Sierra UN42000 Push Button Switch, Momentary On-Off SPST, 10 Amp 12 Volt

The Sierra UN42000 is a momentary on-off SPST push button switch built for marine electrical panels and helm applications where a rugged, waterproof control is required. The switch operates on a momentary on-off circuit: press to close the circuit, release to open it, making it well suited for horns, bilge pumps, trim tabs, windshield wipers, and other accessory circuits that call for a push-and-hold control rather than a fixed toggle position.

Construction is extra heavy duty die cast metal for long-term durability in a marine environment, with silver contacts that resist corrosion and maintain reliable conductivity under repeated cycling. A rubber boot nut seals the actuator against water intrusion at the panel face, and the switch terminates in two boss screw terminals for a secure, vibration-resistant wire connection. The switch is rated 10 amps at 12 VDC, matching typical 12-volt marine accessory loads, and is designed for handlebar or panel mounting.

Specifications

• Brand: Sierra
• Manufacturer Part Number: UN42000
• Switch Type: Push Button
• Switch Operation: Momentary On-Off (SPST)
• Current Rating: 10 Amps
• Voltage Rating: 12 Volts DC
• Contact Type: Normally Open
• Contact Material: Silver
• Terminal Type: 2 Boss Screw Terminals
• Housing Material: Die Cast
• Boot Material: Rubber
• Ingress Protection Rating: IP54
• Mounting Type: Handlebar Mount
• Dimensions (L x W x H): 5.5 x 2.88 x 1.75 inches
• Weight: 0.1 pounds
• UPC: 808282368036

Frequently Asked Questions

What does momentary on-off SPST mean for the Sierra UN42000 switch? It means the UN42000 only closes the circuit while the button is held in; releasing the button returns it to the off position, and SPST indicates a single-pole, single-throw contact arrangement with one circuit being switched.

What is the amp and voltage rating of this switch? The Sierra UN42000 is rated 10 amps at 12 volts DC, sized for standard 12-volt marine accessory circuits.

Is the UN42000 waterproof enough for helm or deck mounting? Yes, it carries an IP54 ingress protection rating and uses a rubber boot nut seal at the actuator, giving it splash and dust resistance suitable for marine panels.

What are the terminals like on this switch? The UN42000 uses 2 boss screw terminals, which accept ring or spade connectors for a secure, vibration-resistant wire connection rather than quick-disconnect blades.

What is the switch housing made of? Sierra builds the UN42000 with an extra heavy duty die cast metal housing and silver contacts for durability and reliable conductivity over repeated use.

What are the dimensions and weight of the UN42000 push button switch? The switch measures 5.5 x 2.88 x 1.75 inches and weighs 0.1 pounds.

Can this switch be used for a horn or bilge pump circuit? The momentary on-off SPST action of the UN42000 makes it a good fit for push-to-activate circuits such as horns, bilge pumps, or windshield wipers where the accessory should only run while the button is pressed.

Is this a genuine Sierra part or an aftermarket equivalent? The UN42000 is a genuine Sierra push button switch, not a generic aftermarket substitute.

What mounting style does the UN42000 use? It is designed for handlebar or panel mounting, with the rubber boot nut sealing the actuator at the mounting surface.

Are the contacts on this switch silver or a base metal? The UN42000 uses silver contacts, chosen for their corrosion resistance and consistent electrical conductivity in a marine switch.