datasheet - Is a switches voltage and current rating a hard limit?

I have a need for a switch that can handle 28Vdc at about ~1A.

The switches I would like to use have a rating of 24Vdc at 5A.

I would think that the limit of switch is the power, so if we take a switch at 24V and 5A, then it can handle 120W. My reasoning is that a switch can run at higher or lower voltage currents, so long as its less than the 120W (in this case). A 24V 5A switch can be used for a 28V 1A application.

Is the reasoning behind that correct ? Am I absolutely limited to 24V 5A spec'd by the datasheet ?

Example switch

Answer

The answer to this is closely related to the answer to an old question about connectors.

As in the connector question, the main thing you need to remember is that the current through the switch and the voltage between the switch and ground don't tell you the power consumed by the switch. Typically they tell you the power consumed by the load.

But with switches the failure mechanisms are slightly different than in connectors. While the current rating is typically related to \$I^2R\$ heating at the contact, the over-voltage failure meachanism is typically reduced durability due to arcing across the contacts during making and breaking, rather than breakdown in the material between the terminals.