EZ Solar JB-3 Rooftop PV Junction Box, Rail Mount
A Cleaner Way to Manage Rooftop PV Connections The EZ Solar JB-3 is a rail-mounted rooftop junction box designed to provide a protected location for PV wire transitions, splices, terminal blocks and other exterior electrical connections. Flexible stainless-steel clamps allow the enclosure to mount directly to rounded or squared racking profiles, including Kinetic Solar racking rails and Unistrut-style channel. Its self-leveling design keeps installation straightforward while the UV-resistant polycarbonate enclosure provides long-term outdoor durability. Why You'll Love It Compatible with Kinetic Solar racking rails Mounts to standard Unistrut-style channel Fits many rounded or squared solar racking profiles No additional roof penetration required for mounting Self-leveling stainless-steel rail clamps Type 3R rainproof enclosure for outdoor installations UV-resistant polycarbonate construction Includes a DIN rail and five-port grounding bar Suitable for PV systems up to 1,000V and 80A UL 1741 and CSA C22.2 No. 290 compliant Made in the USA Versatile Rail & Channel Mounting The included stainless-steel clamps allow the JB-3 to attach directly to many common solar racking rails and structural mounting channels. This includes Kinetic Solar racking products, Unistrut-style channel, and other compatible rounded or squared rail profiles. The enclosure self-levels as the clamps are tightened, making it easy to position beside a solar array or wherever exterior PV wiring needs to be joined, transitioned or routed into conduit. Because the enclosure mounts directly to the racking or channel, it does not require a separate roof penetration for mounting. A properly flashed penetration may still be required wherever wiring or conduit enters the building. What's Included JB-3 polycarbonate enclosure body Removable enclosure lid DIN rail Five-port grounding bar Two stainless-steel rail-mount clamps Lid and mounting hardware Fittings and Electrical Connectors Sold Separately Conduit fittings, cable glands, strain-relief fittings, wire connectors and terminal blocks must be selected for the specific installation. Use appropriately rated outdoor fittings and electrical components that maintain the enclosure's Type 3R rating. The nonconductive enclosure does not automatically provide bonding between metal conduit fittings. Any required bonding jumpers or other bonding provisions must be installed separately. Specifications Manufacturer EZ Solar Model JB-3 Mounting Compatibility Kinetic Solar rails, Unistrut-style channel, and compatible rounded or squared racking profiles Maximum System Voltage 1,000V Maximum Current 80A Allowable Conductor Range 14–6 AWG copper Minimum Conductor Temperature Rating 75°C Enclosure Rating Type 3R Enclosure Material UV-resistant polycarbonate Maximum Sidewall Fitting Size 1 inch Maximum Floor Pass-Through Size 1 inch Roof-Slope Range 2.5:12 to 12:12 Ambient Operating Temperature −35°C to +75°C Compliance UL 1741 and CSA C22.2 No. 290 Certification Intertek, File 5025824 Country of Manufacture USA Frequently Asked Questions What is this junction box used for? The JB-3 provides a protected outdoor enclosure for rooftop PV wiring connections. It may be used for transitions between PV wire and conduit wiring, cable splices, terminal blocks and other approved electrical connections. Will it mount to Kinetic Solar racking? Yes. The flexible stainless-steel clamps allow the JB-3 to mount directly to compatible Kinetic Solar racking rails. The self-leveling design makes it easy to position the enclosure beside the solar array. Shop Solar Racking Will it mount to Unistrut-style channel? Yes. The stainless-steel clamps can secure the JB-3 to standard Unistrut-style structural channel, making it useful for ground-mounted arrays, equipment racks, pole-mounted systems and other custom solar structures. Does installation require another roof penetration? The enclosure mounts to the solar racking or structural channel and does not require a separate mounting penetration through the roof. A properly flashed wire or conduit penetration may still be required wherever the electrical wiring enters the building. Are cable glands and conduit fittings included? No. Cable glands, conduit hubs, strain-relief fittings and other entry fittings must be selected for the installation. Outdoor-rated fittings suitable for a Type 3R enclosure must be used. For installations using two solar cables, our M20 dual cable gland provides a weather-resistant entry point for two cables up to 6mm in diameter. View Dual Cable Gland Are wire connectors or terminal blocks included? The enclosure includes a DIN rail and five-port grounding bar, but application-specific terminal blocks, wire connectors and splicing components are not included. These components must be appropriately rated for the system voltage, current and conductor sizes. What does a Type 3R enclosure rating mean? Type 3R indicates an outdoor enclosure designed to provide protection against falling rain, sleet and external ice formation. It is not intended for submersion or high-pressure water exposure, and all fittings and cover hardware must be installed correctly to maintain the rating. It is not a requirement, but it is recommended to install the JB under a panel to offer additional weather protection. Does the enclosure need to be grounded? The polycarbonate enclosure is nonconductive and does not itself require grounding. However, it also cannot provide electrical bonding between metal conduit fittings. Any required equipment grounding conductors, bonding jumpers or grounding components must be installed separately. What conductor sizes can be used? The enclosure supports copper conductors from 14 to 6 AWG with insulation rated for at least 75°C. The allowable range of an individual terminal block or wire connector may be narrower, so every connection component must be verified separately. What's the max voltage solar array? The JB-3 is rated for PV systems up to 1,000V and 80A max. All fittings, conductors, terminal blocks and connectors installed inside the enclosure must also be appropriately rated for the highest system voltage present. Need Help With Your Rooftop Wiring? Contact us if you need help confirming Kinetic rail or Unistrut compatibility, or selecting the appropriate PV wire, fittings and grounding or bonding components for your installation. Contact Us Shop Solar Racking