My latest Toshiba laptop’s AC adaptor has a grounded plug. It cannot be required by the computer since it can work without a cord. I know that there are no grounded sockets in Japan, where they design (and make?) them. This is an incovenience to me since I plug it in in various locations and it is a pain to move the plug. I have another power adapter that is not grounded. Is there any possible harm from using it?
The old one is 19V, 3.16A, while the new one is 19V, 3.42A, which seems close enough to me. Does anyone know if there is any problem with this?
The purpose of a grounded plug is so your chances of being electrocuted by mains voltage is greatly reduced. When your laptop is running solely on its battery, it’s not connected to mains power so potential electrocution no longer exists.
An engineer should come along shortly to explain if swapping external power supplies with the different ratings you stated might be harmful (or not) to your computer.
My house is pre - three prong outlets. I bought about a half dozen three-prong adapters (such as Duckster has linked to) when I first moved in. But those damn things have a way of disappearing. I recently went out to the Home Depot and bought one for every outlet in my house plus an extra handful. Now I just have one always stuck in every outlet so I don’t have to worry about three prongs ever again. My advice to you is to just duck tape a three-prong adapter onto your powercord. Now if Hari and I don’t ever post again, apparently we were electrocuted.
If you were using them correctly, this wouldn’t happen. You’ll notice each one has a (usually green) metal tab with a hole in it. You’re supposed to remove the cover plate screw from the outlet, plug in the adapter and then replace the screw through the adapter’s tab. The reason for this is, unless your house is very old, the metal outlet box is supposed to be grounded; the adapters aren’t supposed to be a way of circumventing the ground, it’s meant to provide an alternate means of supplying one.
Shouldn’t be. A voltage supplied by the two power supplies is the same, and the max amp draw of the new one is higher than the old one, so no problem there. The next issue is that the laptop end of the plug both fits, and is the correct polarity.
Eectrocuted by the power converter? No more likely than it ever was and I’ve not heard of any spate of electrocution either here or in Japan. I will check on the polarity, but I doubt if it is different. My only question is if anyone knows whether the computer is grounded.
When I got my first computer in April 1982 (a genuine IBM-PC with unnumbered PC-DOS–retroactively called 1.0), the guy who sold it to me said he would refuse to look at any machine not properly grounded. Presumably, it could be flaky, but I don’t see how a laptop could be.
Sprry to post again so soon, but I just looked at the diagram on the power converter and it shows just two connectors coming out with the inner one positive and the outer one negative. So I guess I have answered my own question.
QED,
We don’t have grounding screws in our electrical outlets here. They’re just polarized 2-prong outlets. I checked the building supply shops and, yes, 2-prong outlets are the norm here. My washer/dryer, fridge, and air conditioner plug into these outlets, and the rest of my appliances are gas. I’ve not seen anything a consumer would have in his home that requires a grounding plug. Yes, I’m a nerd; I look at power cords when I hit the Best Buy-like stores here.
Dell includes this adapter with its laptop power supplies destined for Japan. Plug the “Mickey Mouse” end into the power brick then any standard 2-wire cord into the other.
[rant] 3-prong cords are a major pain here. It’s hard finding the adapters and they’re frequently too large to fit on power strips. Or desktop outlets at hotels. They tease us by putting the outlets right on the riser at the back of the desk, so I don’t have to crawl around under the desk, but too close to the desktop to fit an adapter. Dammit. I hate 3-prong cords! [/rant]
Sorry, I keep forgeting that international language support isn’t native to Windows. I live in a small town in northern Japan, Aomori prefecture. About 400 miles north of Tokyo and one local train stop past the end of the bullet train. Tying this into the electrical OP, I’m on the 50hz side of the island.
My laptop came with an adaptor with a three-pin AC side, with a suitable UK 3-pin plug at the end of the lead, and also separate leads which ended with European and American two-pin plugs.
I’m not sure if that proves or demonstrates anything, but hey. At least when my dad moved to America, all he needed to use his Dell over there was to borrow/steal one of those leads.
Just a WAG, but it could have something to do with reducing EMI radiated from the power supply and/or computer. In many cases, shielding works better when it’s connected to earth ground.
Gorilla,
Is the grounding pin on the UK 3-pin plug metal or plastic? If it’s metal, we may have come to a probable cause. The UK’s electrical regulator may require laptops to be grounded. Then economics comes into play. It’s cheaper to make/stock one power supply chassis usable worldwide with localization coming through cheap power cords rather than creating different power supplies for each region’s requirements. The costs of complexity can be incredible.
Maybe it’s the possibility of maximizing profit: one more thing to dissuade Japanese/British from ordering electronics in America, where they’re usually cheaper. Force them to buy locally where Dell, Toshiba, etc., can make more money. Now that makes some sense, too.
I hope someone with an electrical engineering background can clear up whether this is an electrical requirement. On my 2 laptops, there are only 2 conductors in the connector at the laptop end. Could the power supply connect the earth pin to the laptop through that connector? I’m doubting it from what little I know of the use of the third pin. Traditionally it has been attached the equipment’s metal case so that if a hot wire came into contact with the case, the power would be shunted to ground before shocking someone touching the case. Without metal cases, this isn’t a possibility. Again, this is about all I know on the topic, so I’m hoping someone’ll fight my ignorance.
No chance that this is about grounding. These are fully insulated, and the choice of two or three pin connections seems to be legacy more than anything else.
Or, more likely, as part of an EMI-suppression system, as Crafter_Man suggested. Switching power supplies are very noisy as a matter of course. The ground may be necessary in order for the unit to qualify for FCC part 15 type acceptance, in the US at least.
Interesting. I’ll have to ask around to see what Japanese engineers have to say about EMI in the line. I knew laptop power supplies frequently have a choke at the laptop end, but it didn’t occur to me that the EMI would go the other way. It’s not something I think about much. With our complete lack of earth ground on our outlets, I have something to ponder and research.
So, GorillaMan, the third pin is just there to open the slots in the outlet for the other pins. Is it plastic, by any chance? I bought a radio in England and it had a plastic ground pin. Sorta taken aback the first time I saw it.
Wonder where the ground wire goes? Nowhere? :dubious:
