8’ grounded IEC power cable, 18 AWG

The IEC cable is also known as the C13 and C14 connector, is commonly used to provide power to computers, monitors and other peripheral devices.

Most desktop personal computers use the ten-amp panel-mounting IEC or also known as  the C14 inlet to attach the mains cord to the power supply, as do many monitors, printers and other peripherals. Many older computers also provide a panel-mounting C13 outlet for powering the monitor. In AT form factor computers this outlet was controlled by the physical power switch. With the arrival of ATX the outlet was usually permanently powered, if present on the chassis.

A three-conductor cord with a suitable power plug for the locality in which the appliance is used on one end and a C13 line socket on the other is commonly called an "IEC cord." IEC cords are used to power many other pieces of electronic equipment other than computers, for example instrument amplifiers and professional audio equipment.

If you look on the back of your computer, you will most likely see one of these cables providing power.  You can NEVER have too many of these as you will find that you are typically one short of how many you really need.