Voltage ratings and what they mean for the BOM
The 1.5SMC530C: The 477V reverse standoff voltage (VRWM) defines the maximum continuous DC or peak AC voltage the TVS can withstand without conducting — below this level it appears as a high-impedance open circuit. For a 480VAC line or a 400VDC bus, the 477V standoff provides margin; the clamping voltage must stay below the downstream component's absolute maximum rating. The single bidirectional channel means the device clamps symmetrically in both polarities — useful for AC-coupled signal lines or power rails where the transient polarity is unknown.