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Notebook “Tingle” Sensation: What's Going On?

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Several weeks ago, a user from notebookforums.com reported concern about voltage. That post prompted other stories from folks like Engadget and Slashdot. About a week later, Mike, who’s one of our Customer Advocate team members, responded in the thread confirming that there’s no safety hazard with the reported tingling that some notebook users are commenting on. In a follow-up, he posted another update that confirmed that the issue does not harm internal components of a notebook.
 
Before I get further into the details of this long post, wanted  you to know that we’ve heard you and we’re taking steps.  Going forward, as we introduce new notebook models, 3-prong power adapters will be available. As noted below however, there are reasons why the 2-prong adapter is the current industry standard. 
 
3-Prong Power Adapter Survey
For existing customers, we’re currently investigating creating a program to make 3-prong power adapters available for purchase at a discounted price. We need your help, and that’s why we’re asking customers who are interested in acquiring a 3-prong power adapter to provide additional feedback via this survey on Dell.com. The survey will run from now until Monday, May 7.
 
Update 5/8: Thanks to all of you who completed the survey. Unfortunately, in the survey, we neglected to obtain contact information from you. If you completed the survey and are interested in receiving a 3-prong power adapter for a discounted price, please submit a comment to this thread and include your e-mail address. I will not publish your comment. Instead, we will e-mail you details on how to order your discounted 3-prong power adapter. We apologize for the inconvenience.
 
Because we have been shipping 2-prong adapters with the majority of our systems on a global basis for over a year now, we don’t have a ready supply of extra 3-prong adapters available. We must work with a vendor to develop a production cycle and ramp up supply.
 
Frankly, right now we are trying to estimate global demand, which will directly impact our ability to deliver a solution in a timely manner. Your feedback will help us get a better idea of how many customers would be interested.
 
“Tingle” Sensation Explained
For those of you who really want a better understanding of what the reported “tingle” sensation is, we have worked with our electrical engineers and safety teams to share a detailed description of what exactly is going on.
 
Here are some things that about the “tingle” sensation that Mike posted earlier that I think bear repeating:
  • It is not harmful to you the user.
  • It is not harmful to any of the system’s internal components.
  • This issue is not specific to Dell.
  • This issue is not specific to notebook computers even. A “tingle” sensation may be felt on many electronic devices that use a 2-prong AC power source under specific environmental conditions.



So, what’s this “tingle” sensation and what causes it? The “tingle” sensation is the transfer of energy from you, a 2-wire AC adapter/ system ground and contact with an earth ground. A “tingle” sensation may be felt when touching the exposed metal portions of the notebook and/or 2 -prong AC adapter when the AC adapter is plugged in. The “tingle” sensation is not an indication of a failed or defective ground.

 
To generate the “tingle” sensation, you must be earth grounded at the same time you are touching an exposed metal piece of the notebook while the notebook is plugged into the 2-prong AC adapter. The voltage will always be there when the notebook is plugged into the 2-prong adapter, but it is harmless to you as a user and the notebook itself. In fact, in the vast majority of cases, the voltage is not noticeable to you at all. Certain environmental elements can increase the chances of experiencing the "tingle sensation" such as weather and humidity or a person's skin condition (oily, dry, etc.) There's a bit more on this at the Dell Sweden support site.

The source of the “tingle” sensation is not your notebook, it's the 2-prong adapter. This “tingle” sensation is not caused by any defect in Dell's 2-prong adapters—they work as they are designed. Other notebook manufacturers ship with 2-prong adapters as well, and users of those notebooks may experience a “tingle” sensation if conditions are right. 2-prong adapters are becoming more common these days because they smaller, lighter and more convenient to carry—all things which are important to many notebook customers.
 
A 3-prong adapter is one option to eliminate the “tingle” sensation. The other is to change some of the environmental factors involved. As an example, the “tingle” sensation won’t happen when running the notebook on battery power. Also, you can eliminate the “tingle” sensation by connecting a grounded peripheral such as a USB printer or other device that uses a 3-prong adapter to the notebook.
 
So, how can you be sure that this issue does not cause damage to internal components? The current/voltage which results in some users feeling a “tingle” sensation does not damage the notebook because the energy flow is via the earth ground path to the chassis/AC adapter ground path. The energy does not flow through the components—they are simply not in the transmission path.
 
Several regulatory and safety agencies are in place to create and maintain standards for electronic devices. Dell meets or surpasses all applicable standards with all of our notebook and desktop systems. The logos of the applicable regulatory and safety agencies for the Dell notebook power adapters can be found on the AC adapter power brick and include the FCC, UL, CCC S&E, CSA, CE, IDA, IRAM, GS, NOM and a few others. The most important one to note will be a picture of a square within a square which indicates double insulation (2 prongs). Double-insulated refers to a safety method to protect users without an earth ground. This is done by using non conductive outer layer(s) with tight limits on current flow to earth ground. Delivering safe electronics has been a priority since Dell’s inception and we are committed to meet—and exceed—all regulatory safety requirements with our products. 
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