Blue Sea E Series Single Circuit Battery Switch

The Blue Sea Systems E-Series 9003E and 9004E Battery Switch is a heavy-duty marine battery isolation switch designed for inboard petrol and diesel engines. Rated at 350A continuous, it delivers dependable battery isolation for demanding marine electrical systems while remaining ignition protected for safe installation aboard petrol-powered vessels.

Constructed with tin-plated copper 3/8" (M10) studs, the switch provides maximum conductivity and excellent corrosion resistance. The extended 7/8" (22mm) terminal studs allow multiple cable terminals to be fitted, while the one-piece stud design ensures long-term reliability without loosening.

The 9004E is equipped with a Alternator Field Disconnect (AFD) providing additional protection for your charging system by safeguarding the alternator's diodes if the battery switch is accidentally turned to the OFF position while the engine is running. Where alternator protection is not required, the AFD terminals can instead be used to connect an LED indicator, allowing the LED to illuminate whenever the battery switch is in any position other than OFF. This provides both increased installation flexibility and a convenient visual indication that the battery system is active.

The reinforced polycarbonate housing supports both surface and rear panel mounting, and the tactile knob design enables switch position identification by touch. Compatible with Perko and Guest low-amperage battery switch mounting patterns, the E-Series also meets American Boat and Yacht Council (ABYC) battery switch requirements.

• 350A continuous rating for inboard petrol and diesel engines
• 45% higher continuous rating than standard battery switches
• Ignition protected for installation aboard petrol-powered boats
• Tin-plated copper terminal studs for superior conductivity and corrosion resistance
• Accepts 3/8" (M10) ring terminals
• 7/8" (22mm) terminal studs accept multiple cable terminals
• One-piece terminal stud construction prevents loosening
• Surface or rear panel mounting options
• Tactile knob position indicator
• International legend label
• Accepts up to 4/0 AWG (95mm²) battery cable
• Fits Perko and Guest low-amperage battery switch hole patterns
• Reinforced polycarbonate case
• CE marked
• Meets ABYC battery switch requirements