three prong adapters

My SO, when faced with the problem of a three prong plug and a two prong outlet, uses one of those three prong adapters. Is this safe? It seems unsafe to me. What could happen? What are the risks?

Second question: The three prong adapter comes with a little grounding wire. Is this wire supposed to be connected to the little screw in the center of the outlet? If I do this, am I safe? Or do I need to run a wire from the grounding wire to, say, a radiator?

If it makes a difference, the three prong adapter will be run to a power strip which is used to power a computer; monitor, and printer.



This is not safe, at all, and especially not safe with a power strip and computer. Get an electrician to install a properly grounded outlet, or move the computer.

An “adapter” is just an adapter. I.e., it just allows you to plug a three prong plug into a two prong receiptacle. It does not provide ground or anything else by itself.

If your outlets are wired right, and if the box is connected to ground (as it should be), and if you hook up the grounding wire, and if it’s in a place where it doesn’t present any increased danger of the plug getting pulled out partway, then it’s as safe as a real three-prong outlet. If all those conditions are not met, it’s not as safe, and specifically, if there’s no true ground set up (wire not attached to the screw or electrical box not grounded) then you’re just asking for trouble.

New outlets are under five bucks, and it’ll be the minimum charge for the electrician’s time. It’s worth it to just get new outlets.

Thanks for the speedy replies.

A few followup questions:

First, what risks am I actually taking? I can turn the power strip off when it’s not in use.

Second, I have attached the little wire to the little screw. Is there anyway I can check to see if the “electrical box” or outlet cover is properly grounded?

Third, what risks are there if the plug comes out part way? (It would be easy enough to put a block under the plugs.)
Thanks again.

P.S. I agree that having an electrician install three-prong outlets would be a good solution, but I rent, and it would be a lot of agita. I’d rather just run a wire from the “ground” wire of the three-prong adapter to a radiator (assuming that is safe)

If the entire house/apt is wired old way, 2wire, no adapter can change it, onle rewiring will help. You can ground your PC/whatever to a radiator, it will do the trick, especially if you doublecheck the radiaror with a special device wich de`termines/confirms grounding. Go to a specialized big electrical retal/wholesale outlet frequented by electricians/contractors, it will be able to help you. I know that there are test-plugs which can test an outlet for grounding, but you need something else. A pro electrician will likely to tell you that grounding a PC through a radiator is extremely dangerous. Tell him that you realize this, you always has been an adventurist, like the thrill. :-).

I’ve had quite a bit of experience with ungrounded computer systems, both 220V and 110V. Although I worry about damage to the computer, printer, monitor, etc. I have never had any damage I could attribute to using an ungrounded plug. What I have had is annoying tingling feelings when I touch the computer case. In one house, I had no convenient ground so I drilled a small hole through a window sill, ran a copper wire through it to the outside, then ran about 8 feet of stripped wire through a shallow trench to a metal fence with multiple metal posts stuck in the earth. That seemed to do the trick and didn’t hurt the chickens. Currently, several of my 6 computer systems are in rooms with ungrounded outlets wired with only two-conductor wires. I haven’t had any problems but I do plan to ground them someday, somehow.

I think the little yellow thing with 3 prongs and 3 lights that is sold for a few bucks at hardware stores will tell you whether you have a functional ground or not.

Yeah, it will, but he can’t plug it into 2hole outlet. A PC or anything else will work (perhaps, forever) with no problems in 2wire system (in 110v system, one wire is the ground!). 3wire system offers a safety feature, like a seat belt.Except you don’t have to get into a crash, a disaster may happen sooner. But then, it’s only a cheap computer, who cares.

Are your outlets polarized, so that you can only plug a plug in one way? If so, it’s probably wired correctly (so the hot blade is on the right, and neutral on the left, if you face the outlet), and you are probably ok with the adapter (provided you don’t plug it in upside down). You should still connect the adapter ground wire to true ground (a radiator would be better than the center screw of the outlet, if you’re willing to go to the trouble).

If your outlets are not polarized, you probably shouldn’t count on anything. You should have an electrician check out the wiring. As someone else mentioned, just changing the receptacle isn’t sufficient if there isn’t a ground wire in the box. The danger if the outlet is wired backwards is that the PC chassis will be electrically hot- you’d get shocked if you touched the metal chassis while grounded. You’d have a dead short if you plugged a printer into the parallel port, if the computer and printer plugs were plugged into differently (a good reason for polarized plugs).


Also, the small outlet testers can’t check for all possible wiring errors on an outlet, especially if you use a 3-prong adapter to plug it into a 2-prong outlet!


just so I’m clear, if the outlets in my apartment are polarized (which they are) the only danger is that my computer will be damaged?

If you have 2-slot outlets, they’re old, but you have a good chance of having BX cable (the kind with the spiral metal sheath). You can find out by taking off the cover and looking for the place where the wire enters the box. If it’s BX, you’ll see the sheath and the clamp that holds it to the box. The sheath itself is the ground.

Assuming the panel end of the BX cable is connected to the main ground, you can make a grounded outlet by using the little green wires from Home Depot or Lowe’s with a screw on one end. Put the screw into a hole on the box (there’ll be a couple), and the wire end on the ground screw of a new 3-prong outlet. Put the hot wire on a gold screw, and the neutral on a silver one, and you’re grounded.

But I’m keeping my real identity secret in case you burn your house down anyway.

Even if you have grounding at the plug, and everything is wired correctly, I’m not sure how safe it would be. I have one of those, and the little wire which you can hook up to the screw is pretty thin. You’d be fine as far as discharging static, but if you had a short where 10 - 15 amps were running through the tiny little ground wire, I’d be worried.

If grounding is there, you can put in (or have put in) a three prong plug. If there is no ground at the outlet, you can put in a GFCI outlet (about 10 dollars U.S.). You won’t have a ground, but you will have electric shock protection. This is allowed under code as long as you put on a sticker which says the outlet is not grounded.