Solar AC combiner boxes: 415 V and 800 V AC, IP65, IEC 61439
An AC combiner box parallels the outputs of several string inverters onto one busbar so a single cable runs to the ACDB, LT panel or inverter transformer. Each inverter input has its own MCB or MCCB, the combined output has a main breaker, and a Type 2 AC surge protection device protects the inverters from switching and lightning surges. Accu-Panels Energy builds AC combiner boxes for 415 V and 800 V AC string-inverter plants in IP65 CRCA or polyester enclosures to IEC 61439, on the same CPRI type-tested platform as its 800 V LT panels.
AC combiner box specifications
| Parameter | Accu-Panels range |
|---|---|
| Rated voltage | 415 V AC or 800 V AC, 3-phase 50 Hz (690 V on request) |
| Inverter inputs | 2 to 16 inputs, 63 A to 400 A each (MCB / MCCB per inverter) |
| Combined output | MCCB or ACB up to 3200 A; copper or aluminium busbar |
| Short-circuit rating | 25 kA to 65 kA for 1 s per project fault level |
| Surge protection | Type 2 AC SPD per IEC 61643-11 (Type 1+2 for exposed sites), with status contact |
| Metering / monitoring | Optional multifunction meter with Modbus RTU / TCP, CTs, auxiliary contacts for SCADA |
| Enclosure | IP65 CRCA (2.0 / 1.6 mm, 7-tank pre-treatment, C5 coating) or IP66 polyester; canopy and gland plate for outdoor mounting; −10 °C to +55 °C |
| Standards | IEC 61439-1/2, IEC 60947-2, IEC 61643-11, IEC 60529; CPRI type-tested design |
On a string-inverter plant, running a separate AC cable from every inverter to the LT panel is costly and clutters the switchboard. An AC combiner box mounted near the inverter cluster parallels 4 to 16 inverters onto one busbar, gives each inverter its own isolation and protection, and sends a single feeder to the ACDB or 800 V LT panel. The result is lower cable cost, simpler maintenance and a clean interface for metering and SCADA.
- Individual MCB / MCCB per inverter for isolation and back-feed protection
- Main MCCB or ACB on the combined output
- Type 2 AC surge protection with remote indication
- Busbar sized by temperature-rise design verification, tin-plated copper on request
- IP65 outdoor enclosure with canopy, breather and C5 anti-corrosion finish
- Provision for multifunction meter, CTs and SCADA contacts
- Bottom cable entry with gland plate; door-interlocked handles
- Designed to IEC 61439-1/2; CPRI type-tested platform
- 415 V AC or 800 V AC, 3-phase, 50 Hz
- 2 to 16 inverter inputs, 63 A to 400 A each
- Combined output up to 3200 A
- Short-time withstand 25 kA to 65 kA for 1 s
- IP65 CRCA or IP66 polyester enclosure per IEC 60529
Industrial rooftop plants (dairy, plastics, chemical, textile, cold storage, cement), commercial and institutional rooftops, ground-mount and MW-scale plants with 800 V string inverters, solar carports, and hybrid solar-DG installations with DG–solar synchronising.
Frequently asked questions
What is the difference between an AC combiner box and an ACDB?
A combiner box only parallels inverter outputs with per-inverter protection. An ACDB is the distribution board that adds main metering, isolation towards the grid or load, and often NVR / anti-islanding protection. On small plants one box does both jobs; on large plants combiners feed the ACDB or LT panel.
How many inverters can one combiner box handle?
Typically 4 to 16, limited by the output breaker rating (up to 3200 A) and cable practicality. We size it from the inverter rated AC current with a 1.25 factor.
Do you make 800 V AC combiner boxes?
Yes. 800 V AC is our speciality for MW-scale string-inverter plants, with switchgear and busbars rated and type-tested for 800 V.
Is surge protection necessary on the AC side?
Yes. Inverters are sensitive to switching and lightning-induced surges arriving from the grid side; a Type 2 SPD at the combiner is standard practice and required by most EPC specifications.
What is the delivery time?
Standard combiner boxes ship in 2 to 4 weeks; project-specific designs in 4 to 6 weeks after drawing approval.
Send your inverter model, count and site details to our solar team for a combiner box datasheet and quotation.
