MidNite Solar 12 String 3 Output Combiner For Multi-MPPT Solar Inverters - NEMA 3R Outdoor Rated
SKU: MNPV4BY3
Product Summary
The MidNite Solar MNPV4BY3 combines up to 12 solar panel strings into three independent outputs, each carrying four strings to a separate MPPT input on your inverter or charge controller. NEMA 3R outdoor rated aluminum enclosure with all 12 touch-safe fuse holders and 30A fuses included.
Specifications:
- Combines 12 solar strings into three independent 4-string outputs
- 1000VDC maximum system voltage, 30A per string
- 12x touch-safe DIN rail fuse holders with 30A fuses included (10x38mm)
- Three independent 120A tin-plated copper output busbars with separate negative returns
- NEMA 3R aluminum enclosure for outdoor installation
- SGS Listed to UL 1741 for USA and Canada
Log in to check member price and detailed stock information.
We are working on restocking this item
Log in to see additional stock details
Current Connected is YOUR MidNite Solar product specialist
About the MidNite Solar 12 String 3 Output Combiner
The MidNite Solar MNPV4BY3 is a 12-string PV combiner built for inverters and charge controllers with multiple MPPT inputs. Instead of combining all 12 strings down to a single output like a standard combiner, this box keeps strings separated into three independent groups of four. Each group feeds its own MPPT input, which means the inverter can track each group independently for maximum harvest. This is the right combiner for multi-MPPT inverters like the EG4 12000XP or any system distributing strings across three separate charge controllers.
Fusing and Overcurrent Protection
The combiner includes 12 DIN rail-mounted touch-safe fuse holders loaded with 30A fuses (10x38mm). The touch-safe design meets IEC finger-safe standards, allowing fuse replacement without exposing live terminals. Each fuse holder accepts #14 to #6 AWG conductors on the string input side. Individual string fusing means you can isolate a single string for troubleshooting or maintenance without shutting down the entire array.
Independent Outputs and Busbars
Three separate 120A tin-plated copper busbars each combine four strings into one output. Critically, each group also has its own independent negative busbar, so positive and negative returns stay separated per MPPT input without needing external negative combining. Output terminals on each busbar accept #6 to #2/0 AWG cables, sized for the combined current of four parallel strings. A chassis ground busbar accepts conductors up to #1/0 AWG for equipment grounding.
Enclosure and Installation
The NEMA 3R powder-coated aluminum enclosure is rated for outdoor installation. A plastic deadfront covers all live terminals after wiring, providing additional protection against accidental contact. The enclosure mounts vertically or at angles up to 14 degrees from vertical for sloped roof installations. Twelve strain reliefs are included for incoming PV cables, and multiple knockout configurations on the bottom and side panels accommodate both individual string entries and larger conduit runs to the inverter.
Certifications and Warranty
The combiner is SGS Listed to UL 1741 for USA and Canada, covering use in systems up to 1000VDC for both grid-tied and off-grid applications. MidNite Solar manufactures it in Arlington, Washington with a 5-year warranty.
Recommended Accessories
Stäubli Classic MC4 & MC4-Evo 2 Connectors, Rated for 1100V and 35A, 5 Pair Bundle, Options Support 4.7mm to 8.8mm Wire Jacket Diameter
Stäubli's PV connectors, available in Original MC4 and MC4-Evo 2, has 3 sizes for varying PV wire diameters for a secure, watertight connectionFrequently Asked Questions
If your inverter has multiple MPPT inputs, you want to keep string groups separated so each MPPT can track independently. A single-output combiner merges everything into one pair of wires, which defeats the purpose of having multiple MPPTs. This combiner keeps three groups of four strings isolated from the array all the way to the inverter.
No. You can use fewer strings per group or leave entire groups unused. For example, you could run three strings on two outputs and leave the third output empty. Unused fuse positions simply stay open.
Any inverter or charge controller setup that accepts up to three separate PV inputs at 1000VDC or below. Common examples include multi-MPPT inverters with three PV inputs, or systems using three independent charge controllers. Check your inverter's maximum input current per MPPT to make sure four paralleled strings don't exceed it.
Yes. All 12 fuse holders come loaded with 30A fuses (10x38mm). If your strings require a different fuse rating, 10x38mm PV fuses are a standard size and readily available.
NEC 690.9 requires PV string overcurrent protection to be rated at no less than 1.56 times the module's short-circuit current (Isc). Check your panel's Isc on its datasheet, multiply by 1.56, and select the next standard fuse size at or above that number. The included 30A fuses cover most standard residential panels.
Yes. The NEMA 3R enclosure is outdoor rated, and it can mount vertically or at angles up to 14 degrees from vertical. Twelve strain reliefs are included for securing incoming PV cables.
Yes. Each of the three output groups has an independent negative busbar, so you don't need external negative combining. Positive and negative for each MPPT input stay fully separated inside the box.
Customer Reviews
No reviews yet. Be the first to review this product!