Josue

So a GFCI receptacle will trip if there is a fault of 5mA and a GFP will trip for example with 5A?

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user4818

Yeah. GFP protection is usually rated around 30 mA, which is above lethal levels. GFP for large services may be rated even higher, I'm not sure though.

Josue

Thanks!

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user4818

You're welcome.

BBQ

GFCIs (Ground Fault Circuit Interrupters) are intended to protect people

GFP (Ground Fault Protection) is intended to protect equipment, and the trip rating can be miliamps to 100s of amps depending on what is being protected.

Josue

Thanks.

So which is more sensitive, the GFP right?

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user4818

Technically, the GFCI is far more sensitive, because it trips at a much lower.

Josue

ok

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BBQ

A GFCI is required to open when the current exceeds about 6 mA, on the other hand many GFPs for services are set at 400 to 800 amps.

This is an oversimplification as time has something to do with it as well.

don_resqcapt19

Dennis,
My point is is that the GFP part of the previous AFCIs did most of the work. In talking with a AFCI decelopement engineer from Eaton, I was told that 90 to 95% of the trips are GFP trips and not arc signature recognition trips.

The AFCI arc signature recognition does not look at "series arcs" with a current of less than 5 amps. Glowing connections (a form of series arc) can produce enough heat to start a fire at well less than 5 amps. With a wiring system that includes an EGC, there will often be a ground fault before a fire starts and the GFP part of the AFCI provides that protection.

It is an even bigger part of the protection of the original branch circuit/feeder type of AFCIs as they did not even look at series arcing faults and did not look at parallel arcing fauts of less than 75 amps.

Dennis Alwon

I do understand and I do not know why it is allowed if it were such a big issue. If that were a true concern then GFP should be required also but it is not so I am not sure that the GFP faults that occur are necessarily a fire hazard.

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don_resqcapt19

I am not sure of that and I really don't believe too much of what the manufacturers and UL tell us about AFCIs.

These are the people that said, in the original AFCI proposals, that they had a device ready to market that would do what they now tell us the combination type AFCIs will do. Those original proposals were some 13 years before the combination type AFCI hit the market.

frenchelectrican

Don.,

I know that question will pop up on moi one way or other anyway the standard branch RCD will genrally can catch the arc series arc due the unblanced load and rapid cycling just enough to trip the RCD but for the main RCD breaker the chance to see the Main RCD breaker to trip from series arc is very small unless the branch RCD is malfunctioned.

Again., The RCD is primarly used for GFP due they are on higher ma setting and we do have 3 diffrent setting we used depending on location it being used. The main RCD typically have 100 ma while branch RCD are at 30 ma and for bathroom or pool useage they are at 6 or 10 ma setting { it depending on which manufacter we get it from }

There were few case the RCD did tripped from series arc but parallel arc ., AFAIK they don't trip unless it combined with ground fault situation arise.

Merci,
Marc

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Shockdoc

i always liked GE loadcenters and breakers

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ce2two

I have dumb question WHY on commercial switch gear did they start at 1000 amps for G.F.P .Clue me in?

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Big John

I've seen GFP set a good bit lower than that, but a setting that high is probably for selective coordination: If there's a ground-fault in a branch circuit, you want the branch breaker to have a chance to clear it before it dumps the main. A feeder fault off of the gear is usually gonna be a heck of a lot more than 1000A so it's safe to have it set that high and still be effective.

-John

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sbrn33

I know for a fact that Seimens arc-fault can only be tested with their buttons. I received an email from their tech dept. that stated this fact. I will look for it tommorow if this thread is still active.

zoopenny

So I was on a service call for an AFCI that kept tripping. Traded it out and it still tripped. Divided circuit in half, still tripped. Finally located a J-box in attic with loose wirenut from previous electrician... getting toasty. Hmmm it wasn't the crummy AFCI, it was DOING exactly what it was designed to do! The homeowner was CONVINCED it was the breaker. Glad I reserved any comments until I had the answer! With that example it seems like it wouldn't be that hard to make an AFCI tester. Put in a small load device and a simulated loose wirenut-- wouldn't that work?

HARRY304E

Good work that is the # problem poor workmanship bad splices lose device screws.......

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