Array Junction Box (AJB) Manufacturer in Vadodara, India

An array junction box (AJB) combines the DC output of several PV strings into one organised, protected connection point, mounted on or near the array structure itself. String cables land in the AJB first — each on its own DC fuse — a DC surge protection device shunts lightning-induced surges at the closest possible point to the modules, and a disconnector lets the whole string group be isolated for maintenance without touching the rest of the array.

Wisdom Techno Solutions builds AJBs at our Vadodara works in UV-stable polycarbonate or powder-coated steel enclosures, IP65 for open structure mounting, with MC4 connectors and glands sized to the actual string cable schedule. Devices conform to IEC 60947 and IS 8623, and the assembly follows IEC 61439-1 practice and MNRE guidelines. Because the AJB lives outdoors on the structure — the harshest location any board in the plant occupies — enclosure execution and gland-plate detail matter as much as the electrical bill of material.

• DC fuse per string in touch-safe holders, rated for string current and system voltage
• DC surge protection device at the closest point to the array — where it does the most good
• DC isolator so a string group is isolated without shutting the plant
• UV-stable, weather-resistant enclosures with proper gland-plate detail
• MC4 plug-in cabling — strings connect and disconnect without opening terminations
• Labelled per string to the drawing, so fault-finding on the roof is not guesswork

The table below is the standard build. String count, fuse rating and SPD class are set from the array layout, the string voltage at the lowest site temperature and the plant's lightning-protection design.

Small rooftop plants sometimes merge the two jobs into one box; larger plants keep them separate so a structure-level fault is isolated at the structure. The DC-side chain is: strings → AJB → DCDB → inverter, and the whole package is described on the solar BOS electrical package page.

The array layout (strings per AJB, modules per string), the string voltage at the lowest expected site temperature and the string short-circuit current, the mounting location (structure, wall, height), the SPD class from the lightning-protection design, and the cable and connector schedule. With these the box is engineered without assumptions — send them through the Get a Quote form.

• Fuse rating copied from the module STC current — it must account for irradiance enhancement and the fuse manufacturer's derating
• SPD omitted "because the DCDB has one" — the AJB sits closest to the modules and sees the induced surge first
• IP54 specified for open structure mounting — an AJB in the open needs IP65 and UV-stable material
• Glands sized before the cable schedule is final — re-drilling a sealed enclosure on the roof costs the IP rating
• No string labelling requirement — unlabelled boxes turn every string fault into an afternoon of measurement

AJBs are built at the Kotambi works with the same discipline as our LT switchboards: devices per the approved bill of material, wiring verified against the drawing, insulation resistance and functional checks in routine testing, and the test report shipped with the boxes. Repeat orders for the same plant design ship against the proven drawing, which is what solar EPCs running multiple sites actually need.

• BESS Electrical Panel Design — PCS, ACDB & DCDB — the same boards in battery-coupled plants
• Panel Earthing & Earth Busbar Design — earthing practice these boards must follow
• FAT & Routine Test Checklist — what is checked before any board leaves the works
• LT Panel Specification & RFQ Guide — how to specify a board so quotes are comparable

If this is not the right fit for your layout, these are the related products we build to the same standard:

• Solar DCDB — the next board downstream — combines AJB outputs to the inverter
• Solar ACDB & DCDB — the AC and DC distribution pair of the plant
• AC Combiner Box — the AC-side equivalent — collects inverter outputs
• Solar BOS Electrical Package — the complete solar board package from one works

Email your single line diagram, load list and system fault level and our engineers will come back with a technical offer. Not sure what to send? See what a panel manufacturer needs in order to quote accurately.

Page updated: 17 September 2026