Sierra Marine RK40700G DPDT Rocker Switch, 20A 12V

The Sierra Marine RK40700G is a heavy-duty rocker switch built for the helm, the dash, or any switch panel on your boat. It's an On-Off-On, double pole double throw (DPDT) switch rated for 20 amps at 12 volts DC, with a green illuminated halo so you can find it and read its state in the dark. Black rectangular body, clean lines, and the kind of no-nonsense build Sierra puts into its Marine Series electrical parts.

Here's what makes a DPDT On-Off-On switch worth knowing about. It has a center Off position and two separate On positions, and it switches two circuits at the same time. That combination lets you do things a simple on/off switch can't. The most common job is reversing polarity, which is exactly how you run a reversible load forward and back from a single switch. Think trim tabs, a jack plate, a reversible blower, or a small reversing motor. Flip it one way and the load runs one direction. Flip it the other way and the polarity swaps, so the load runs the other way. Center it and everything's off. You can also use the two poles independently to control a pair of separate circuits from one lever.

That flexibility is why Sierra calls this the Multi-Purpose Switch in its Marine Series. It's the kind of part you buy once and find three uses for while you're rigging the rest of the panel.

The green illumination is the detail you'll appreciate at night. On a dark helm, an unlit switch is just a guess. This one carries a green halo so it stands out on the panel and tells you at a glance what's live. It's a dependent-illumination design, so the green light is tied to the switched circuit rather than run off its own separate feed.

About that 20 amp rating. That's a real, usable number for most accessory switching, running cabin and cockpit lights, a livewell pump, electronics, courtesy lighting, blowers, and similar loads. What we'd steer you away from is pushing a big continuous draw straight through any panel rocker. An anchor windlass, a big winch, or anything that pulls serious current is better handled by having the switch trigger a relay or solenoid, and letting that heavier device carry the load. You get the convenience of a helm switch without cooking the contacts. That's just good marine wiring practice, and it's how the folks who rig boats for a living do it. When in doubt, size for the load and switch a relay.

Installation is straightforward. It drops into a rectangular panel-mount cutout, so measure the switch body against your panel before you cut, and give yourself a little depth behind the panel for the terminals and your wiring. Use marine-grade tinned wire sized to the load, crimp on clean connectors, and fuse the circuit at the source. Boats vibrate, so a dab of thread locker or a lock washer on the terminal screws keeps everything tight over a season of pounding through chop.

Mount it where it gets a little shelter if you can. Any switch lives longer out of constant spray and direct sun, and a quick freshwater rinse of the panel after a salt day never hurts. Sierra builds this part to stand up out on the water, meeting or exceeding the original equipment it replaces, which is what you want when you're wiring something you'd rather not touch again for years.

Who's it for? Anybody rigging or re-rigging a switch panel who needs a clean, illuminated, reversible switch that won't look out of place next to the rest of the helm. First boat or fifth, if you've got a reversible accessory or a couple of circuits to manage, this is a simple, honest part that does the job. It's the switch on its own, so plan on supplying your own wire, connectors, and fuse to finish the install.