A PC power supply, has a protective function for the computer. Protection device consists of several protection circuits that have different responsibilities, and in emergencies will be shut down the computer. The first protection system is the current limit. Each branch of the pwer supply connector should have this protection and it is activated whenever there is noncompliance on the power supply output current limit. One example is a short circuit. This should be a provider of energy, so it can be compensated by a PC power supply.
To protect the computer components, surge protection is required. Protective functions of a PC power supply provides power similar to that limitation, when it reaches a certain threshold, the power supply is turned off.
Modern PC power supplies have fans and temperature sensors to protect against overheating. When you reach a certain temperature, turn off the PC power supply to protect equipment and computer components. This is especially important if the fans turned out and otherwise is the thermal destruction of components.
All devices are now equipped with no load function. No load function detecting that the connector is not used and ensure that the line was in a state of shutdown until it reconnected.