Overview

The Attwood Marine 4202-7 is an automatic float switch for 12V and 24V DC bilge pump systems. It switches the pump on when water reaches about 2 inches and supports pump loads up to 12 amps at 12V DC or 6 amps at 24V DC, which makes it a straightforward fit for many small to mid-size bilge setups that still use a separate pump and switch.

Its housing sits low in the bilge and can be mounted on a surface from level up to 24 degrees, which helps when space is tight or the pump area is not perfectly flat. The switch also uses an integral cover to calm bilge slosh and help keep debris away from the float, so the pump is less likely to cycle when the boat rocks at the dock or underway.

This is a practical option for owners replacing a worn float switch or converting a manual bilge pump to automatic operation without changing the rest of the system. The 36-inch wire leads give enough length for clean routing in many bilge compartments, and the unit is CE-rated and mercury-free.

Key features

• Works with 12V and 24V DC bilge pump systems
• Handles pump loads up to 12 amps at 12V DC or 6 amps at 24V DC
• Activates the pump at about a 2-inch water level
• Mounts from a horizontal surface up to a 24-degree angle
• Integral cover helps reduce nuisance cycling from bilge slosh and helps keep debris away from the float
• Mechanical switch with a sealed mechanism that helps resist moisture, fume ignition, and electrical shock
• Includes 36-inch wire leads for wiring into the pump circuit
• CE-rated and mercury-free

Compatibility and fit

This switch is meant for DC bilge systems and should be matched with a pump that stays within its current limits. It is wired in series with the positive side of the pump circuit, so it suits common 12V and 24V boat electrical systems where a separate float switch controls a non-automatic bilge pump.

It can be mounted as a stand-alone switch close to the pump, and it also fits Attwood V-Series pump brackets used on models 4204, 4206, 4207, 4209, and 4212. That can simplify replacement work on boats already using that pump family.

Installation and setup

The switch should be mounted at least level with the pump mounting surface and as close to the pump as practical. In a bilge that sees vibration, standing water, and dirt, keeping the float path clear matters as much as the wiring. The cover helps, but the float still needs room to move freely without hoses or harnesses touching it.

Wire connections should be waterproof and kept above the highest likely waterline in the bilge. This switch is for DC use only and should not be connected to AC systems or AC-to-DC converted power sources. Fuse protection should follow the pump manufacturer's rating for the pump in the circuit.

Use on board

This float switch makes sense on fishing boats, runabouts, center consoles, trailer boats, and cruising sailboats that use a separate bilge pump and want automatic operation without moving to an all-in-one automatic pump. It is especially useful where the bilge area is shallow and the switch needs to sit low without taking much room.

For owners who prefer simple mechanical switching over electronic water sensors, this unit keeps the setup easy to understand and easy to service. Regular checks for debris and occasional manual testing are usually all that is needed to keep it working as intended.