T-H Marine On-Off-On Toggle Switch | 15A 12V DC

The T-H Marine On-Off-On toggle switch is one of those small parts that quietly runs half the boat. It's a 15 amp, 12 volt DC toggle with a plain black plastic lever, built for the accessory circuits you flip on and off every trip. Lights, blowers, aerators, that kind of load. Nothing fancy. Just a switch that does its job and gets out of the way.

The part worth understanding here is the On-Off-On action. The lever sits in a center off position and throws two ways, up and down, each one making a separate circuit live. That's different from a plain on-off switch. With On-Off-On you can run two independent loads from one lever, say a pair of aerator pumps, or you can wire a single load so it's controlled from either direction. Flip it up for one circuit, center it to kill power, flip it down for the other. It's a flexible little switch once you know what you're working with.

It's rated at 15 amps on a 12 volt DC system. That covers most of the small accessory loads on a typical boat. A couple of courtesy lights, a livewell aerator, a bilge blower. Before you wire it in, add up the current draw of whatever you're switching and keep it comfortably under that 15 amp ceiling. And fuse the circuit. Always. A switch isn't a circuit protector, so put an inline fuse or a breaker sized at or below 15 amps on the feed side. That protects the wiring and the switch both.

On the water these end up everywhere. Deck and courtesy lights. Cabin lights. A livewell or baitwell aerator you cycle to keep bait lively. A bilge blower you run before you crank the engine. Anything 12 volt and under 15 amps that you want on a dedicated, manual switch rather than buried in an automatic circuit. The On-Off-On layout even lets you set up a two-pump arrangement off a single lever, which tidies up a crowded dash.

Installation is straightforward if you've wired a dash before. The switch drops into a panel or console cutout and the lever stands proud so you can find it by feel in the dark. It's non-lighted, so there's no backlight to wire in. If you want a switch you can spot at night, you'd pick an illuminated model instead, but plenty of boaters prefer a clean non-lit toggle for loads they don't need to see. Run your marine-grade wire to the terminals, crimp on properly sized connectors, and give every connection a shot of dielectric grease. Salt air finds bare copper fast. Use tinned wire if you have it, size your conductors to the load and the run length, and leave a little slack so the switch isn't pulling on its leads every time the hull flexes.

A quick word on where to mount it. The spec on this one lists it as a black plastic, non-lighted toggle and nothing more, so we'd treat it as a standard panel switch rather than a fully sealed waterproof unit. Mount it somewhere that stays out of direct spray, behind a console or under a gunwale, and it'll give you years of service. Out in the weather, add a rubber boot over the lever for peace of mind. The black finish keeps it looking at home on just about any helm.

Who's this for? Anybody replacing a tired, corroded switch that's gone mushy, or anybody rigging up a new accessory circuit and wanting a simple, dependable toggle. It's an inexpensive part, but the wrong switch in a wet spot will leave you dead in the water at the worst time. This is a sensible, honest choice for 12 volt lights, blowers, and aerators. Wire it right, fuse it, and forget about it.