Are "2 prong" outlets less safe?

Factual Questions
21

Okay, what I was talking about, and what I thought Dave was talking about, was whether you needed to have every wall outlet in your house be a 3-prong outlet, on the off-chance that someday you might want to plug some 3-prong things into it. My response was, “No, you don’t have to have all your wall outlets modified to be 3-prong outlets on the off-chance that someday you might need to plug a 3-prong thing into them. It’s okay to plug 3-prong things in to a 2-prong outlet with a 3-to-2-prong adapter.”

And I stand by that–why would they make them if they weren’t safe?

IMO, if you use a 3-to-2-prong adapter, you are circumventing a very minor safety feature.

I have all my computer peripherals and aquarium equipment plugged into power strips which with adapters are plugged into 2-prong extension cords which are plugged into 2-prong outlets. And yes, the aquarium stuff, both in the living room and in the basement, has GFCIs installed on the outlets.

BTW, I’m married to someone who routinely clips off the third prong anyway, so as to make it fit.

[entire population of thread sighs, “oh god”]

Sorry guys. :smiley:

22

Haven’t hired an electrician for a while, huh, Chronos? :wink:

23

oh god! :slight_smile:

They are safe if you attached the ground wire on the adapter to the screw holding on the cover plate, and if that screw is grounded through the receptacle back to an earth ground.

It’s a completely useless feature until the once-in-a lifetime failure happens, then it can be life critical. A lot of equipment is double-insulated nowadays, so it’s getting less and less likely that you’d actually get shocked, but it only takes one time!

At the very least, you should use polarized plugs, and make sure hot and neutral aren’t swapped (although you probably would have found out the hard way by now if they were). A tester is just $6.79.

Remind me to wear my gloves when I visit :slight_smile:

24

I’ve lived and worked in places where nothing was grounded, the plugs and outlets weren’t polarized, and the voltage was 220VAC. I observed a few things. In one house, if I lay down on my bed after showering with my wet hair against the wall, I got quite a tingle. In one office, I’d get a really annoying tingle every time I touched the computer case. In another house my wife touched a wall-mounted air conditioner (or possibly just the wall near it) and got a shock that put a lighting bolt-shaped crease in her arm that lasted for years. At another house (not mine) a child who went to school with my kids was killed when he touched a (obviously ungrounded) lighting fixture near a swimming pool.

Now I live in a 110VAC country in a house with some ungrounded outlets and I either ground them (a long term project), protect them with GFCIs, or am careful about what I plug into them.

25

More personal anecdotes:

I’ve been badly shocked before. My dad is an entomologist, and had set up a light trap (bug catcher) in the back yard back when I was in first grade. This light trap was a metal funnel on a metal stand, with metal vanes above the funnel and a flourescent black light tube down the center of the vanes. It was old, and a bare hot wire made contact to the chassis. I was wandering around in the backyard barefoot, the soil was moist. I brushed one of the legs of the light trap with my right hand. It clamped on, my left hand, robot like, joined my right. I remember some flashing, and pain, but that’s it. My brother unplugged me. In the following days I had much difficultly walking, and developed a great fear of electrical appliances. No superhero strengths, as I hoped. If that device was grounded, that would have never happened.

Another grounding story: There was a kid in my school, he was couple years younger. I think his name was Brad, doesn’t really matter, he’s dead. He was swimming at a lake, and was electricuted when he grabbed the railing of the dock. If the railing was bonded to ground, as is now required by that silly feel-good code, he’d be alive today.

Once again I ask, does anyone know what personal liability one assumes when they circumvent the ground prong?

Those 2-3 adapters are safe when used correctly. Next time you’re at the store, pick up a bubble packed one and reading the warning/installation instructions on the back of the card.

As for cutting the third prong off, that’s triply bad. One, you’re defeating the ground, two, you’re defeating polarization of the other two prongs, and three, your modifying the device, voiding any warranties, and any other consumer protections.

26

So, what are you saying - I SHOULDN’T stick my finger in this socket?

27

It might also violate home-owner’s insurance, so try not to start a fire via this method …

28

I agree, but here’s the deal:

If you have a 2-prong outlet, and if the metal box is grounded, then why not simply install a regular 3-prong outlet? That’s what I would do. An outlet only costs a $1 or $2, and takes about 10 minutes to install. But the second “if” is the biggie… if you have a 2-prong outlet, chances are a ground wire was not run to it. If this is the case you have 3 long-term options: 1) Don’t plug a 3-prong appliance into it, 2) run a ground wire to it and install a 3-prong outlet (this is best, but is usually a pain in the ass to do), or 3) install a GFCI outlet.

29

Crafter_Man,

I agree with you 100%. I would, and do replace 2 prong sockets with three prong sockets, providing the box is grounded. I view those devices as useful for people without the aptitude, interest, or ability (such as renters) to do such an upgrade. My house is great since I have both a subfloor and attic. I can home-run ground leads back to the breaker panel fairly easily, it was better prior to 1994, when you could bond to any water pipe, with the pipe bonded to the ground, but it’s for the better I know.

You mentioned that GFCI devices are notoriously unreliable, I’ve never heard that. Of course comparing our usernames: Crafter_Man vs. NotMrKnowItAll, I’m not surprised by that. What’s the skinny on this?

30

I’ve never heard of a GFCI not tripping when it was supposed to, but I’ve seen several cases of a GFCI nuisance tripping. This is most common after a lightning storm, as Crafter_Man mentioned.

The oddest one I’ve seen was a modern house where a downstairs kitchen GFCI tripped every time a certain upstairs toilet was flushed :slight_smile: I witnessed this happen, but wasn’t able to stick around to find out the cause (presumably a grounding issue with a water pipe vibrating, although the house was mostly plastic plumbing).

Arjuna34

31

I certainly don’t have statistics, nor do I believe they exist. But ask yourself this question: Why do they tell you to test your GFCI’s once a month?

I can also relate some personal experience. In the previous lab I worked in, we had 4 GFCI’s along one wall. During a routine inspection, we found one that was bad. At the previous home we lived in, the inspector noted that the GFCI beside the sink was bad. I have heard similar stories from others. In each case, the bad GFCI continued to operate “normally,” though there was obviously no ground fault protection.

One of the most common failure modes is a failure of the MOVs inside the GFCI. And it’s not fail safe; failure of the MOVs will allow you to use the outlet, yet it will provide no protection. And you won’t even know it’s a dead horse until you test it. It’s believed that lightening strikes take out the MOVs, and at least one GFCI manufacturer has come out with a design that has solved this problem.