Sierra RK40630B 12V 20A Blue LED Rocker Switch SPST

Sierra's RK40630B is a 12-volt, 20-amp rocker switch built for the helm. On-off action, single pole single throw, with a blue illuminated rocker so you can find it in the dark. It's the kind of switch you wire in for cabin lights, a livewell pump, a wash-down, or any accessory circuit that pulls 20 amps or less at 12 volts.

Boaters reach for a switch like this all the time. A new console build, a refit on an older boat, or just replacing a cracked rocker that finally gave up. It's a workhorse part, nothing fancy, and that's exactly the point.

SPST is about as simple as wiring gets. One circuit, on or off. Press the top and the accessory gets power. Press the bottom and it's cut. There's no middle position and no second circuit to keep track of, which makes this a clean choice when all you need is straightforward control of a single load. Sierra builds it to stand up to salt, damp, and vibration, same as the rest of their electrical line.

The blue illumination is the part you'll appreciate at night. Running back to the dock with the cabin dark, a lit rocker tells you at a glance what's on and what's off. The lamp lights up when the switch is on. Like most illuminated rockers, it needs a ground connection for the light in addition to the load wires, so plan for that extra wire when you're working behind the dash.

Size the rest of the circuit to the switch. That 20-amp rating is the ceiling, so keep your load comfortably under it and you've got headroom to spare. Match the wire gauge to the current and the length of the run, and put a fuse or a breaker on the circuit ahead of the switch. Tinned marine wire is worth the extra cost out here. For an inductive load like a pump or a blower, a lot of folks add a diode across the load to protect the contacts from arcing. And if the switch lives somewhere it'll catch spray, a rubber boot over the rocker keeps water out of the works.

Behind the dash, an illuminated rocker carries the switched load plus a feed for its lamp, so you'll be landing a few spade terminals rather than just two. Slip on heat-shrink connectors, label each lead as you go, and you'll thank yourself the next time you're troubleshooting by flashlight in a rolling anchorage.

This is a general-purpose accessory switch. It's happy running lights, small pumps, electronics power, and similar 12-volt loads. What it isn't is a heavy-surge switch for big motors or anything drawing more than 20 amps. If your accessory pulls more than that, don't push the switch past its rating. Wire in a relay and let this rocker trigger it instead of carrying the full current itself. Your switch lasts longer and your wiring stays cooler.

Sierra's been supplying OEM engine builders and boat manufacturers for years, and their electrical parts are engineered to meet or exceed the original equipment they replace. So whether you're rewiring a tired panel or building a new one from scratch, this is a switch you can trust to keep doing its job season after season.

If you ever need to feed two circuits or want a center-off position, Sierra makes this same rocker in an on-off-on layout. This RK40630B is the straight on-off version, single pole single throw, which is what most accessory circuits actually call for. Keep it simple where you can.

Installation is straightforward. The rectangular rocker drops into a standard rectangular panel opening. If you're swapping out an old switch, measure your existing cutout and dry-fit before you commit so you're not surprised at the dash. The black housing keeps a low profile next to your other controls. Out in the salt, wipe the face down now and then, keep the connections clean and tight behind the panel, and this little switch will outlast plenty of the gear it controls.