220-1102 Question 709
Single answerEquipment groundingA technician is troubleshooting a desktop PC in a small office. Users report a mild tingling sensation when touching the metal case, and the system intermittently shuts down when a laser printer on the same power strip starts printing. The PC uses a standard three-prong power cord, but the wall outlet is old and may not be wired correctly. Which action should the technician take FIRST to address the likely equipment grounding issue safely and professionally?
- A
Use a receptacle tester or multimeter to verify the outlet has proper hot, neutral, and ground wiring before reconnecting the PC
- B
Replace the PC power supply immediately because tingling on the chassis means the PSU has failed
- C
Use a three-prong-to-two-prong adapter so the PC can continue operating until the outlet can be upgraded
- D
Connect the PC case to a nearby metal water pipe with a jumper wire to create a temporary ground
Show answer and explanation
Correct answer: A
Explanation
This scenario focuses on equipment grounding, which is intended to provide a low-resistance path for fault current and help prevent exposed metal parts from becoming hazardous. A tingling chassis and problems triggered by other equipment on the same strip are warning signs that the outlet may be ungrounded, open-ground, reverse-wired, or otherwise faulty. In A+ troubleshooting, the technician should first verify the external power source using a receptacle tester or meter before replacing parts inside the computer. Best practice is to stop using the affected outlet until the wiring is checked and corrected, typically by facilities staff or a licensed electrician. This aligns with standard electrical safety guidance and common field practice: do not bypass grounding, do not create improvised grounds, and do not assume the PSU is the root cause until the power source has been validated.
- A. Correct.
Correct. The symptoms suggest a possible missing or improper equipment ground at the receptacle, which can allow leakage current to be felt on the chassis and can contribute to instability. The safest first step is to test the outlet wiring with an appropriate tester or meter and remove the system from use until the grounding issue is verified and corrected. This matches standard troubleshooting practice: verify the power source and outlet condition before replacing internal components.
- B. Incorrect.
Incorrect. A faulty power supply is one possible cause, but replacing it first skips a critical safety check. If the receptacle is improperly grounded or miswired, a new PSU would not resolve the root cause and the hazard could remain. The technician should confirm the building power and grounding are correct before swapping hardware.
- C. Incorrect.
Incorrect. Using a cheater adapter defeats the safety purpose of the grounding conductor unless it is properly bonded through a correctly grounded receptacle system, and in office support this is not an appropriate fix for a suspected grounding fault. It can leave the equipment ungrounded and increase shock risk.
- D. Incorrect.
Incorrect. Improvised grounding to plumbing is not an acceptable IT support practice and may violate electrical code and site policy. It can create additional hazards, especially if the pipe is not part of a bonded grounding system. Grounding problems should be corrected at the receptacle or branch circuit by qualified personnel.