Computers are electronic equipment and therefore consume electricity. Although most components in a computer operate on low voltages—in the safe range between 3.3 and 12 volts DC—the main power source and the monitor use high voltages. This lesson sets out some basic high-voltage electrical safety guidelines.
After this lesson, you will be able to:
Estimated lesson time: 5 minutes
- Identify high-voltage hazards.
- Define some common guidelines for electrical safety.
Standard wall outlets in the U.S. provide a nominal 120 volts AC and are rated to deliver currents between 15 and 20 amps. Under certain conditions, it is possible to receive a lethal shock from much lower voltages than these. Inside a computer, and especially the monitor, voltages as high as 30,000 volts can exist—even after the power is turned off.
It is vital to follow basic electrical-safety guidelines when servicing a computer. There is no substitute for good old common sense. However, here are a few tips:
In the U.S., common AC wiring uses the following color coding:
|Live or hot||Black|
|Ground||Green or bare copper|
Color codes for AC wires and DC wires can be different. For example, the ground wires on the P8 and P9 connector for an AT-style motherboard are black.
The following point summarizes the main elements of this lesson: