second. It works by comparing the amount of current going to and returning from equipment along the circuit conductors. When the amount going differs from the amount returning by approximately 5 milliamperes, the GFCI interrupts the current.

And a GFI is a ground fault interrupters are designed to protect from electrical shock by interrupting a household circuit when there is a difference in the currents in the "hot" and neutral wires. Such a difference indicates that an abnormal diversion of current from the "hot" wire is occuring. Such a current might be flowing in the ground wire, such as a leakage current from a motor or from capacitors. More importantly, that current diversion may be occuring because a person has come into contact with the "hot" wire and is being shocked. When a circuit is functioning normally, all the return current from an appliance flows through the neutral wire, so the presence of a difference between "hot" and neutral currents represents a malfunction which in some circumstances could produce a dangerous or even lethal shock hazard.

is there a point here?