How to Check for Disconnected Computer Power Cable Connections

Check the cabling if your computer won't turn on

What to Know

  • Make sure power cable fits firmly in the three-pronged power-supply port on the rear of the computer case.
  • Verify other end of power cable is securely plugged in to wall outlet, surge protector, power strip, or battery backup.
  • If applicable, verify that surge protector, power strip, or battery backup is securely plugged into the wall outlet.

This article explains how to check your computer for loose or improperly connected power cables. This could be the culprit if your computer doesn't turn on or shuts off abruptly.

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Check the Power Cable Behind the Computer Case

Picture of a computer power cable connection
Power Cable Connection Behind Computer Case. © Tim Fisher

Power cables often wiggle loose from PC cases over time, or sometimes after being moved around. Checking every point where electricity is delivered to the computer system is usually a first step when a computer isn't receiving power.

The first place to start is with the power cable that connects at the rear of the computer case. The power cable should fit firmly in the three-pronged port on the power supply.

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Verify PC Power Cable Is Securely Plugged In

Picture of power cables plugged in to a power strip
Power Cable Connections on Power Strip. © Tim Fisher

Follow the power cable from the back of the computer case to the wall outlet, surge protector, or power strip that it is (or should be) plugged in to. If your PC is attached to a battery backup unit, follow the cable there.

Make sure the cable is securely plugged in.

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Verify Power Strip or Surge Protector Is Securely Plugged in a Wall Outlet

Picture of a power cable plugged in to a wall outlet
Power Cable Connection on Wall Outlet. © Tim Fisher

If the power cable from the PC case was plugged into the wall outlet in the last step, your verification is already complete.

If your power cable is plugged into a surge protector or a power strip, ensure that it's securely plugged into the wall outlet. The same is true for battery backup: make sure the backup unit is firmly plugged in to its power source (likely the wall).

If everything is plugged in to the computer, check for disconnected monitor power cable connections. Your computer might turn on fine, but it could appear to be off if the monitor is blank.

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