Which term best describes a 59 device?

The 59 device, commonly referred to as an "overvoltage relay," is specifically designed to detect electrical overvoltage conditions in a system. When voltage levels exceed predetermined thresholds, the relay activates to protect equipment from damage caused by excessive voltage. This is critical for maintaining the integrity of electrical systems, as sustained overvoltage can lead to failures or even catastrophic damage to electrical components.

In contrast, overcurrent devices monitor the current flowing through the circuit, ground fault devices are concerned with detecting faults to ground (often protecting against shock or fire hazards), and short circuit relays specifically respond to very high currents that occur during short circuit conditions. Each of these devices fulfills different protective roles in electrical systems, but for the specific case of a 59 device, the key function is to detect and respond to overvoltage conditions.