Solar ACDB and DCDB panels: IP65, IEC 61439, CPRI type-tested
A Solar ACDB (AC Distribution Board) sits between the inverter and the load or grid connection: it isolates, protects and meters the inverter output, combines several string inverters onto one busbar and gives the O&M team a safe switching point. A Solar DCDB (DC Distribution Board) — also called an array junction box or string combiner — collects the PV strings, protects each with a gPV fuse, adds Type 1+2 surge protection and a DC isolator, and feeds the inverter. Accu-Panels Energy manufactures both in IP65 enclosures to IEC 61439 on a CPRI type-tested platform for rooftop, ground-mount and MW-scale plants, from its Ahmedabad works, and exports them across Africa and the Middle East.
Solar ACDB specifications
| Parameter | Range |
|---|---|
| Rated voltage | 415 V AC (rooftop and central inverters) or 800 V AC (string-inverter MW plants), 3-phase 50 Hz |
| Rated current | 63 A single-inverter ACDB to 6300 A main ACDB / 800 V LT panel |
| Short-time withstand | 25 kA to 65 kA for 1 s per project fault level |
| Switchgear | MCB / MCCB / ACB per inverter output, main incomer MCCB or ACB, Type 2 (or 1+2) AC surge protection device, optional contactor for anti-islanding trip |
| Metering & monitoring | Multifunction meter with Modbus RTU / TCP, CTs class 0.5 / 1, provision for net meter or ABT meter, NVR protection where required by the DISCOM |
| Enclosure | IP65 CRCA (2.0 / 1.6 mm) with 7-tank pre-treatment and C5 anti-corrosion coating, or IP66 polycarbonate for small rooftop units; canopy for outdoor sites |
| Standards | IEC 61439-1/2, IEC 60947, IEC 60529, IEC 61643-11 (SPD); CPRI type-tested design |
Solar DCDB / array junction box specifications
| Parameter | Range |
|---|---|
| System voltage | 1000 V DC or 1500 V DC |
| Strings in / out | 2 in / 1 out up to 24 in / 1 out (or 2 out for dual-MPPT inverters) |
| String protection | gPV fuses 10 A–32 A (IEC 60269-6) in touch-safe fuse holders, positive and negative |
| Surge protection | Type 2 DC SPD (Type 1+2 for exposed sites) per IEC 61643-31, 1000 / 1500 V DC |
| Isolation | DC-rated load-break isolator, 32 A to 630 A, IEC 60947-3 |
| Enclosure | IP65 / IP66 polyester (SMC), polycarbonate or CRCA; UV-stabilised; MC4 or gland entries; optional string monitoring |
Selection guide
- Rooftop up to 100 kW: polycarbonate IP65 ACDB with MCB per inverter and Type 2 SPD; DCDB integrated in inverter or a 2-in/1-out AJB per MPPT.
- Industrial rooftop 100 kW–1 MW: CRCA IP65 ACDB with MCCB per inverter, main MCCB, MFM and NVR relay; AJBs with 4 to 8 strings and monitoring.
- Ground-mount MW-scale with 800 V string inverters: 800 V AC combiner ACDBs feeding an 800 V LT panel at each inverter transformer, C5-coated, SCADA-ready. See our MW-scale solar ACDB design guide.
Related solar panels
Array junction box · AC combiner box · AC distribution board · DC distribution board · NVR panel · TVM metering panel · DG–solar synchronising · How ACDB and DCDB work in a solar plant
Frequently asked questions
What is the difference between an ACDB and a DCDB?
The DCDB (array junction box) sits on the DC side between PV strings and the inverter, providing string fuses, DC surge protection and a DC isolator. The ACDB sits on the AC side between the inverter and the load or grid, providing AC breakers, AC surge protection, metering and isolation.
Which SPD type do I need?
Type 2 SPDs are standard on both DC and AC sides. Type 1+2 is used where the array or building has an external lightning protection system or is in a high-exposure area.
Why IP65?
IP65 (dust-tight, protected against water jets) is the practical minimum for rooftop and open-field solar equipment in Indian monsoon and dust conditions. IP66 polyester is used for small outdoor AJBs.
Can you supply ACDBs for 800 V string inverters?
Yes. 800 V AC combiner ACDBs and 800 V LT panels are an Accu-Panels speciality, with switchgear rated for 800 V and CPRI type-tested busbar systems.
Do you provide string monitoring?
Yes. AJBs can be supplied with string-current monitoring units communicating over Modbus RTU / RS-485 to the plant SCADA.
Send your plant capacity, inverter model and string configuration to our solar team for a datasheet and quotation.
