GFCI outlet test

https://drive.google.com/file/d/0BwetuXThPOQmZmxwYXNlNGZ6T1E/view?usp=sharing

Sorry for the mild grunting, it’s not in a comfortably accessible spot. The gist is that this outlet, when i use my GFCI tester button, will buzz and THEN trip. If i use the TEST button on the outlet, it trips instantly, no buzzing. Only with the tester’s button does it buzz and then trip.

Is this acceptable behavior or should it be replaced? None of the other 2 GFCI outlets in the condo do this. My feeling is that since it does actually trip, it fine and i shouldn’t worry about it.

If it makes a difference, i live in Maryland, no idea how to find the specific electrical codes for exterior GFCIs.

I couldn’t get your video to play on this computer (probably something on my end) so I don’t know if any of this is answered in the video.

Anyway, a GFCI should trip at 6 mA. However, at 6 mA or currents close to that it may take the GFCI a couple of seconds to trip. Once the current gets up to about 20 to 30 mA or so, the GFCI should trip quickly, maybe 20 to 25 ms or so.

Since I couldn’t see the video I’m not sure what type of tester you are using. With those simple single button testers, you are at the mercy of whatever fault current they designed the thing for. It wouldn’t surprise me if the tester is designed for close to the minimum fault current. That way you know it will trip even at the lowest range of fault currents.

There are more sophisticated testers out there that allow you to vary the fault current so that you can measure exactly what current level is required to trip your GFCI.

Sorry about the video. Let’s try a youtube link instead: https://www.youtube.com/watch?v=oqmSX0HHfpA
The tester is just a cheapo retail kind: http://www.homedepot.com/p/GE-GFCI-Tester-50957/206212330

I checked on the specifications but it doesn’t say at what amperage it uses to test. But it would be the same mA as the other 2 receptacles. Is it safe to assume that since this 1 GFCI outlet does trip (whether with its own button or my GE tester) that it is fine for use and i can tell the inspector (i am selling my condo) to pound sand?

I couldn’t find the technical specs for that particular tester, but if the fault current is down around 6 or 7 mA then the GFCI could be a bit slow to respond, exactly as in that video.

Of course, faster tripping is better, even at low currents, so replacing the outlet with a better GFCI unit certainly wouldn’t be a bad thing. A GFCI outlet isn’t all that expensive either (unless you have to pay an electrician to install it).

Without knowing the specs of that particular tester, my best guess is that your GFCI is working fine.

If you want to be certain about it, the UL spec is that the trip time has to be less than 20 ms for 300mA or greater, and under 300 mA it has to trip within t=(20/i)[sup]1.43[/sup]. That works out to close to six seconds at 6 mA and about two and a half seconds at 10 mA. You’re going to need to know exactly how much trip current your tester uses.

I bought a box of four at one of the large retail hardware stores for a price that beats arguing about it. I have it on a marine aquarium setup, and it works very well. Pouring salt water over a power strip probably produces more than 5 mA, however. :slight_smile: