What exactly is the purpose of these things ?

I ran into this particular problem on a house remodel about a year ago, when 2 inspectors I had to deal with insisted the recep wasn't functioning correctly because their tester wouldn't trip it.

I told them both that GFI testers, including my fancy adjustable Hubbell will not not work on ungrounded GFIs, I also tried telling them that the only way to properly test a GFI is with the test button on the device since most homeowners probably don't have a tester, but they both told me to fix it by adding a ground or , as one guy said, "just put a 2 wire outlet there"

So I wonder why we need these things since the tester needs a ground to trip the GFI, while accompanying install paperwork only calls for attaching a ground if one is available

It simply sounds like an inspector without a clue. I would talk to the CBO (respectfully) and confirm the fact that the AHJ is not amending 406.3(D) and work out from there.
Hopefully there will be a quiet "inspector tune up" and things will be better for everyone.

No plans to clear the problem up through complaints, The E.I. is an old friend and working buddy and I have no desire to rock the boat in his pond. He cleared the permit and won't be back

The other guy ( the one with the 2 wire idea) is a Housing Authority inspector working off a checklist….. no thinking involved
The house is a rental that ended up with a Sec. 8 tenant, which is why he showed up.

The GFI is in the kitchen next to the sink of course, so I changed it to a 2w, which can't be tested, then I re-installed the GFI after he left. He'll be back next Feb. for his annual inspection, he'll fail the GFI and I'll play his game again.

why the testers are even used since they need a ground to function

You are not "rocking the boat" when you resolve problems like this you are plugging a hole in the boat.
If he really wants to go back to the 1975 code, you can grab a cold water pipe for your ground. Let him make a choice.

a good way I found to test the GFI without a ground is use an induction tester like the ol' wiggy .. hot to hot then the negative lead to any nearby grounded reference like the sink faucet, it always tripped the GFI ..

neat story, I was under a house once and came up against a box that had the same color for their two wire circuit . before slithering out from under the house to get a cord I thought, hmm .. I'm laying on Ground .. so I grabbed my large screw driver jammed it into the dirt, got my tester used the screw driver as my negative reference and was able to correctly determine the correct hot wire.. that was cool. ..")

Not going to work when the plumbing is non-metallic or the flex connectors supplying the faucet & drain fittings are non-metallic

By testing a GFI, do you mean proving that it will trip, OR proving that it will trip at a current that won't be lethal to you??? We did this thread a few years ago. I need a Wiggy volunteer since I can't find a good spec. sheet for one. Test an outlet with your Wiggy in series with a Fluke on AC mA, and let me know how much current you're drawing. If its substantially greater than the value at which your GFCI should trip, (I'll bet it is.), then you're not performing a useful test. I tested an outlet at work once. 120V/10mA=12kohms. Ckt would dissipate 1.2W. I think I used a 12K, 2W resistor in series with a 50K pot, set to max., in series with my Fluke on AC mA. Going Hot to Ground, I decreased resistance slowly until the outlet tripped. I seem to recall that it was at about 7mA, a little more than I expected, but still safe. I was wondering what the spread would have been on several devices of the same part number.
Joe

I was trying to prove that the GFI was working as designed and all I wanted was for those 2 different inspectors to understand that their method of testing an ungrounded GFI ...during their respective finals... with a pocket tester was not the way to determine if the unit was functioning properly !

using wiggys, Flukes, and the kitchen sink for tests, while fun to do, are not things I want to do during final inspection(s)

As far as determining trip currents, Hubbells GFT2G adjustable tester ( which is the one I have used for decades ) incrementally increases the leakage up to 7ma, but it also requires a ground to work and would have failed to trip that particular GFI as well

You simply push the test button and insure the down stream receptacles are deenergized.

Ditto. That's the UL standard

Sounds like US regulations are a bit less restrictive than most European ones that I'm aware of. Here you're typically required to measure trip time at nominal trip current and preferably also trip current. The only way to do this in the setup discussed here would be an auxiliary earth, e.g. from an extension lead plugged into a nearby earthed socket or even a long wire connected to the main earth.

I also have a Hubbell GFT-2G. It sits in my desk drawer.
Inspectors use the 'bug eye' cube tester, polarity & GFI trip test.

If the Hubbell had polarity indication, it would be in the cars.

IMHO, following the UL standard detailed above, still requires polarity confirmation.

You could also test the GFI by going to a nearby Neutral, but you could end up with 2 tripped GFIs instead of 1. That could be the case if the N was from a receptacle downstream of another GFI and lacking one of those little stickers.
Joe

My question is this. If the house is an old 2 wire system with no ground, and if you install GFCI's, will the personnel be protected against electrocution? Example: if a microwave is plugged into a GFI that has no ground and the hot conductor goes to ground on the microwave frame, and the person is touching the cold water faucet in the sink and the frame of the microwave at the same time, will the GFCI trip? in time? I don't think so. So what's the theory behind replacing 2 wire plugs with gfi's? I have an old house that is wired with 2-wire system inside but the service is fairly new and grounded. How can I make the circuits inside the house safe? would GFI breakers work?

Billy3169

A 'basic' explanation of the internal operation of a GFI device is:

The current on the black (hot) and white (neutral) are monitored and compared. Any difference between the current on hot & neutral that exceeds the threshold of the device will 'open' the circuit.

Based on the above, the EGC is NOT required for designed function of a GFI.

The discussion is this thread is reflective of the use of various GFI testers, which require a functional EGC to operate & trip the GFI.

Hope this clears this up.

OK, thanks John. I'm kinda new to this website, guess I will have to open a new thread to find out if this will work on a gfci 2 pole main breaker.

Billy6139:
OK WELCOME to ECN forums!!

THe theory on GFIs is the same, monitoring for any unbalance.

Go ahead, start a thread, and let's see what happens.

Billy,
If you find a path to ground, then there will be less current returning and the GFI should trip. If you can't find a path, no completed ckt, no worries. If you find a path to ground but the source is somehow isolated, no ckt, no trip, and its time to troubleshoot the missing ground reference.
Welcome!
Joe

Thanks Joe, can't figure out how to start a new thread. I have a 2 unit apt building. All inside wiring is ungrounded 2 wire system. 2 meters and mains outside, fairly new and grounded. 1 unit has 2-50A 2p breakers feeding a sub panel, all screw-in fuses and a range. If I replace the 50A 2p with a 50a 2p GFI Breaker feeding the sub panel, will it protect the circuits inside or will I have to install gfi outlets or outlet with feed thru capabilities if I can figure out the wiring inside. Any help would be much appreciated.

Billy,
I think that we should hold to a philosophy of trying to protect people (and animals) from shock without making whole buildings go dark. I would rather get a zap from 120, than fall down the stairs when the light goes out. Protect your loads where necessary. Ask yourself if there are cases where removing power creates risk.
Joe

Good point joe, I hadn't thought of that. I will take that advice. Thanks again Billy

Billy:
To start a new thread:
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Gee,
You guys have it easy over there!

On this side of the black stump, every electrician that certifies work that entails RCD's (GFI's) is required to test every RCD protected circuit and record the trip time and current on your Certificate of Compliance.
The proper tester for this costs an arm and a leg and maybe some fingers too.

As a quick test though when fault-finding, I use a solenoid type voltage indicator that draws about 240mA when you press the solenoid button on it.

Same here. I paid €1000 for my tester and now I'm probably the only DIYer in the entire country that owns one (at least a new, recently calibrated one). And that was a budget model (though the top-notch one in this class), Flukes and Chauvin-Arnoux go up to €4k. There are €500 models too (or at least were when I bought mine last year) but they usually lack a few essential functions like earth resistance measuring.

I've got a 2-pole voltage tester that draws slightly over 30 mA in load mode (there's also a high-impedance mode that's handy for deciding whether an earth wire is connected at all without tripping the RCD). While not an acceptable tester, it's a farily good indicator that shows if the RCD works more or less like it should, provided it's a 30 mA. 100 mA and up don't trip at all and 10 mA are tested at well beyond their nominal fault current, so you can't really say whether they work properly.