Electroswitch 78PB04D

Current rating is the maximum current that a fuse will carry for an indefinite period without too much deterioration of the fuse element.

The current rating of a contact is defined as the current level that creates a certain temperature rise of the contact spring — usually 20°C or 30°C. Both electrical and thermal factors govern the heat created by the current.

The maximum switching voltage of a relay is the maximum voltage that can be across the contacts whether the relay is open or closed. Operating a relay with high voltages present can cause arcing, and this in turn erodes the contacts and eventually degrades contact performance.

A current coil is basically a coil, such as, a wire wrapped around an electrical conductor.