The nominal rating of electrical switches refers to which of the following?

The nominal rating of electrical switches specifically indicates the current rating with contacts closed. This rating is crucial because it represents the maximum current that the switch can safely carry when it is in the "on" position and the contacts are effectively conducting electricity. Understanding this rating is vital for ensuring that the switch can handle the load without overheating or failing, which is essential for both safety and operational reliability in electrical systems.

Other options relate to different characteristics of switches but do not accurately define the nominal rating. For example, the voltage rating tells you the maximum voltage at which the switch can operate safely, and the short circuit rating refers to the ability of the switch to withstand a fault condition without damage. Meanwhile, the current rating with contacts open does not reflect the operational limits when the switch is in use, as the contacts would not be passing current in that state. Therefore, current rating with contacts closed is the most relevant measure for determining the switch's nominal performance under normal operating conditions.