Fiber Optic Cable Cap-Type Junction Box

Fiber optic junction boxes typically use either dome (vertical) or horizontal cap types, designed to protect splices and manage fiber routing for indoor and outdoor applications.

Cap Types

1. Dome (Vertical) Cap

• The dome or vertical type features a rounded top that seals the enclosure, providing robust protection against environmental factors such as moisture, dust, and UV exposure.
• Commonly used in outdoor aerial or underground installations, especially for FTTH "tap" points where drop cables are spliced to distribution cables.
• Offers high fiber capacity, ranging from 24 to 192 fibers, and allows for organized storage of spliced fibers with bend radius protection . 2. Horizontal Cap
• The horizontal type has a flat or slightly curved top, making it easier to mount on walls or poles in limited-space environments.
• Often preferred for indoor or compact outdoor installations due to its smaller footprint and easier access for maintenance.
• Supports fiber splicing and distribution with removable trays or cassettes for adapters like SC or LC .

Applications and Features

• Indoor Use: Wall-mounted enclosures with horizontal caps are common for residential or commercial FTTH networks, providing termination points for optical fibers and adapters. They often include splice trays, pigtails, and cable glands for neat fiber management .
• Outdoor Use: Dome-type closures are ideal for harsh environments, offering O-ring seals, heat-shrink cable sealing, and protection for feeder and distribution fibers .
• Capacity and Flexibility: Both cap types can accommodate multiple adapters and splices, with removable panels or cassettes for easy installation and maintenance. Some models support PLC splitters and multiple drop cable outputs .

Summary

Choosing the cap type depends on the installation environment and space constraints:

• Dome/vertical caps for outdoor, high-capacity, and weather-resistant applications.
• Horizontal caps for indoor or compact installations where accessibility and wall-mounting are priorities. Proper selection ensures fiber protection, organized splicing, and efficient network maintenance.