Blue Sea Systems 4321 Circuit Breaker Switch Panel, 4 Position with 12V Socket and Dual USB Charger, Gray

The Blue Sea Systems 4321 is a water-resistant circuit breaker switch panel built for boats that need reliable, protected circuit switching in a single retrofit-friendly footprint. The panel provides 4 illuminated 15A circuit breaker positions, each giving switching, ON indication, and overcurrent protection in one control, plus a built-in 12/24V 2.1A DC USB charger for powering phones and electronics at the helm. Wiring is simple: a two-wire connection powers the entire panel, with terminals sized for #10 ring terminals that screw directly to the bus bars for a secure, corrosion-resistant connection. Each of the 4 breaker positions uses a 1/4 inch male quick-connect terminal rated for 12V DC at up to 45A maximum operating amperage, with a ring terminal size of M5 (#10) at the bus bar. The panel surface is built from UV-stabilized, flame-retardant polycarbonate/ABS that resists corrosion, while silicone breaker boots and a gasket seal out water; mounted with the gasket in place, the panel front carries an IP66 rating, standing up to powerful water jets. A set of 15 square format circuit labels is included and can be swapped out easily, with additional standard or custom labels available separately. The panel mounts with stainless steel #6 x 5/8 inch screws and uses industry-standard sizing, so it drops into existing panel cutouts for straightforward retrofits. Includes the panel, 15 common labels, mounting screws, and instructions.

Specifications

• Brand: Blue Sea Systems
• Manufacturer Part Number: 4321
• Nominal Voltage: 12V DC
• Maximum Operating Amperage: 45 Amps
• Number of Positions: 4
• Terminal Type: 1/4 inch Male Quick Connect
• Ring Terminal Size: M5 (#10)
• Wire Connection: Two-wire connection, requires #10 ring terminals
• Mounting Hardware: Stainless Steel #6 x 5/8 inch mounting screws
• Included Accessory: 12/24V 2.1A DC USB Charger
• Circuit Labels: Set of 15 square format labels included
• Material: Polycarbonate/ABS
• Color: Gray
• Ingress Protection Rating: IP66 when mounted with gasket in place
• Item Dimensions: 8.5 x 5.5 x 4 inches
• Weight: 1.15 pounds
• UPC: 632085043216
• Warranty: Lifetime

Frequently Asked Questions

How many circuit breaker positions does the Blue Sea Systems 4321 have? The Blue Sea Systems 4321 has 4 circuit breaker positions, each an illuminated 15A breaker that provides switching, ON indication, and overcurrent protection.

Does the 4321 panel include a USB charger? Yes, the 4321 includes a built-in 12/24V 2.1A DC USB charger for powering phones and other devices.

What is the maximum amperage rating of this panel? The panel is rated for a maximum operating amperage of 45 Amps at 12V DC.

Is the Blue Sea Systems 4321 waterproof? It is water-resistant rather than fully waterproof: silicone breaker boots and a gasket seal the panel, and when mounted with the gasket in place the panel front carries an IP66 rating, protecting against powerful water jets.

What size ring terminals does the 4321 use for wiring? The 4321 uses a two-wire connection and requires #10 ring terminals, which screw to the bus bars for a secure connection; the ring terminal size at the bus bar is M5 (#10).

What are the dimensions of the panel? The Blue Sea Systems 4321 measures 8.5 x 5.5 x 4 inches.

What material is the panel surface made of? The panel surface is polycarbonate/ABS that is UV-stabilized and flame retardant, and will not corrode.

What mounting hardware comes with the 4321? Stainless steel #6 x 5/8 inch mounting screws are included with the 4321 panel.

How many circuit labels are included, and can they be replaced? A set of 15 square format circuit labels is included with the 4321, and they are easy to replace; additional standard or custom labels are available separately.

What is included in the box with the 4321? The package includes the panel, 15 common square circuit labels, stainless steel #6 x 5/8 inch mounting screws, and instructions.

Will the 4321 fit an existing panel cutout on my boat? Yes, the Blue Sea Systems 4321 uses industry-standard panel sizing and mounting, allowing it to be retrofitted into an existing panel cutout.

What color is the 4321 switch panel? The Blue Sea Systems 4321 switch panel has a gray finish.