I’m about to replace some worn out receptacles in my 55 year old ranch. I’ll be replacing the old style 2-prong receptacles with 3-prongs (can’t find 2-prong locally) and putting the little labels on each that states “No equipment ground” on each new receptacle. , I will be placing a GFCI (in series) in the first receptacle in each branch circuit to protect the remainder of the receptacles on that branch.
My thought is – as a safety measure why not tie the resulting empty ground in each new receptacle to the neutral in that receptacle? This would provide an effective ground at each new receptacle since neutral and ground are bound together at the main breaker box.
Perhaps I’m missing something here – you would have to be CERTAIN that you didn’t have a branch circuit with reversed hot and neutral (and I always check this), but if you were certain – would this be a bad idea?
As a further complicator, would this defeat the upstream GFCI protecting the branch?
Mike D
Edited 11/25/2009 4:13 pm ET by Mike_D
Replies
What you describe is commonly known as a "bootleg ground", and it is a bad idea. Try Googling it.
The general consensus is that a bootleg ground is worse than no ground at all. Stick with your GFCI receps and the labels. Be safe.
Here's a bit of commentary from another forum:
Suppose you have some appliance that uses a three-prong plug (e.g., a refrigerator or a computer). Now further suppose that that appliance is plugged into a receptacle with a bootleg ground (i.e., grounding hole on the receptacle is connected to the neutral wire). Now suppose that neutral wire becomes disconnected someday, at any point between this receptacle and the panel. Any regular reader of this forum knows that open neutral problem are reported on this forum every day. They are quite common.
When that neutral opens, the case of the appliance will now have a full 120 volts on it. This happens since the case is connected to the ground wire, and the ground wire is connected to the neutral at the receptacle, and the neutral wire is connected to the hot wire through the load and there is no voltage drop through the load since no current is flowing. The breaker will not trip.
Next person who touches the case of that appliance is seriously injured or dead, depending on the resistance of their skin and how well they are grounded.
Edited 11/25/2009 4:24 pm by Scott
Great replys, thanks!
I'm really glad that I asked - and it seemed like such a good idea, too - so logical :)
Sooooo, I won't be doing that.
Mike D
P.S. I do routinely scan Breaktime, and I've not noticed threads on open neutrals - so what causes open neutrals so much that they are a common occurance?
>>>so what causes open neutrals so much that they are a common occurance?I wouldn't say they are a common occurance (that was another guy's commentary that I posted), but they do happen. Problem is, when they do happen, they can cause all kinds of havoc, especially if it's the main service neutral that opens.
yesterday i had one, the screw on the plug had loosen up,so i had a intermitent break. everything flickering. once it gets loose,then it arcs and create heat.
the 2 prong new plugs,lowes has them about 2 bucks each.the older i get ,
the more people tick me off
Not a good idea.
Post _____.2 tells you why.
Jim
> As a further complicator, would this defeat the upstream GFCI protecting the branch?
Yes. GFCI works by comparing the current going out on the hot with the current returning on the neutral. If they're different, it trips. If current leaks into the ground, there's less on the neutral, which is supposed to trip the GFCI. But if you put that current back into the neutral, it won't trip.
What's inside the walls? Conduit, flex, romex, loomex, ....?
-- J.S.
Not entirely.GFCI is aimed at personal protection, detecting faults.If there is any current through a person to a ground then it will still trip.If metal cased appliance with a grounding pin and a bootleg ground then leakage current in the device might not trip the GFCI which it would if it had a true ground. And might not trip if someone grabs it and is grounded as most of the leakage current will be going through the neutral.But if there was enough leakage current through the person to be safety hazard then the GFCI would still trip..
William the Geezer, the sequel to Billy the Kid - Shoe
Actually, it WILL trip, as soon as you grasp the "grounded" device. Ground current will flow through your body and trip the GFCI.
A strong nation, like a strong person, can afford to be gentle, firm, thoughtful, and restrained. It can afford to extend a helping hand to others. It's a weak nation, like a weak person, that must behave with bluster and boasting and rashness and other signs of insecurity. --Jimmy Carter
You can find 2-prong outlets, and they're preferred to the labels (though a GFCI is still a good idea). I've seen them at the local HD and a few other places (though the color choice is apt to be limited).
As stated, a "bootleg ground" to the neutral is generally not a good idea -- there are scenarios where it's dangerous.
(And the bootleg ground would cause the upstream GFCI to trip.)
Doing so would most certainly make the GFI useless.