Rule 40A Rule-A-Matic Plus Automatic Bilge Pump Float Switch, 12/24/32V DC

The Rule-A-Matic Plus Automatic Bilge Pump Float Switch (part number 40A) is an automatic on/off control switch for boat bilge pumps. It activates the connected pump when water in the bilge rises to 2 inches and shuts the pump off once the water level falls back to 3/4 inch, giving hands-free, reliable bilge management without constant monitoring.

The switch is built around a strong, fully integrated, impact-resistant cover that shields the internal float mechanism from debris and helps prevent jamming, a common failure point in bilge compartments where bits of hose, sediment, and other loose material collect. It is mercury-free and includes a built-in test feature so the switch can be checked for proper operation without waiting for water to reach the trigger level. A protective shield is included with the unit. The float switch is fitted with 14 AWG marine-grade, highly abrasion-resistant blocked wire measuring 28 inches, and its exclusive moisture-tight seals are designed to keep the internal components protected in a wet bilge environment.

A detachable mounting base allows the switch to be removed for cleaning or servicing without disturbing the wiring connections. Rule recommends installing the Rule-A-Matic Plus on a flat surface within the bilge compartment for maximum performance. The switch is rated for 12, 24, or 32 volt DC systems and is backed by a 2 year warranty.

Specifications

• Brand: Rule
• Manufacturer Part Number: 40A
• Type: Float Switch
• Voltage: 12/24/32 VDC
• Amp Draw: 20 amp at 12V, 10 amp at 24V, 6.5 amp at 32V
• Activation Water Level: 2 inches
• Deactivation Water Level: 3/4 inch
• Dimensions: 4-7/8 inches L x 2-1/2 inches W x 2-3/4 inches H
• Wire Size: 14 AWG
• Wire Length: 28 inches
• Weight: 1.01 pounds
• Material: Stainless Steel
• Color: White
• Warranty: 2 years
• UPC: 042237095633

Frequently Asked Questions

What does the Rule 40A Rule-A-Matic Plus float switch do? It automatically turns a connected bilge pump on and off based on water level, activating the pump when water reaches 2 inches and switching it off once the level drops to 3/4 inch.

At what water levels does the Rule-A-Matic Plus 40A activate and deactivate? The 40A switch turns the pump on at a 2 inch water level and turns it off once the water recedes to 3/4 inch.

Is the Rule 40A float switch mercury-free? Yes, the Rule-A-Matic Plus 40A is a mercury-free float switch.

Can the Rule-A-Matic Plus 40A be tested without waiting for the bilge to fill? Yes, the 40A includes a built-in test feature that lets you check switch operation without needing water to reach the 2 inch activation level.

What voltage systems is the Rule 40A compatible with? The Rule-A-Matic Plus 40A is rated for 12, 24, or 32 volt DC systems, drawing 20 amps at 12V, 10 amps at 24V, and 6.5 amps at 32V.

What are the dimensions and wiring of the Rule 40A float switch? The 40A measures 4-7/8 inches long by 2-1/2 inches wide by 2-3/4 inches high and comes with 28 inches of 14 AWG marine-grade blocked wire.

How much does the Rule-A-Matic Plus 40A weigh? The Rule 40A float switch weighs 1.01 pounds.

Is the mounting base on the 40A removable for cleaning? Yes, the Rule-A-Matic Plus 40A has a detachable mounting base that makes it easy to remove the switch for cleaning or servicing.

How is the Rule 40A protected against jamming from bilge debris? A strong, fully integrated, impact-resistant cover shields the float mechanism of the 40A from debris and helps prevent jamming.

Does the Rule-A-Matic Plus 40A come with a warranty? Yes, the Rule 40A Rule-A-Matic Plus float switch includes a 2 year warranty.

Where should the Rule 40A float switch be installed? Rule recommends mounting the Rule-A-Matic Plus 40A on a flat surface in the bilge compartment for maximum performance.

How does the Rule-A-Matic Plus 40A compare to the Rule Super Switch 37A? Both the 40A and the Super Switch 37A activate at 2 inches and deactivate at 3/4 inch and are mercury-free, but the 40A adds a built-in test feature, an impact-resistant cover, and an included shield, while the 37A offers a larger float for increased buoyancy and a 5 year warranty compared to the 40A's 2 year warranty.