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1kWp set

Installation Instructions - Qualified Electrician

General information

What is the SSB and what does it do ?
The solar switch box (SSB) connects the 8 SRT strings (12 SRT = 1 string) At this stage the string voltage is under a harmless 75 V DC.
SSB Construction:
CE, safety class system II, system voltage 300 V DC suitable for indoor humid conditions, flame retardent 180x130x35 mm housings with transparent cover, SSB for 96 SRT (1kWp)

The Electrician

The electrical installation may be only carried out by a licensed electrician.
The electrician is responsible for the installation from the solar switch box to the grid. He must know all the regulations, stipulated by the power company, in regard to grid connected pv installations.

The Electrical Check

The electrician is required to make an electrical check before the installation starts.
He will..
  1. Specify the ideal DC connection between the solar switch box and inverter (check your inverter manual from the manufacturer). Note: The inverter must be installed as close as possible to the solar switch box and should be located in a well ventilated place, protected from light and humidity.
  2. Determine the best AC connection between the inverter and the power grid, and also know all the necessary equipment recommended by the regional power company, like electric meter, safety fuses, ENS de-energizing devices etc.
  3. Inform your power company about the pv installation.
  4. Submit an application for any subsidies offered by your power company or regional authorities.

Solar Switch Box Installation

The SSB is already mounted under the roof by the roofer near the cable inlet. This must be a dry, accessible place without direct exposure to the sunlight.

The SSB is not allowed to be opened by anyone other than a qualified electrician.

If a string (12 SRT) is correctly assembled and connected, the appropriate red indication lamp will light up inside the SSB (only during daylight hours). All 8 lamps should be lit up before continuing.

Electrical Assembly

First check in the inverters manual what the input voltage level is:
120 Volt or 240 Volt. (open circuit voltage of the pv generator)

The cover of the SSB is opened. To measure the voltage of the strings follow the diagram below.

Click on the image for a detailed view

string test

The necessary voltage level is then achieved by bridging.
Note: the bridges can be supplied with the SSB upon request, or made easliy by yourself from cable lengths.
This diagram below shows two of the bridge configurations possible.

Click on the image for a detailed view


240 VDC/6A
Bridges B-E; C-F; D-G
Output cable 2, 5mm²
120 VDC/12A
Bridges A-B; C-D; E-F; G-H; D-E
Output cable 4mm²
Output cable terminals:
A: - minus
H: + plus
After the bridges have been correctly configured it is important to close and secure the SSB. This is done by the removing the housing screws, this will prevent any "toolless" entry by unauthorized persons.
Multiple SSB's must be switched in parallel. We recommend connecting the SSB to the DC main cable through an additional case (commercial standard, and not supplied), since the output terminals of the SSB are only suitable for cables up to 4mm². The DC cabling to the inverter can have a substantially greater diameter, this prevents voltage loss over longer distances. This can only be determined when the distance from the SSB to the inverter is set and calculated.
Documentation is important during the installation. All necessary warning signs and circuit labels must be done and conform with the use of a grid connected pv installation.
Establish the AC installation by the information gathered by the electrical check. (electric meter, AC de-energizing device, etc..) Install the inverter following the regulations and the operating and assembly instructions from the inverter manufacturer.
Lastly inform your power company about the installation.
Last updated: 13:03:03 all subject to change without notice