Code enforcement

[K8MHZ]

surely yes, i guess you can say, a GFCI is just a special GFI, just like a square is a special rectangles, yet all the GF"x"I's are GFI's, and every square is a rectangle

No guessing about it.

GFI ≠ GFCI

Rectangle ≠ Square

 

[FionaZuppa]

Are Class C GFCI's allowed in residences by the standards?

according to UL it protects people. NEC art 100 says Class-A. why NEC does not allow class-C ? its been stated by other well known acronyms that class-A may not be suited for all applications of GFCI's.

 

[FionaZuppa]

No guessing about it.

GFI ≠ GFCI

Rectangle ≠ Square

yeah, you would get an F on this quiz
a GFCI is a type of GFI. they all handle ground faults with same outcome, how they trip = classes.
indeed a rectangle is a square (and vice-versa), a square is a special type of rectangle. was geometry a bad class for you

 

[Carultch]

yeah, you would get an F on this quiz
a GFCI is a type of GFI. they all handle ground faults with same outcome, how they trip = classes.
indeed a rectangle is a square (and vice-versa), a square is a special type of rectangle. was geometry a bad class for you

What would be an example of a GFI that is not a GFCI?

 

[jim dungar]

...the little green screw is related to the fault paths that would allow the GFI give move coverage. agree?

No I do not agree.

The little green screw may or may not be involved.
There are definitely circuits that will cause a zero sequence sensor to operate that only involve normal current conducting paths.

 

[K8MHZ]

yeah, you would get an F on this quiz
a GFCI is a type of GFI. they all handle ground faults with same outcome, how they trip = classes.
indeed a rectangle is a square (and vice-versa), a square is a special type of rectangle. was geometry a bad class for you

This is a square?

 

[K8MHZ]

What would be an example of a GFI that is not a GFCI?

http://www.morningstarcorp.com/products/ground-fault-protection-device/

 

[jim dungar]

No guessing about it.

GFI ≠ GFCI

Rectangle ≠ Square

Time to use the term: Logical Fallacy
Given p=q, then it is necessarily true that q=p.

 

[FionaZuppa]

This is a square?

really?? stop the madness, pls.

rectangle - defined as an equiangular quadrilateral, since equiangular means that all of its angles are equal (360°/4 = 90°). It can also be defined as a parallelogram containing a right angle. A rectangle with four sides of equal length is a square.

so to my own fault, all rectangles are a special type of parallelogram.

What would be an example of a GFI that is not a GFCI?

any GFI that does not have trip specs defined by UL for type "GFCI" (UL943/UL943C) of class A/B/C/D or E

 

[GoldDigger]

Including most high current GF detection breaker or, as the Europeans refer to them Residual Current devices.

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[user 100]

so you know exactly how electricity will flow when a item lands in a pool of water with you in the water? i believe the NEC attempts to not describe such and only looks at the hazard. an item attached to 120/240vac falling into water (tub, other) is a hazard, hence why the use of EGC is important. if it were a 2-prong EGC (GFCI) with 2-prong downstream recepts, then so be it.........

And people who have a 3 prong plug will then do one of 2 things to circumvent this hypothetical 2 wire gfci-

1) Use a cheater plug- (can't begin to tell you how many of these have been found plugged into 2 wire outlets in order to accommodate the fridge in pre '60s kitchens) thereby rendering the 2 wire gfci idea pointless.

2) Remove the ground pin totally so the plug will fit (yes, people are idiots and actually do this:happyyes- not a huge "immediate" deal because the equipment will be fed from your 2 wire gfci but now you also definitely have a potential future shock hazard lurking if this altered equipment is ever moved and plugged into a non gfci receptacle- an example here of the law of unintended consequences.

 

[iwire]

really?? stop the madness, pls.

If you would simply stick to the OPs topic and not bring up squares and rectangles things would go much better.

 

[FionaZuppa]

And people who have a 3 prong plug will then do one of 2 things to circumvent this hypothetical 2 wire gfci-

1) Use a cheater plug- (can't begin to tell you how many of these have been found plugged into 2 wire outlets in order to accommodate the fridge in pre '60s kitchens) thereby rendering the 2 wire gfci idea pointless.

2) Remove the ground pin totally so the plug will fit (yes, people are idiots and actually do this:happyyes- not a huge "immediate" deal because the equipment will be fed from your 2 wire gfci but now you also definitely have a potential future shock hazard lurking if this altered equipment is ever moved and plugged into a non gfci receptacle- an example here of the law of unintended consequences.

exactly two hazards the NEC tries to cover in their code verbiage.

in essence, many many "equipment" or "appliance" that carry elevated shock hazards come with an EGC that is meant to be used. so since a 2-prong GFI receptacle does not exist the EGC should at least be there, and if you have 2-wire downstream then only 2-prong recepts should be there, AND, perhaps you put a "gfi protected" sticker on those downstream items, placing a "no EGC" sticker on the 2-prong downstream items is pointless. if the user decided to do #1 or #2 as you mention then thats on them, but at least the end user doesnt have to read stickers at that point and the GFI is covering as many hazards as it can.

interesting enough, the NEMA docs say that a GFI recept (w/ or w/o downstream items) should have a load on it when using the test button.

now that GFI's are self-testing and acting, do inspectors need to test anything? perhaps they still need to make sure all downstream protected items will trip the GFI ??

 

[Carultch]

Time to use the term: Logical Fallacy
Given p=q, then it is necessarily true that q=p.

Not true. By that logic, given that p is a letter, and q is a letter, that implies that p is q.

When a specific term is stated to be part of a general term, the converse is not necessarily true. Could be true, could be false.

 

[growler]

so you know exactly how electricity will flow when a item lands in a pool of water with you in the water?

I think that electricity will take the path of least resistance. If that path is through me and to ground then I'm in trouble (unless I have GFCI protection). If I expect that current will flow from the hot conductor out and then through my body and then back through the return conductor (neutral) that's going to be a bit hard to figure. If I put a finger of the right hand on the hot and a finger of the left hand on the return that's a problem but that's not easy to do.

Most appliances used in bathrooms and kitchens where GFCI protection is required don't even have a ground to the appliance. They have a 2 wire plug so how would a ground at the receptacle make any difference.

A ground is required for a refrigerator but a frig has a grounded frame with a three wire receptacle.

 

[K8MHZ]

I think that electricity will take the path of least resistance.

Actually, electricity will take all available paths back to its source. The least resistive path will carry the most current, but not all of it if there are other paths to take as well.

 

[Frank DuVal]

I'm old. Back in the 70s, the initials used were GFI, Ground Fault Interrupter.

I sold many a CH120GFI breaker.

Somewhere in the 80s or later the C was added to the initials describing the devices. Why? Someone didn't know a circuit was being interrupted? Was a CH120GFI interrupting a phone call?

Count me as one of the dinosaurs who use the three letters instead of four letters.

GFIs forever.

Now back to discussion of the original post.

 

[GoldDigger]

I'm old. Back in the 70s, the initials used were GFI, Ground Fault Interrupter.

I sold many a CH120GFI breaker.

Somewhere in the 80s or later the C was added to the initials describing the devices. Why? Someone didn't know a circuit was being interrupted? Was a CH120GFI interrupting a phone call?

Count me as one of the dinosaurs who use the three letters instead of four letters.

GFIs forever.

Now back to discussion of the original post.

A picky linguist might point out that the interrupter does not interrupt just the fault; it interrupts the entire circuit.

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[mtfallsmikey]

I'm old. Back in the 70s, the initials used were GFI, Ground Fault Interrupter.

I sold many a CH120GFI breaker.

Somewhere in the 80s or later the C was added to the initials describing the devices. Why? Someone didn't know a circuit was being interrupted? Was a CH120GFI interrupting a phone call?

Count me as one of the dinosaurs who use the three letters instead of four letters.

GFIs forever.

Now back to discussion of the original post.

Frank, I'm old too, and remember when GFI's came out. Remember that they had the same issues with nuisance tripping that exist today with AFCI's? My question is, when did the damp/wet location GFI's enter the market?

Kudos to all involved in this thread, great learning experience!

 

[user 100]

exactly two hazards the NEC tries to cover in their code verbiage.

in essence, many many "equipment" or "appliance" that carry elevated shock hazards come with an EGC that is meant to be used. so since a 2-prong GFI receptacle does not exist the EGC should at least be there, and if you have 2-wire downstream then only 2-prong recepts should be there, AND, perhaps you put a "gfi protected" sticker on those downstream items, placing a "no EGC" sticker on the 2-prong downstream items is pointless. if the user decided to do #1 or #2 as you mention then thats on them, but at least the end user doesnt have to read stickers at that point and the GFI is covering as many hazards as it can.

My point was that real world problems get created if 2w gfci or 2w recs were mandated downstream of gfci protection per your proposal. IMPO, there is not a thing wrong w/ the 406 allowance as written.

The code did an excellent job of meeting in the middle w/ 406.4(D)(2)- recognizing the need to provide shock protection on egc free ckts while trying to ensure that users are aware that true egc protection doesn't exist, and knowing that users may not follow the rules anyway, allowed 3 prong recs downstream of gfci. Its a good solution, so why knock it?

A fridge plugged into a gfci w/no egc may not be legal per 250.114, but it is undoubtedly safer than than no protection at all.