Blue Sea Systems 9003EB-BSS Battery Switch - On/Off (FLM-5)

The Blue Sea Systems 9003EB-BSS (e-Series) ON/OFF Battery Switch is a heavy-duty battery disconnect built for marine/RV/vehicle DC systems where you need a simple, reliable way to isolate a battery bank for service, storage, or emergency shutoff. Its high-current switching capability and robust terminals make it a go-to choice for main battery disconnect duties.

Key Features

• Single-circuit ON/OFF: isolates one battery bank from one load group (straightforward disconnect control).
• High-current switching ratings for demanding DC systems.
• Tinned copper studs for corrosion resistance and conductivity; designed to accept common heavy battery lugs.

Specifications

• Continuous rating: 350A
• Intermittent rating: 600A (5 min)
• Cranking rating: up to 2000A (10 sec)
• Max DC voltage: 48V DC
• Terminal studs (lug size): 3/8"-16 (M10) tinned-copper studs; accepts 3/8" / M10 ring terminals
• Stud length: ~7/8" (22mm) (helps stack multiple ring lugs)
• Terminal stud torque: 140 in-lb (15.82 N·m) max
• Cable size to meet ratings: Up to 4/0 AWG (varies by listing; often shown as ~95–120 mm² equivalent)
• Cable clearance (for 4/0 AWG): ~1.10" (27.9mm)
• Mounting holes: accept 1/4" (M6) screws
• Ingress protection: IP66 (dustproof, heavy seas/water jets)