Rule-A-Matic Float Switch

Product overview

The Rule-A-Matic (model 35A, or 35FA with an in-line fuse holder) is an automatic bilge pump float switch. It switches the pump on when bilge water reaches 2 in (51 mm) and off when it falls to 3/4 in (19 mm), for 12 V and 24 V DC pumps drawing up to 14 A at 12 V or 7 A at 24 V.

Part of Pumps & Plumbing: Rule bilge pumps and float switches; Jabsco water pressure and washdown pumps and a manual marine toilet.

Key specifications

Model

Rule 35A

Brand

Rule

Models

35A; 35FA (with in-line fuse holder)

Voltage

12–24 V DC

Maximum current

14 A at 12 V; 7 A at 24 V

Switches on

At 2 in (51 mm) of water

Switches off

At 3/4 in (19 mm)

Wire

16 AWG, 28 in (712 mm) long

Mounting

Flat in the bilge, 1/4 in (6 mm) above the bottom of the pump strainer; up to 30° side to side, 5° fore and aft

Figures as published by Rule (the maker’s page), checked 7 October 2026. Say the model and voltage you need with your quote.

Downloads

• MM Techno Plast catalogue 2026PDF, 7.9 MB, after a short formDownload