Resolved Which way to go from 3 pronged to 2 pronged cord?

I have a laptop adapter that has a 3 pronged plug. My extension cord has a 2 pronged outlet.

I just bought this: http://www.target.com/p/ge-grounding-adapter-polarized-2-pk/-/A-14442316#prodSlot=medium_1_1&term=grounding+adapter


Is there any reason why this would not/might not work with my computer---as in, could it damage the computer in any way?

 

You have lost one of the most important things doing this. No Ground. They do make extension cords that are 3 way as I have some 6 ft. ones that I use at Christmas time for the outside lights in front of the house.

 

It will work and will not cause damage just by now being 2-prong. But as MrBill correctly noted, there is now no dedicated ground. So you have lost a major safety capability - especially if the facility wiring is not otherwise up to code.

My advice it to get a 3 conductor extension cord as MrBill suggested. They come in all sorts of lengths and are available at most discount and all home-improvement stores. 3 conductor cords tend to be of larger gauge too - which is better for longer length cords.

But I have to ask, why did you get that adapter? If it is because your wall outlet is 2 prong, then clearly it must be old - very old and ultimately should be properly upgraded by a qualified electrician.

In the meantime, see that little green loop thing at the bottom of the adapter? That is designed so when the adapter is plugged into the wall outlet, you can use the faceplate mounting screw to secure the adapter to the wall outlet. This has the intended purpose of grounding the adapter to the outlet box inside the wall - a good thing. Just make sure the mounting screw is not covered in paint. It needs to be bare metal. This is not ideal, but better than no ground at all.

Ideally, the outlet boxes inside the walls are grounded to "Earth" ground through a 3rd wire running through the walls to the service panel, then out to Earth ground. If there are 3 wires running through the walls, then I recommend replacing the outlet socket with a new outlet.

In some cases with older buildings, the box gets its Earth ground through metal conduit - but this generally is not that good as the conduit connections become loose over time. Alternatively, the box could be grounded by a 3rd wired (specifically a ground wire designed for grounding) that is "bonded" to the "cold" (never hot) copper water delivery pipes running in the walls. This also is generally not that good because the plumbing in older homes is often repaired or modified and continuity to Earth ground is disrupted by poor solder joints in the piping, or sometimes plastic PVC pipes are used in upgrades or repairs - breaking the link to Earth ground.

 

I got it because the extension cord that I have is 2 pronged on both ends, but my laptop adapter has a 3 pronged plug. The wall itself is 3 pronged (at least the one I'm trying to connect to now).

I bought a 3 pronged cord as well, but as the adapter was cheaper, I thought I'd give that a shot. OK I'll pay a few bucks extra and go with safety.

 

Aren't 2 pin plugs used on electrical appliances that are Double-insulated???
You don't get the electric shock if there is a short in the device because of the RCD type switch connection in the device trips out quicker than an earthed unit which is live and blows the circuit breaker at the board.
There is less chance of getting fried with a Double-insulated unit. Neil.

 

Yes, but those are "polarized" plugs - one is bigger than the other so they can only go in the wall outlet one way. And they work on the assumption the outlet is properly wired.

But, since this notebook adapter uses a 3 prong, it is either not polarized (not likely), it uses the 3rd wire to ensure a proper ground, and/or it uses the 3rd wired to shunt potential RFI/EMI (interference) to ground, and/or to help establish a "common ground" when connected to other powered devices. Since notebooks are designed to connect to external monitors, Ethernet networks, and more, I am going to assume the primary reason for using a 3-wire power cord is primarily for safety and interference suppression by creating that common ground to eliminate any "difference of potentials" between the devices (a common problem when interconnected devices get their power through different outlets).

 

Bill, I checked around the house and found numerous 2 pin plugs on household appliances eg, vacuum cleaner, vacuum duster units with transformers, portable radios, stalk electric mincers.
We are talking 240 volts here in NZ. Neil.

 

Most are. We have that here in the states also. Houses built since the probably 60's are 3 wire in the wall. Blenders, vacuums, coffee pots and a lot of other stuff don't need the 3rd wire ground and only come with the 2 wire plugs. If something has the 3 wire plug, it should be plugged into a 3 wire outlet.
Most of our stuff in the states is 110 at the house except for things like the hot water heater, stoves and AC/Heat units especially central AC/Heat.

 

Another thing to consider is if the device can be connected to other powered devices. You don't plug in other devices into your coffee pot or vacuum cleaner that may not be double-insulated or be vulnerable to noise interference.

My hot water heater is gas so no big electricity draw there and the controller uses a 110VAC to 24VDC transformer. Same with my forced air furnace. The blower motor is 110VAC too.

My clothes dryer is 220VAC and so is the AC compressor outside, as is the kitchen oven. But that's it in my house.

As far as your two prong appliances down in NZ, are the plugs all polarized too? That is, can they only go in one way? This ensures the neutral wire always goes to the neutral connection in the wall outlet and the "hot" wire always go to the hot side of the outlet.

 

These links will show what we have in NZ and Australia:http://www.worldstandards.eu/electricity/plugs-and-sockets/i/
http://www.energysafety.govt.nz/consumer/safe-living-with-electricity/electrical-equipment-and-appliances/plugs

https://en.wikipedia.org/wiki/AS/NZS_3112
I think from what info is available - the safety rule is that when 3 pin cables are used in appliances, that an extension cable should be 3 pin male and female.
A 2 pin cabled appliance can be plugged into 3 pin extension cable.
I have never seen or come across a 2 pin (male / female) extension cable in NZ.

 

And yeah, those two pin plugs can only be plugged in one way to ensure proper polarity. Interesting to read those two pin plugs are an obsolete American type.

 

What's more interesting is the fact that there is NO World universality of electrical connectors!!! When travelling Worldwide, you need to have adaptors for your shaver and then, if you happen to go to Ireland and visit a certain Hotel in Waterville, you will find 3 (Three) different wall sockets in one room!!!
Only in Ireland 'to be true' 'to be true' could you find this scenario and the only wall socket I could use was the TV one.
So imagine me sitting on the floor behind the TV shaving by feel/touch as I didn't have a mirror!
I needed this as my re-chargable shaver battery was flat.

 

They have been for years. Lots of our appliances are 2 prong and can only be plugged in one way unless you cut down one side of the plug than it can be plugged on anyway.

 

Being retired military, I have lived in 4 different countries and spent time in about 10 more and it always amazed me how many different "standards" there are.

I can see there being 2 or 3 around the world, but there are dozens. Even across Europe there are several. And some countries use different standards in the same country (Brazil for example). It would just cost way too much to convert everyone to the same standard. Many governments could not afford it, and neither could many businesses or individuals afford to convert their workplaces and homes, and all their electronic devices too.

And of course, it is not just voltage, but current. We use 60Hz here in the US, most of Europe uses 50Hz. Fortunately, this is less a problem as more and more devices run off DC.

Just getting the world to settle on a single standard would be impossible. While it would be better and safer if all countries used 220VAC throughout our homes and offices, no way that is going to happen.