Using 2 prong outlets safely in a 3 prong world?
August 4, 2015 10:15 AM Subscribe
I'm moving into a house that is almost entirely 2 prongs. Sure there are 3->2 prong adapters. But is there a safer way to use these outlets without tearing up the walls? Are there any relevant safety gadgets out there?
Best answer: You don't want to just use a plug-in adapter- you will not be grounded. (Those adapters aren't even legal in Canada, I just found out!) However, it may be possible to replace the plugs without ripping up the walls.
posted by showbiz_liz at 10:19 AM on August 4, 2015 [1 favorite]
posted by showbiz_liz at 10:19 AM on August 4, 2015 [1 favorite]
Best answer: Get a $5 outlet tester just to be sure.
... if you're sure you know how to use it. It's not rocket science but, I mean, it is high-voltage electricity.
Really I would recommend hiring an electrician to come out just for an hour (for maybe $100? Depending on where you live) and testing whether your outlet boxes are in fact grounded. If so, you can get some grounded outlets at Home Depot or equivalent and replace the 2-prong ones for under $20 apiece. As stoneweaver points out, you may be able to get away with one per room.
If your kitchen and bathroom are also only 2-prong, that's almost certainly not up to code anywhere in the US and is actually a safety issue. You should really upgrade those with ground-fault interrupter outlets (a/k/a GFI or GFCI). Those are worth upgrading to properly grounded even if they are completely lacking grounding at the moment.
posted by Joey Buttafoucault at 10:39 AM on August 4, 2015 [1 favorite]
... if you're sure you know how to use it. It's not rocket science but, I mean, it is high-voltage electricity.
Really I would recommend hiring an electrician to come out just for an hour (for maybe $100? Depending on where you live) and testing whether your outlet boxes are in fact grounded. If so, you can get some grounded outlets at Home Depot or equivalent and replace the 2-prong ones for under $20 apiece. As stoneweaver points out, you may be able to get away with one per room.
If your kitchen and bathroom are also only 2-prong, that's almost certainly not up to code anywhere in the US and is actually a safety issue. You should really upgrade those with ground-fault interrupter outlets (a/k/a GFI or GFCI). Those are worth upgrading to properly grounded even if they are completely lacking grounding at the moment.
posted by Joey Buttafoucault at 10:39 AM on August 4, 2015 [1 favorite]
showbiz_liz has it -- I moved into a house like that, and while the electrician was not cheap (and maybe you can do it yourself), no wall-tearing was required.
posted by JanetLand at 10:42 AM on August 4, 2015
posted by JanetLand at 10:42 AM on August 4, 2015
If your home does not have metal armored cable (most do not), then it might be quite expensive to rewire your home with a ground wire.
An alternative is to install Ground Fault Circuit Interrupter (GFCI) outlets in place of your current outlets. These are pretty cheap, about $10 per outlet and you can do it yourself if you are experienced in electrical work.
The GFCI will provide electrocution protection, but it does not actually provide a ground connection, so it may cause minor problems with some electronics -- noise, interference, etc. The GFCI package should include a small stick-on label "No Equipment Ground" that you should put on the outlet. This is to let everyone know that, while the GFCI protects the two power prongs, it doesn't connect the third prong to a ground.
One thing you might consider. No homes had three-prong outlets for the first 60 years of electrification. And your home probably was built before the 1960s and worked with two-prong outlets all of the time since. Your two-prong outlets are no less safe than they were in millions of homes before 1960. They are not as safe more modern grounded systems.
posted by JackFlash at 10:57 AM on August 4, 2015 [1 favorite]
An alternative is to install Ground Fault Circuit Interrupter (GFCI) outlets in place of your current outlets. These are pretty cheap, about $10 per outlet and you can do it yourself if you are experienced in electrical work.
The GFCI will provide electrocution protection, but it does not actually provide a ground connection, so it may cause minor problems with some electronics -- noise, interference, etc. The GFCI package should include a small stick-on label "No Equipment Ground" that you should put on the outlet. This is to let everyone know that, while the GFCI protects the two power prongs, it doesn't connect the third prong to a ground.
One thing you might consider. No homes had three-prong outlets for the first 60 years of electrification. And your home probably was built before the 1960s and worked with two-prong outlets all of the time since. Your two-prong outlets are no less safe than they were in millions of homes before 1960. They are not as safe more modern grounded systems.
posted by JackFlash at 10:57 AM on August 4, 2015 [1 favorite]
I've rewired a couple of 1950's vintage houses (1953 and 1958, I think), and in both cases, three-wire cables were used and the boxes grounded, even with two pronged plugs used. It's worth checking if this is the case. If so, all you need to do the upgrade is a box of three-pronged plugs and some pigtails.
Do the switches while you're at it too.
posted by bonehead at 11:12 AM on August 4, 2015
Do the switches while you're at it too.
posted by bonehead at 11:12 AM on August 4, 2015
Standard "don't mess with electricity unless you know what you're doing and being 100% safe" disclaimer.
miyabo's info is correct. A properly installed 2-prong outlet will be in a grounded metal box. The adapter has a screw hole aligned so that when you screw it into the center face-plate screw, you are creating a connection to the box, and therefore to ground. Indeed a tester will show you if it's grounded. This kind of tester is pretty much foolproof, as it just plugs into your 3-prong outlet or adapter and shows you the status with lights.
My house was built in 1961 and most of the outlets are (were) two-prong. It was not terribly difficult to replace them all with 3-prong grounded outlets. It's time consuming, but there is no wall-ripping required. You replace the 2-prong outlet with a 3-prong one, and wire the ground on the 3-prong outlet to the metal box. The outlet tester mentioned above will tell you if everything is right.
That's the short version. Since you are asking this question, I'll assume you haven't done much with electrical wiring, so I suggest getting a quote from an electrician, who can do it much quicker than you and spot any other potential trouble.
But as JackFlash says: 2-prong outlets are not automatically dangerous. I would say 90% of everything I plug in only has a 2-prong plug, anyway. All of my audio and video equipment is 2-prong, and all of my lamps. Even some of my power tools are only 2-prong. I changed out my living room mostly as a matter of convenience rather than "safety."
posted by The Deej at 11:14 AM on August 4, 2015
miyabo's info is correct. A properly installed 2-prong outlet will be in a grounded metal box. The adapter has a screw hole aligned so that when you screw it into the center face-plate screw, you are creating a connection to the box, and therefore to ground. Indeed a tester will show you if it's grounded. This kind of tester is pretty much foolproof, as it just plugs into your 3-prong outlet or adapter and shows you the status with lights.
My house was built in 1961 and most of the outlets are (were) two-prong. It was not terribly difficult to replace them all with 3-prong grounded outlets. It's time consuming, but there is no wall-ripping required. You replace the 2-prong outlet with a 3-prong one, and wire the ground on the 3-prong outlet to the metal box. The outlet tester mentioned above will tell you if everything is right.
That's the short version. Since you are asking this question, I'll assume you haven't done much with electrical wiring, so I suggest getting a quote from an electrician, who can do it much quicker than you and spot any other potential trouble.
But as JackFlash says: 2-prong outlets are not automatically dangerous. I would say 90% of everything I plug in only has a 2-prong plug, anyway. All of my audio and video equipment is 2-prong, and all of my lamps. Even some of my power tools are only 2-prong. I changed out my living room mostly as a matter of convenience rather than "safety."
posted by The Deej at 11:14 AM on August 4, 2015
Get a $5 outlet tester just to be sure.... if you're sure you know how to use it. It's not rocket science but, I mean, it is high-voltage electricity
The kind of outlet tester you should get looks like this. You plug it into an outlet, see what lights up, and look it up on the table printed on the side of it. It's pretty much the least dangerous thing you could possibly plug into an outlet.
posted by aubilenon at 11:22 AM on August 4, 2015 [3 favorites]
Best answer: The saying goes: Ground protects equipment, GFI protects people.
Switch to GFI outlets in wet areas to protect humans. GFIs function without being grounded.
Note that wiring a 3-prong outlet to the metal outlet box does nothing if armored cable (greenfield) isn't used connecting the box itself to ground. Armored cable is relatively uncommon in residential construction.
posted by LoveHam at 11:24 AM on August 4, 2015
Switch to GFI outlets in wet areas to protect humans. GFIs function without being grounded.
Note that wiring a 3-prong outlet to the metal outlet box does nothing if armored cable (greenfield) isn't used connecting the box itself to ground. Armored cable is relatively uncommon in residential construction.
posted by LoveHam at 11:24 AM on August 4, 2015
Best answer: I rewired most of my (1953) houses two-prong outlets into grounded three-prong outlets. A few things I found helpful:
Before I did anything else, I bought one of these to check whether the box was grounded in the first place. It's not quite as idiot-proof as the outlet tester others have pointed at, but then I knew whether or not to buy a couple dozen outlets and grounding wires.
Buy the grounding wires with the screw already attached. So much easier.
A headlamp makes it much easier to see the back of the electrical box and find the hole for the grounding screw with only two hands.
The wires are seriously stiff, needle-nose pliers are super-helpful.
Honestly this is not rocket science, it's just tedious. If you have basic competency with wires and screwdrivers, you can do this for ~$3-$4 an outlet. Many electricians will charge an extra $10-$20 on top of that, but if you have more money than patience/confidence, that's a perfectly valid choice.
posted by contrarian at 11:56 AM on August 4, 2015
Honestly this is not rocket science, it's just tedious. If you have basic competency with wires and screwdrivers, you can do this for ~$3-$4 an outlet. Many electricians will charge an extra $10-$20 on top of that, but if you have more money than patience/confidence, that's a perfectly valid choice.
posted by contrarian at 11:56 AM on August 4, 2015
Is this a rental house? I've successfully demanded the landlord replace the outlets before, and was ready to cite some obscure(that did not necessarily apply but i planned on vaguely representing it) city code bit/rental rules but never even had to.
I'd definitely go down that route if you're just renting the place before i bothered with anything else.
posted by emptythought at 1:21 PM on August 4, 2015
I'd definitely go down that route if you're just renting the place before i bothered with anything else.
posted by emptythought at 1:21 PM on August 4, 2015
Response by poster: Unfortunately this is a 1959 home that I just purchased. And because it is here in SF Bay Area, it costs $1 trillion dollars, is in bad condition, and someone died in it. (Related.) I've been told an electrician will run $200+ per hour. Good contractors are impossibly hard to find, and when they find out you don't work for Google/Facebook/Apple they hang up on you, which is probably just as well since I can't afford them.
Lots of good reading here! Thanks.
posted by Mushroom12345 at 1:31 PM on August 4, 2015
Lots of good reading here! Thanks.
posted by Mushroom12345 at 1:31 PM on August 4, 2015
My house (in CT,) is from the same era. Yours is likely wired with (I forget the proper name) a couple wires inside a metal cover. The cover should grounded. The junction boxes will be metal, and grounded to that metal cover. As described, its not hard to change the outlets.
When I installed GFIs in my bathrooms, I was confused until I realized that the enclosed directions didn't apply. The wire that has long since replaced the metal covered stuff has three wires in plastic.
If you do call an electrician you might ask about upping the e!ectrical service and running a new circuit or two to the kitchen and/or utility room and/or garage.
posted by SemiSalt at 1:51 PM on August 4, 2015
When I installed GFIs in my bathrooms, I was confused until I realized that the enclosed directions didn't apply. The wire that has long since replaced the metal covered stuff has three wires in plastic.
If you do call an electrician you might ask about upping the e!ectrical service and running a new circuit or two to the kitchen and/or utility room and/or garage.
posted by SemiSalt at 1:51 PM on August 4, 2015
Unless I'm mistaken, you could also replace the circuit breaker in the electrical panel with one with ground fault protection. It's a little more inconvenient if the GF trips, since you need to reset it at the panel instead of the outlet, but it would cover the entire circuit run.
posted by sapere aude at 1:52 PM on August 4, 2015
posted by sapere aude at 1:52 PM on August 4, 2015
The problem with a panel gfi, as I understand it, is that the overcurrent still travels through the wires in walls back to the panel before the circuit pops. Everytime that happens the fire risk from the newly work-hardened wires and insulation increases--not as much as a slower regular breaker, but still.
Better to have the ground fault protection in the receptacle so that it can trip immediately and protect the house wiring. Lower fire risk. Costs a bit more, but safer.
posted by bonehead at 2:13 PM on August 4, 2015
Better to have the ground fault protection in the receptacle so that it can trip immediately and protect the house wiring. Lower fire risk. Costs a bit more, but safer.
posted by bonehead at 2:13 PM on August 4, 2015
If the house was built in 59 I would definitely get an electrical inspection. Mine was built in 1958, 3400 sf, cost 1700 to make things right.
posted by Mr. Yuck at 4:21 PM on August 4, 2015
posted by Mr. Yuck at 4:21 PM on August 4, 2015
Best answer: The Deej: "A properly installed 2-prong outlet will be in a grounded metal box."
There are a lot of installs that were done properly at the time that are not grounded at the box. Plus the older the installation the greater the chance that "Bob the I don't know jack and I don't care handyperson" has messed up the ground path. Test every outlet.
The Deej: " This kind of tester is pretty much foolproof, as it just plugs into your 3-prong outlet or adapter and shows you the status with lights."
Be aware there is a way of tricking those testers to show "all is well" when really there isn't a ground path. Having an electrician visit, even for a couple hundred dollars, for an inspection would be money well spent.
bonehead: "The problem with a panel gfi, as I understand it, is that the overcurrent still travels through the wires in walls back to the panel before the circuit pops."
GFIs do not protect against over current conditions (well a GFI breaker will of course but it is the breaker section that is providing the protection not the GFI circuitry). A wall GFI will not trip because of over current. GFIs function by detecting a difference in current flowing through the hot and neutral conductors and interrupt the current flow if the difference exceeds a set amount (usually a few milliamps).
Because a receptacle style GFI can be configured to protect all down stream devices and because they cost $10 vs the GFI/breaker combo prices of 50-150 dollars or more you usually see only the wall GFI unless there is a compelling reason to install protection in the panel.
posted by Mitheral at 8:31 PM on August 4, 2015
There are a lot of installs that were done properly at the time that are not grounded at the box. Plus the older the installation the greater the chance that "Bob the I don't know jack and I don't care handyperson" has messed up the ground path. Test every outlet.
The Deej: " This kind of tester is pretty much foolproof, as it just plugs into your 3-prong outlet or adapter and shows you the status with lights."
Be aware there is a way of tricking those testers to show "all is well" when really there isn't a ground path. Having an electrician visit, even for a couple hundred dollars, for an inspection would be money well spent.
bonehead: "The problem with a panel gfi, as I understand it, is that the overcurrent still travels through the wires in walls back to the panel before the circuit pops."
GFIs do not protect against over current conditions (well a GFI breaker will of course but it is the breaker section that is providing the protection not the GFI circuitry). A wall GFI will not trip because of over current. GFIs function by detecting a difference in current flowing through the hot and neutral conductors and interrupt the current flow if the difference exceeds a set amount (usually a few milliamps).
Because a receptacle style GFI can be configured to protect all down stream devices and because they cost $10 vs the GFI/breaker combo prices of 50-150 dollars or more you usually see only the wall GFI unless there is a compelling reason to install protection in the panel.
posted by Mitheral at 8:31 PM on August 4, 2015
This thread is closed to new comments.
posted by miyabo at 10:19 AM on August 4, 2015