"There are two potential victims—the user, and the device," says Arthur Shi, technical writer at iFixit. "For users, the biggest danger is electrocution via wall AC current. Fortunately, chances are usually low." That's because, when AC current from the wall reaches the power brick, it gets converted to DC power before flowing to your device. Most frayed wires happen on the DC side of the cable—the one that plugs into your computer—rather than the more durable AC side, which plugs into the wall. However, Shi says, "If the AC wire is frayed, you should immediately stop using it and repair or replace it."