How are switches rated?

• A. By maximum voltage they can withstand
• B. By maximum current switch can pass when closed
• C. By number of circuits they can control
• D. By their physical size and structure

Answer: (B)

The rating of switches is primarily based on the maximum current that they can safely pass when they are closed. This current rating indicates the switch's ability to carry electrical current without overheating or failing. It is essential for ensuring safety and reliability in electrical systems, as exceeding this current rating can lead to damage to the switch and potential hazards such as electrical fires.

While the maximum voltage a switch can withstand is an important consideration, the primary function of a switch is to control current flow. Thus, the maximum current rating is the decisive factor in determining how a switch is utilized in electrical applications.

The other options relate to different aspects of switches but do not accurately represent how they are rated. For instance, while the number of circuits a switch controls and its physical size may influence its application, they are not the primary criteria for determining a switch's rating in standard practice.