Final answer:
A surge protector or surge suppressor is the protective device designed to limit voltage spikes by discharging or bypassing surge current, and there are several related devices like GFI, isolation transformers, and circuit breakers providing similar protections.
Step-by-step explanation:
The protective device for limiting voltage spikes by discharging or bypassing surge current is typically referred to as a surge protector or surge suppressor. There are several devices with similar protective functions, such as ground fault interrupters (GFIs), isolation transformers, and circuit breakers. A GFI is designed to prevent shock by detecting the loss of current to unintended paths and interrupting the flow of electricity. An isolation transformer provides a high resistance between the voltage source and the device in operation. This high resistance prevents a complete electric circuit, adding an extra layer of protection, especially where grounding is not adequate. Lastly, circuit breakers are safety devices that automatically open to protect a circuit when sustained current exceeds safe limits, which can be reset after triggering.