Toggle Switches

SPST (single-pole, single-throw) simply opens or closes one circuit — a basic on/off switch. SPDT (single-pole, double-throw) connects one common terminal to either of two output terminals, useful for selecting between two circuits. DPDT (double-pole, double-throw) operates two separate circuits simultaneously with two positions each from a single lever, commonly used to reverse motor direction or gang-switch two circuits together.

AC current naturally crosses zero volts twice per cycle, which helps extinguish the arc that forms as switch contacts separate. DC current doesn't cross zero, so the arc at a DC contact gap is harder to extinguish and causes more contact erosion — as a result, the same switch is typically rated for a lower current at a given DC voltage than at the same AC voltage. Always use the DC rating when switching a DC circuit, never the AC rating.

These describe the switch's positions and actuation type. On-off-on is a maintained 3-position switch that stays wherever the lever is set. Parentheses around a position, like (on)-off-(on), indicate a momentary, spring-return position — the switch only stays in that position while held, returning to center (off) when released. This distinction matters for control circuits needing a self-centering jog function.

Yes — standard toggle switches are not sealed against moisture and will corrode or fail if exposed to rain, spray, or washdown. For marine, outdoor, or wet-location panels, specify a switch with an IP-rated waterproof boot or sealed housing, confirming the ingress protection rating matches the actual exposure the switch will see.

Standard toggle switches commonly use a 1/4 inch (6.35mm), 15/32 inch (11.9mm), or 12mm bushing mounting hole, secured by a threaded bushing and nut through the panel. Always check the exact bushing diameter on the switch's datasheet against your panel's cutout before ordering, since these sizes are not universally interchangeable across manufacturers.