• Risks of plugging a computer into an ungrounded outlet versus a standard 3-prong outlet.electric outlet image by Albert Lozano from Fotolia.com
  
  Modern electrical systems are required to have grounded outlets for safety reasons, but older constructions were grandfathered into previous laws and not required to upgrade. If you purchase an older house, you may find that grounded outlets are not available, and you would be tempted to plug your computer into one of these ungrounded receptacles. However, this is recommended against, since damage to yourself and your computer could result.
  
  

Danger of Electrocution

• A short in a grounded computer would simply blow a fuse, thereby minimizing any risks. However, when a computer is plugged into an ungrounded outlet, a wire touching the computer's metal case would cause the case to be charged with a potentially dangerous or deadly amount of current, which may not trip any breakers. Should you touch such a charged case, while being grounded yourself, that electricity would flow through you. At that point, the breaker might trip, but you have already served as the ground "wire," and the damage would already be done.
  
  A surge protector might help a little, but even if the protector trips, the electricity still contained in the case has to go somewhere, which is unfortunately through you.
  
  

Radio Frequency Interference

• The computer's power supply contains a radio frequency interference (RFI) filter, which removes RFI currents and sends them to the case, under the assumption that the grounded computer will dissipate the current. When the computer is ungrounded, these RFI currents stay in the case, ready to be dissipated by anything acting as a ground, which will most likely be you.
  
  

Distortion

• Between RFI and free-floating voltages, hardware results can become distorted. Audio devices may pick up a "hum" from the voltage, and some modems refuse to work altogether in ungrounded circuits.
  
  

Increased Static Damage

• Any computer technician knows that static electricity can damage computer components, unless they are properly grounded. This is the purpose of the antistatic wristband attached to the computer's metal case or the habit of touching the case before touching other components. If the case is not grounded, this safeguard has little to no effect, which greatly increases the chances of static damage to components during servicing.