Blue Sea Systems Dual PowerPost One 5/16in and One 3/8in Stud

The Blue Sea Systems Dual PowerPost mounts two independent stud terminals on one screw-down base, most commonly used to extend an outboard engine's factory wiring harness or to connect two heavy conductors at a single junction point without the footprint of a full busbar.

Key features

• One 5/16"-18 and one 3/8"-16 stud
• Designed for connecting high-amperage conductors
• Mounts with #10 (M5) screws
• Includes one black and one red insulator boot

This connector is a familiar sight in outboard engine wiring, where the factory harness sometimes needs a few extra feet to reach the battery on a boat with a longer transom or a relocated battery box. The two-stud, screw-mounted design keeps positive and negative extensions organized side by side rather than floating separately in the bilge or engine well.

Torque each stud to 120-140 in-lb (13.56-15.82 Nm). Install the red insulator over the positive stud and the black insulator over the negative stud once wiring is complete, and mount the block itself somewhere accessible for future service, since outboard harness extensions are a common point to re-inspect during routine engine maintenance.

Because both studs share one mounting base, plan the installation location with enough room for two cables to route in without crossing each other or straining the connections when the engine tilts or the boat flexes underway. Confirm the ring terminals you're using match this connector's stud size before ordering, since a loose-fitting terminal won't seat flush and can work its way toward a poor, resistive connection over time as vibration loosens it further.