- String Junction/combiner box is to be provided on DC power side to collect the electrical power from the strings.
- String Junction Box shall be stand alone units to be erected nearer to modules at an optimized distance to reduce the DC losses.
- The box enclosure is dust, vermin and water proof, impact resistant. The box is having IP 66 protection for enclosure and protection class II.
- The Box of polycarbonate material with resin free material offering fire resistance and anti-hygroscopic nature.
- All terminals inside the String/Array junction box are of copper and connected to copper bus bar of proper size to reduce Internal ohmic and heat losses.
- The String/Array junction box have suitable cable entry points fitted with MC- 4 compatible connectors.
- Each string input is protected with suitable fuse to prevent the fault current feeding in reverse direction with suitable arrangement of isolation and connection.
- All fuses have fuse holder for human protection with fuse blown indication.
- The strings can be isolated during live condition with fuse folders thus avoiding generation loss.
- SCB provided with suitable SPD of Type I & II of MOV type between positive and negative buses and earth to protect the system against lightning and switching surges.
- DC PHOTOVALTIC fuse will be provided on positive side of each strings if system is with negative grounding. (Both side fuse protection system is also available on demand)
- The fuse rating should be so designed that it should protect the string and module from high reverse current flow and derated for ambient temperature.
- Each design tested for temperature rise test. Maximum temperature rise permitted is 30°C over an 50°C ambient temperature.
Features and benefits
SCB Technical features
| S. No. | Item Description | TRI-8| TRI-12| TRI-16| TRI-4 |
|---|---|---|
| 1. | Enclosure Detail | |
| String Inputs (+ve & -ve) | 8+8|12+12|16+16|24=24 | |
| Ingress Protection for Enclosure with Front Cover | > IP 65 | |
| Enclosure Maker | Tricare | |
| Type of material used in Enclosure | Polycarbonate | |
| Rated Service Voltage | 1500V DC or 1000V DC | |
| Impact Protection | >= IK 08 | |
| Mounting | Structure mounting | |
| Installation | Outdoor | |
| Colour | White Polycarbonate | |
| 2. | Ambient Condition | |
| Operation Temperature | -25… + 50°C | |
| Storage Temperature | -25… + 60°C | |
| Relative Air Humidity | up to 95%, Non Condensing | |
| 3. | DC Input | |
| Input Cable Entry Powder Cable | Polycarbonate Cable Gland | |
| Input Cable Connection Strings | Mc4 Connectors | |
| Fuse Type | Cylindrical | |
| Fuse Current Rating (A) | As per string input required | |
| 4. | DC Output | |
| Output Cable Gland | 240 to 400sqmm as per cable design | |
| Clamping Area | 70-120 | |
| Conductor Material | CU / AL | |
| Terminal Type | Ring Terminal | |
| Voltage DC | 1000V DC/1500V DC | |
| Maximum Current output | As per design from 100 to 400Amps | |
| 5. | DC Output | |
| Monitoring | Visual for fuse blown and SPD blown | |
| 6. | Components | |
| Surge Protector | Type (I + II ) 1500V Isc PV, 10kA | |
| DC Disconnector Switch (1500V ) | Yes ( Rating as per Design ) | |
| Breather | Yes | |
| 7. | Applicable Standard | |
| Fire Resistance | UL 94V | |
| UV Resistance | UL 746C | |
| Mechanical Impact Resistance | IEC 62262 | |
| Surge Protection | EN 50539-11 | |
| Enclosure for Low Voltage Switchgears & control Gear assemblies | IEC 62208 | |
| Overall applicable standard for complete SCB | EN 60439 | |
| PV Connectors | IEC 62852 | |
| PV Cables | EN 50618 | |
| DC Switch | IEC 60947 – 1 & 3 | |
| 8. | DC Output Switch | Socomac/Telergon/ABB |
SLD
Wiring Diagram
