Delta LA303 surge arrestor, 4-wire AC (for 120V or 240V split-phase)
A surge arrestor helps to provide immediate, and reliable protection against any high voltage surge (such as that of a lightning strike). Your breaker is incapable of providing protection against this “lightning fast” surge of electricity. By the time your breaker has switched off, the surge has already done its damage, which is why it is important to have a surge arrestor in your system.
The LA303 is a type of silicon-oxide varistor, that conducts when the Voltage gets high enough. They provide surge protection up to 60,000 Amp at budget pricing. This arrestor is a 3-phase 4-wire industrial surge arrestor for use up to 600V AC, and it can be used with 120 Volt AC single-phase, 240V AC split-phase, or 3-phase 208V or 480V.