A junction box is a protective enclosure where electrical wires meet and are joined. It helps organize connections and keeps them out of harm’s way.

• Protects splices: Covers wire connections from dust, moisture, and accidental contact.
• Supports safety: Using an approved box with a cover can help meet local code requirements.
• Makes maintenance easier: Provides a clear, accessible spot to inspect or add connections later.
• Adapts to environments: Outdoor models often carry IP or NEMA ratings for weather resistance.

On product pages, look for material (plastic or metal), size, and ratings like IP65–IP67 or NEMA 4X to match your indoor or outdoor needs. If you’re unsure, consider checking with a licensed electrician.

They’re related but used a bit differently.

• Junction box: A general enclosure for splicing, branching, or terminating wires. It may have knockouts and a cover, and comes in plastic or metal options for indoor or outdoor use.
• Conduit box: Designed to connect lengths of conduit and route conductors. It usually features threaded entries or hubs to accept conduit fittings, aiding direction changes and transitions.
• Shape and ports: Conduit boxes often have specific port configurations; junction boxes come in various shapes and sizes for wire splices.
• Ratings: Both can be weatherproof; check IP/NEMA markings and entry types to match your system.

Choose based on whether you’re primarily splicing wires or building a conduit run.

They serve different jobs in a wiring setup.

• Outlet box: Made to mount a device—like a switch, receptacle, or fixture. Sizes are often described as 1-gang or 2-gang, and device openings face outward for a cover plate.
• Junction box: Meant for wire splices and branching without a device attached. It’s typically closed with a solid cover.
• Capacity and layout: Outlet boxes provide mounting points for devices; junction boxes prioritize space for wire connections.
• Indoor/outdoor options: Weatherproof outlet boxes with threaded outlets exist for exterior fixtures; junction boxes also come rated for outdoor environments.

Check dimensions, cubic inch capacity, and ratings to match your application.

You’ll typically use a junction box anytime wires are spliced outside of a device or fixture.

• Adding or extending circuits: When joining cables to reach a new location.
• Outdoor connections: For landscape lighting, cameras, or other exterior equipment—use weather-rated enclosures.
• Transitions: When switching from underground cable to above-ground wiring or conduit.
• Accessibility: Boxes provide a defined, covered spot for inspection later.

Local electrical codes often require splices to be inside approved boxes with covers. Look for boxes with appropriate IP/NEMA ratings and entry options (knockouts or threaded hubs). If you’re unsure about code requirements, consider consulting a licensed electrician.

Sizing depends on what’s going inside and how many conductors you’re joining.

• Conductor count and gauge: More or larger wires require more volume. Product pages often list cubic inch capacity or internal dimensions.
• Devices or connectors: Allow space for terminal blocks, wire nuts, or cable glands so nothing is cramped.
• Bend radius and clearance: Leave room for comfortable wire bends and future access.
• Environment: For outdoor use, consider IP65–IP67 or NEMA weather ratings; size up if you’re adding cord grips or seals.

When in doubt, opting for a slightly larger enclosure can make installation and later maintenance easier. Always verify local box-fill rules before purchasing.