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gzeigerman
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Registered: ‎01-18-2010
Location: Gainesville, FL
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Message 1 of 9

Power Adapter Question

I just received my new thinkpad t500. For some reason, the power adapter that came with it only has a 2-prong plug, and not 3, so it is not grounding. Is this normal? Can I request they send me a grounding one?

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Message 2 of 9

Re: Power Adapter Question

Hi gzeigerman, and welcome to the Lenovo User Community!

 

Yes that's normal. All my ThinkPads, bought in the US, have 2-pin adapters.

 

There ARE 3-pin AC adapters and power cords listed in the T500 Hardware Maintenance Manual:

 

http://www-307.ibm.com/pc/support/site.wss/document.do?lndocid=MIGR-70068

 

If you really wanted 3-pin, they are sold by IBM parts.

 

 

I don't work for Lenovo. I'm a crazy volunteer!
Retired Guru
Posts: 993
Registered: ‎03-10-2009
Location: Michigan
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Message 3 of 9

Re: Power Adapter Question

Hi gzeigerman,

 

Welcome to the Lenovo forum! Smiley Happy

 

It is normal to receive the 2-prong AC adapter with ThinkPads sold in North America, and 3-prong in the rest of the world. While you could try requesting a 3-prong adapter, I'm not sure it would be either free or advantageous.

 

The T500 Hardware Maintenance Manual (section Parts List: AC adapters) has part numbers of the various adapters and line cords available for different parts of the world. Here is a good discussion of the different adapters; both the 2- and 3-pin adapters can be used worldwide, given the proper line cords. (See also this thread.) I think the 3-pin is slightly more "correct" for worldwide use because it complies with more local electrical codes. But the 2-pin should be reasonably safe; it is double-insulated. This thread confirms that the 2-pin adapters are double-insulated, use lighter and less bulky cords, and work internationally.

 

A user in this thread claims that the switching-mode power supplies inside both the 2-pin and 3-pin models totally isolate the 20VDC output (to ThinkPad) from the primary input voltage, and that there is therefore no safety difference at all between the two types. Notwithstanding that, users of some other laptops (Sony, Dell) with 2-pin adapters have experienced mild electric shocks and/or tingling when using 2-pin adapters, and cured the problem by switching to 3-pin adapters. At least in the case of the Dell XPS M1530, the problem appears to have been caused/exacerbated by the laptop's brushed-aluminum (electrically conductive) casing.

 

Bottom line is that it is normal for your North American ThinkPad to come with the 2-pin adapter, which is lighter and less bulky, and works just fine for most users. I'd recommend just using it and forgetting about it, unless you discover that you have a particular problem with it, or have some other special need for the 3-pin adapter. (In which case, can you please share with us what it is?)

 

Best regards,

Frank

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020543m
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Message 4 of 9

Re: Power Adapter Question

I'm in Canada and I also received a two-pronged plug.  My problem is that sometimes when I touch my laptop, it will reboot.  When this happens, I sometimes feel a little shock, sometimes not.  It's winter here, so the cold, dry air probably doesn't help with such electrostatic dischare problems.

 


Would a three-pronged plug, with it's grounding protect me from these reboots?

 

 

Thanks,

 

Joseph

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Message 5 of 9

Re: Power Adapter Question


@020543m wrote:

 

Would a three-pronged plug, with it's grounding protect me from these reboots?

 

The problem you're experiencing most likely relates to electrostatic discharge, not to a wiring fault with the adapter.

 

You can avoid any rebooting problems by touching something that's grounded before you touch your ThinkPad. If you don't want to feel the tingling of shock hold a piece of metal, e.g. a coin or key, and use it to make contact with ground. (Or increase the humidity in the room where you use your ThinkPad.)

 

 

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020543m
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Message 6 of 9

Re: Power Adapter Question

You're saying a problem with ESD won't be resolved with grounded cable?

 

This is a laptop so I'm using it in places like airports, so controlling the humidity is difficulut.  I have been trying to touch something grounded before, but I sometimes forget and it's inconvenient.  A grounded cable would be a much easier solution, but you seem to be saying it won't help.

 

 

Thanks for the reply,

 

 

Joseph

 

 

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Message 7 of 9

Re: Power Adapter Question


@020543m wrote:

You're saying a problem with ESD won't be resolved with grounded cable?

 


I don't see how. See fmyhr's post just above yours for a more detailed explanation.

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Message 8 of 9

Re: Power Adapter Question


@020543m wrote:

You're saying a problem with ESD won't be resolved with grounded cable?

 


A grounded mains power cable will only "ground" the power supply adapter.  The power adapter is, by necessity, double insulated - so there is no "ground" extended to the laptop. 

 

Therefore a grounded cable is not going to assist you with any isses related to electrostatic effects occurring when touching the laptop.

 

Cheers,

 

Bill

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I don't work for Lenovo
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Message 9 of 9

Re: Power Adapter Question


@fmyhr wrote:

 

Bottom line is that it is normal for your North American ThinkPad to come with the 2-pin adapter, which is lighter and less bulky, and works just fine for most users..


 

I have both 2 and 3 pin power lenovo adapters of identical rating.....  there is no difference in size and a trivially small difference (a gram or two) in the weight.

 

Cheers,

 

Bill

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I don't work for Lenovo

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