ECN Forum Forums General Topics of the Trade General Discussion Area GFCI & grounding

Mark,
How many mA does your wiggy draw? The test resistor is sized to pull 8 mA at 120 volts. Also in the rare case that the metal that you put the other probe of the wiggy on is not grouded, you will energize it creating a hazard for anyone touching that metal and a grounded surface.
Don

.......The problem I'm having is this......
I put in GFI's in systems that for one reason or another have no grounding at the 1900 box. Sometimes it's a real pain-in-the-ass to establish a ground to this location. The home inspector or the village inspector comes in....plugs in his red tester....and says: "no ground! can't pass it."
So I have to 'find' the reason for the "no ground" condition or cheat a ground wire from a cold water pipe to the box or in some cases tear the walls open because the EMT has seperated in the wall or the compression fitting has come undone or whatever the reason is.
Another electrician told me there was a way to wire the GFI with no ground present so that it "passes" the inspector. If it works and truly is safe I want to know about it so I don't have to hassle with inspectors or tear walls open or cheat a ground.

Rowd, the only way is not safe and I just ran into one of the worst case senarios of this. An electrician jumpered the ground screw to the line neutral screw. The worst part came when he cross wired it, hot to neutral
neutral to hot. I discovered this when I plugged a drill into the GFI and went to drill a hole in a sub panel. Sparks flew and fuse blew in hidden fuse panel. Took a little time to track down where the fuse was and then pulled the GFI for the discovery. Luckily nobody hurt, just my got my heart pumping a little faster.

[This message has been edited by stamcon (edited 09-27-2002).]

Paul
I understand that, my only point was that a test outside of the 'Internal Electronics', would be a sure way to test it, aside from pushing the button.

Don
dont know how many amps/miliamps it draws to energise it, the point is the GFCI is suppose to trip when the comparator inside the gfci is switched, and that happens at about 6ma, as a matter of fact any differential amp will switch at that current, my whole idea was to use something other than the internal test button, and yes the grounded surface could become energised, but I am not making a permanent connection there either only for the purpose of a test.
The internal test is sort of a sterle test unto itself, the internal resistor is calibrated to set the device of at the trip point, I was suggesting a way to test it without an egc being present, where in old construction there is no equipment ground but oft times there is plenty of grounded surfaces available.

mark

Mark,
What don't you like about the internal test button?
Don

rowd....

what does this individual not understand about 406.3(D)(3)(b) ?

all you need do is mark it
'no equipment ground'

Don:
No problem with the internal test button on a gfci it works fine but to me it is supposed to work fine.
But when there is a fault caused by careless use, or just a fault(let me qualify this, a ground fault) pure and simple, it does not see that internal resistor but will fault to ground as I mentioned, to me it is a back-up to ensure that the device will operate as it is suppose to.
And the original question was how to test them when there is no EGC present, aside from the test-button, and especially in front of the customer it is also dramatic and they too are assured that what they are paying for will work.
That was all I was saying, just another way to demonstrate that this is a product that will function when it is supppose to.

Mark

If you really want to demonstrate it tripping without pushing the test button, then you'll just need to find some other way to unbalance the current. How about getting a ground (or a neutral) from an extension cord which is plugged into some diatant receptacle? (Obviously the latter would have to be one which isn't fed from the GFI under test if you're using the neutral.)

Paul:
If I go to a grounded surface why would I have to run an extension cord? For example, a radiator ? A Basin ? Most of these older homes have copper or galvanised pipe for waterlines.
As I said to Don, the original question was to test these devices without pushing the test button, all I am saying is,"Hey here is another way to do it".
The internals of a gfci is basically an op-amp, and a 'Wiggy' will create enough imbalance to trip it.
I have done this numerous times and it works

Mark

I think what really needs to be done here is to teach the inspectors that the code does permit the installation of GFCIs without an equipment grounding conductor, and that the test button fully tests the functionality of the GFCI just as well as any other type of tester.
Don