Solar PV Combiner Box Configuration Diagram

Photovoltaic Protection Box – Technical Configuration

System Overview

Product by: Kuangya Electrical Equipment Supply (cnkuangya.com)

The PV Combiner Box is a critical component in solar installations, providing centralized DC protection, monitoring, and connection management for multiple PV strings before feeding into the inverter.


Configuration Diagram

┌─────────────────────────────────────────────────────────────────────┐
│                    PV COMBINER BOX (IP65 Enclosure)                 │
│                        Model: KYDB Series                            │
│                     www.cnkuangya.com                               │
├─────────────────────────────────────────────────────────────────────┤
│                                                                       │
│  ┌─────────────────  INPUT SECTION (DC+/DC-)  ──────────────────┐  │
│  │                                                                 │  │
│  │  String 1:  [+]─┤Fuse gPV 14×85├─┤SPD├─┐                     │  │
│  │                                            │                     │  │
│  │  String 2:  [+]─┤Fuse gPV 14×85├─┤SPD├─┤                     │  │
│  │                                            │                     │  │
│  │  String 3:  [+]─┤Fuse gPV 14×85├─┤SPD├─┤  DC Bus (+)         │  │
│  │                                            │                     │  │
│  │  String 4:  [+]─┤Fuse gPV 14×85├─┤SPD├─┤                     │  │
│  │                                            │                     │  │
│  │  String 5:  [+]─┤Fuse gPV 14×85├─┤SPD├─┤                     │  │
│  │                                            │                     │  │
│  │  String 6:  [+]─┤Fuse gPV 14×85├─┤SPD├─┘                     │  │
│  │                                                                 │  │
│  │  ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─   │  │
│  │                                                                 │  │
│  │  String 1:  [-]─────────────────────┐                         │  │
│  │  String 2:  [-]─────────────────────┤                         │  │
│  │  String 3:  [-]─────────────────────┤  DC Bus (-)             │  │
│  │  String 4:  [-]─────────────────────┤                         │  │
│  │  String 5:  [-]─────────────────────┤                         │  │
│  │  String 6:  [-]─────────────────────┘                         │  │
│  │                                                                 │  │
│  └─────────────────────────────────────────────────────────────────┘  │
│                                                                       │
│  ┌────────────────  PROTECTION SECTION  ─────────────────────────┐  │
│  │                                                                 │  │
│  │   DC Bus (+) ──┤DC Circuit Breaker KYDB-63├─┐                │  │
│  │                     (1500V, 63A)              │                │  │
│  │                                                │                │  │
│  │   ┌──────────────────────────────────────────┘                │  │
│  │   │                                                             │  │
│  │   │    ┌─────────────────────────────────┐                    │  │
│  │   ├────┤  DC Surge Protector (SPD)       │                    │  │
│  │   │    │  Type 1+2, 1500V DC              │                    │  │
│  │   │    │  Imax: 40kA, In: 20kA            │                    │  │
│  │   │    └─────────────────────────────────┘                    │  │
│  │   │                      │                                      │  │
│  │   │                      ├──── PE (Ground)                     │  │
│  │   │                                                             │  │
│  │   │    ┌─────────────────────────────────┐                    │  │
│  │   └────┤  DC Switch Disconnector          │                    │  │
│  │        │  Load Break Switch               │                    │  │
│  │        │  Manual Operation                │                    │  │
│  │        └─────────────────────────────────┘                    │  │
│  │                      │                                          │  │
│  │   DC Bus (-) ───────┴────────────────────────────────────┐    │  │
│  │                                                            │    │  │
│  └────────────────────────────────────────────────────────────────┘  │
│                                                                       │
│  ┌─────────────────  OUTPUT SECTION  ────────────────────────────┐  │
│  │                                                                 │  │
│  │   DC Output (+) ────────────────────→  To Inverter (+)        │  │
│  │                                                                 │  │
│  │   DC Output (-) ────────────────────→  To Inverter (-)        │  │
│  │                                                                 │  │
│  │   PE (Ground)   ────────────────────→  Equipment Ground       │  │
│  │                                                                 │  │
│  └─────────────────────────────────────────────────────────────────┘  │
│                                                                       │
│  ┌─────────────────  MONITORING SECTION  ────────────────────────┐  │
│  │                                                                 │  │
│  │   • Voltage Monitoring (DC+ to DC-)                            │  │
│  │   • Current Monitoring (per string)                            │  │
│  │   • Temperature Sensors                                        │  │
│  │   • SPD Status Indicator (Red Light = Fault)                  │  │
│  │   • Communication Port (RS485/Modbus)                          │  │
│  │                                                                 │  │
│  └─────────────────────────────────────────────────────────────────┘  │
│                                                                       │
└─────────────────────────────────────────────────────────────────────┘

Component Specifications

1. PV String Fuses (gPV Type)

  • الطراز: gPV 14×85 mm
  • Rating: 10A – 30A (depending on string current)
  • الفولتية: 1000V / 1500V DC
  • القدرة الاستيعابية: High interrupting rating for DC applications
  • Function: Overcurrent protection for individual PV strings
  • الميزات: UV-resistant, replaceable modules

2. DC Surge Protection Device (SPD)

  • النوع: Type 1+2 Combined
  • تصنيف الجهد: 1500V DC
  • Maximum Discharge Current (Imax): 40kA (8/20μs)
  • تيار التفريغ الاسمي (بوصة): 20kA
  • Protection Level (Up): < 4kV
  • Status Indication: Visual indicator window (Red = Failure)
  • Function: Lightning and surge protection

3. قاطع دارة التيار المستمر

  • الطراز: KYDB-63 Series
  • التيار المقنن: 16A – 63A
  • الفولتية المقدرة: 1000V / 1500V DC
  • الأعمدة: 2P (Positive and Negative)
  • القدرة الاستيعابية: 10kA – 20kA DC
  • Function: Overload and short-circuit protection, manual isolation
  • الميزات: Arc extinction technology for DC applications

4. مفصل تبديل التيار المستمر

  • النوع: Load Break Switch
  • Rating: Up to 63A, 1500V DC
  • العملية: Manual rotary handle
  • Function: Safe isolation for maintenance
  • الميزات: Lockable in OFF position, visible contact gap

5. Enclosure

  • Material: Powder-coated steel or UV-resistant plastic
  • تصنيف الحماية: IP65 (dust-tight, water jet protected)
  • التركيب: Wall-mount or pole-mount options
  • Cable Entry: Bottom entry with cable glands
  • Dimensions: Customizable based on string quantity

Technical Parameters

المعلمةالمواصفات
Max Input Strings6 – 16 (customizable)
جهد النظام1000V / 1500V DC
Max Input Current per String15A – 20A
Total Output CurrentUp to 400A
درجة حرارة التشغيل-40 درجة مئوية إلى +70 درجة مئوية
الارتفاع≤ 2000m (standard), higher available
Compliance StandardsIEC 60947, IEC 61643-31, CE, RoHS
الضمان5 سنوات قياسية

Protection Features

String-Level Protection

Each PV string is individually protected with gPV fuses and SPDs, preventing fault propagation between strings.

Surge Protection

Type 1+2 SPD provides comprehensive protection against direct and indirect lightning strikes, as well as switching surges.

Overcurrent Protection

DC circuit breakers protect the main bus and downstream equipment from overload and short-circuit conditions.

Isolation Capability

Switch disconnector allows safe maintenance with visible contact separation and lockout capability.

Reverse Polarity Protection

Blocking diodes or fuse coordination prevents reverse current flow during shading or module mismatch.


Installation Guidelines

  1. Location Selection
  • Install close to PV array to minimize DC cable runs
  • Ensure adequate ventilation and shade from direct sunlight
  • Accessible for maintenance and inspection
  1. Wiring Requirements
  • Use UV-resistant DC cables (PV1-F or equivalent)
  • Proper cable sizing based on string current and voltage drop
  • Secure cable glands to maintain IP65 rating
  1. Grounding
  • Connect enclosure to equipotential grounding system
  • Ensure SPD ground lead is as short as possible (< 0.5m)
  • Use copper grounding conductors (min. 16mm²)
  1. Labeling
  • Clear identification of each string input
  • Warning labels for DC voltage hazards
  • Operation instructions on enclosure door

جدول الصيانة

IntervalMaintenance Task
شهرياًVisual inspection of SPD status indicators
ربع سنويCheck for loose connections, clean enclosure
سنوياًThermal imaging scan, torque verification
As NeededReplace failed SPDs, blown fuses

Quality Assurance

Kuangya Electrical Commitment:

  • ✓ Factory acceptance testing (FAT) before shipment
  • ✓ IEC, CE, RoHS compliance certification
  • ✓ Rigorous thermal cycling and voltage stress tests
  • ✓ Comprehensive technical documentation
  • ✓ Global technical support and spare parts availability

For detailed specifications, customization, or quotation:

Kuangya Electrical Equipment Supply\
Website: cnkuangya.com\
Product Line: DC Photovoltaic Protection Systems\
Experience: 25+ years | 2000+ projects delivered worldwide


This configuration represents a standard 6-string PV combiner box. Configurations can be customized for 8, 12, 16, or more strings based on project requirements.