How do you ensure the quality of your solar systems once contractors deliver them to you?

This article outlines what we do to ensure the quality of the installation of our solar plants and the criteria of our acceptance of the completed installation in order for systems to reach Commercial Operation.

Ensuring the quality of our solar system, and thus the efficiency of cell performance, requires intensive quality management. There are a number of rigorous tests that we run from start to finish. They're divided into two main categories.

Mechanical installation:
  • We receive on-site quality assurance documentation to ensure that the Contractors have checked for any mechanical errors during the installation (i.e. all mounting structure bolts and electrical terminations are torque marked; DC and AC connections are secure; cable trays and covers are secure; earthing cables are continuous, etc.)
  • We conduct a final inspection at the end of the installation to verify the Contractor’s checks
Electrical installation:
  • During the final inspection, the equipment installed is checked against the approved design (i.e. modules are Tier 1 and as per design; inverter is NRS-097 approved)
  • We receive the Contractor’s commissioning test reports which include:
    • PV module stringing tests (voltage and current testing for each string)
    • Insulation resistance testing for each string
    • Earth resistance testing for the mechanical installation (modules to mounting structure to cable tray to equipment to earth point at the main distribution board)

  • A Certificate of Compliance is provided by a registered person with the requisite authority
  • A Professionally registered Engineer with ECSA (Engineering Council of South Africa) signs off on the installation with an independent commissioning report, as per municipality approved forms
  • A Performance Ratio test is conducted at the end of the installation for 5 days. This test ultimately measures how effective the plant converts sunlight into energy delivered to the energy user, and takes into account the building installation quality (inverter efficiency; wiring; pv module performance; shading; component failures etc.) and also the site environmental conditions (i.e. site specific irradiance and temperature measurements). Each site is subject to different conditions (roof orientation and angle, roof materials affecting temperature of modules etc.) and each site is analysed for an expected Performance Ratio. With the expected Performance Ratio analysed (using the design data), the Contractor’s conduct a 5-day test at the end of the project to demonstrate that the Plant passes.
  • More information on Performance Ratio, by the National Renewable Energy Laboratory (NREL) below:

Last but certainly not least, in addition to the above, we have created a Contractor's Project Manual that describes in detail what we want them to design for us, and how we want these systems installed, so that they are also working towards a common goal, and quality expectation.
Please feel free to reach out to us if you have any questions.