Can you trust the test & reset buttons on a GFCI?

[myredracer]

Below is a link to an interesting thread on the Mike Holt electrical forum about whether or not GFCI's work properly as intended and if they're in compliance with UL. This may be of interest to RV-ers as we all have them and they do sometimes cause problems. Perhaps getting a GFCI tester would be a good thing to have.

To quote the thread starter "LED indicators, SmartLock technology, internal self testing and the test/reset buttons do not accurately verify that a GFCI is functioning correctly. They do not tell you the speed at which a GFCI will trip, nor do they demonstrate that power has successfully been interrupted once the receptacle has tripped. Plugging in a load does not guarantee it either."

Warning - it is 19 pages and nearly 200 posts long.

Mike Holt forum GFCI discussion

The thread also points out that there is a revision to UL 943 effective June of last year requiring a self-test function and line-load reversal miswire function. If you are buying a new GFCI receptacle, you might want to check that it complies with the latest UL standard and not just that it says "UL listed". Begs the question - how many RVs purchased after June/2015 have GFCIs that comply with the latest revision? (Installers are permitted to install old stock tho.)

I wonder how many 20 amp GFCIs in pedestals could be faulty?

[Harvey51]

GFCI is supposed to trip at or below 5 ma, so a good test is to stick a 20 k ohm resistor into the outlet from hot to safety ground and see if it trips.

I got my first wee tingle from a GFI standing in water in rubber boots and holding an old sump pump. Just a little tingle before the GFI tripped. I was glad I had plugged it into a GFI outlet. Good device. Too bad they each use $5 of electricity per year now. And arc fault interrupters twice as much.

[wa8yxm]

I see a problem with that automatic self test..
(What is it you ask)

Per the article as I read it it means that from time to time the GFCI will, in a manner of speaking, press it's own TEST button, and trip. (one way it can work).

Imagine if that GFCI is feeding a CPAP and you, as a result, do not wake up in the morning.

Or if it's feeding a fridge and by the time you reset it all the food is spoiled.

Or.. Well several other disasters.

Do I trust the buttons? I trust them for the purpose they are designed.. but I play safe when working with Electricity or electric tools. I grew up BEFORE we had GFCI's to protect us.

[westend]

My Dad gave me my first lesson about electricity. While trying to make functional a string of series powered Christmas lights, he suggested that I put my finger in an open socket, just like I was trying to accomplish. It was a valuable lesson.

BTW, I don't suggest anyone do this as a parenting technique. There are other ways to teach the effects of electricity on the human body.

[D_E_Bishop]

I haven't had but two or three failures in my career and I feel that they are pretty cool devices. Having one on a circuit in my carpeted house is overkill, having them outside and in wet locations, prudent.

We had some 25 amp made especially for our signal systems and they had surge protection built into the assembly. Overkill maybe but, with 4500 computers in vented aluminum cabinets installed outdoors and protecting folks from exposure to shocks and the computers from all sorts of chip killing situations, cheap insurance.

[MEXICOWANDERER]

Ordinary Mechanic'c NITRILE GLOVES are excellent protection when working around live circuits. They are inexpensive. Use TALC on the hands to make on and off effortless.

[Chuck_thehammer]

last hit from electrify, 1988, working on LIVE power amplifier.(needed to). 5,000 volts but little amps... I did not touch, it jumped. then I did.

I learned where and where NOT to put my fingers.

GFCI are to sensitive..my opinion.

[MEXICOWANDERER]

Does sticking left index finger into "L" Megawatt terminal, count?

[drsteve]

pianotuna wrote:
How many folks have actually gotten a shock from a non gfci connection?

(raises hand) More times than I can count.

[DrewE]

drsteve wrote:

DrewE wrote:
In my opinion, it would not be a bad thing to have GFCIs on every electric circuit in a house or RV, at least on every circuit that has an outlet or light with a removable bulb. They can and do save lives.

No argument that they are a good safety device, especially in wet areas, but the NEC does not require GFCI protection on overhead lighting circuits. You wouldn't want to be left in the dark by a random trip of the sort GFCIs are famous for.

RV lighting is 12VDC so GFCIs don't apply.

Indeed the code does not require GFCIs for many circuits, and I didn't mean to suggest thag. AFCIs, a somewhat different beast, are now required and from what I have read more prone to falsely tripping. In my (limited) experience, GFCIs are not overly prone to false trips, but ground faults can be devilishly tricky to track down.

(AFCIs are arc fault circuit interruptors and attempt to stop sparking loose connections and similar problems. Telling sparking motor brushes from sparking loose wjre nuts doesn't always work.)

[drsteve]

DrewE wrote:
In my opinion, it would not be a bad thing to have GFCIs on every electric circuit in a house or RV, at least on every circuit that has an outlet or light with a removable bulb. They can and do save lives.

No argument that they are a good safety device, especially in wet areas, but the NEC does not require GFCI protection on overhead lighting circuits. You wouldn't want to be left in the dark by a random trip of the sort GFCIs are famous for.

RV lighting is 12VDC so GFCIs don't apply.

[Kayteg1]

I've been shocked by European 220V few times.
It is pretty itchy, especially in humid weather.
In CA I had couple of situations, when standing on plastic bucket I was connecting outside light. With 3-way switches you are never sure if the light is on or off, but I always tap the wires before touching them.
So tap gave me no shock, allowing me to twist the first wires with my bare fingers and putting wire nut on it.
Than I put other wires together and the light come ON !!!
Standing on plastic bucket on dry ground I was like bird on a wire.
Anyway. New building codes made my putting AFCI in my new house.
Over the time I had them popping up. One turned out to act to my laptop charger.
The other would break with central vacuum.
So in the end I replaced $50 AFCI breakers with $4 traditional ones.

[coolmom42]

The biggest single hazard (IMHO) that GFI breakers protect against is the connection between small appliance and water..... so if your toaster falls in the sink you don't get shocked. OR if your child or grandchild decides to see if the hairdryer will blow bubbles. Thus the code requirements that receptacles above a countertop with a sink be GFI protected.

[Tom_M1]

pianotuna wrote:
How many folks have actually gotten a shock from a non gfci connection?

I've been bit a few times. The last time was when I got across a GFCI protected circuit. Instead of good jolt it was a sting.

[ktmrfs]

while I practice care around electric systems, I'll agree with Drew E and disagree with Old Biscuit. Currently most every branch circuit in our house that supplies outlets lights etc. has GFI protection. The exceptions are the power to the fridge and freezer. That is because of the reasoanble possiblity of a false trip with leakage current in the motors/compressors. And my house 30A RV circuit also has a GFI breaker.


But then it's not just me in the house, it's DW, kids and Grandkids. And on more than one occasion I have done some stupid things around electric circuits, and other stuff. You never know when protection may help.