SANS 10142-1:2024 — What Farmers Need to Know

What Is SANS 10142-1?

SANS 10142-1 is the South African National Standard for the wiring of premises, commonly known as the "Wiring Code." It covers all low-voltage electrical installations in South Africa, including residential, commercial, industrial, and agricultural properties. The 2024 edition is the latest revision and introduces several changes that are relevant to farm owners, particularly those with solar installations.

Compliance with SANS 10142-1 is a legal requirement. All electrical installations must have a valid Certificate of Compliance (CoC), and any modifications, including the addition of solar systems, require the installation to be inspected and certified by a registered electrician.

Key Changes in the 2024 Edition

The 2024 edition includes updated requirements for renewable energy installations, including clearer specifications for the integration of solar PV systems with existing farm electrical infrastructure. This covers aspects like DC isolator placement, cable sizing for solar strings, and earthing requirements for ground-mounted solar arrays.

There are also updated requirements for surge protection devices (SPDs). Farms are particularly vulnerable to lightning damage due to their rural locations and large roof areas. The new standard provides more detailed guidance on SPD selection and installation for solar systems, which is critical for protecting your investment.

The standard now provides more specific requirements for battery energy storage systems (BESS). As battery installations become more common on farms, the wiring code addresses cable sizing, isolation switching, ventilation, and fire safety considerations specific to lithium-ion and lithium-iron-phosphate battery systems.

What This Means for Existing Installations

If your farm's electrical installation was certified under an earlier edition of the standard, it remains valid. You do not need to upgrade your entire installation to comply with the 2024 edition. However, any new work, including adding a solar system, must comply with the current standard.

This is an important consideration when planning a solar installation. If your farm's existing electrical infrastructure is outdated or non-compliant, the solar installer may need to address certain issues before the solar system can be connected and certified. Common issues include undersized main breakers, missing earth leakage protection, and inadequate distribution board capacity.

A reputable solar installer will assess your existing infrastructure as part of the design process and advise on any upgrades that are needed.

Solar-Specific Requirements

For grid-tied solar installations, the standard requires proper anti-islanding protection, meaning the system must shut down automatically when the grid fails (unless it is a hybrid system designed for backup operation). This prevents the solar system from feeding power back into the grid during maintenance, which could endanger Eskom technicians.

DC isolators must be installed at the solar array and at the inverter. These must be rated for DC operation, as AC-rated isolators are not suitable for the DC voltages generated by solar panels. This is a common compliance issue that we see on installations done by less experienced contractors.

Earthing requirements for solar installations are detailed and specific. Both the DC and AC sides of the installation must be properly earthed, and ground-mounted arrays require their own earthing system connected to the main earth of the property.

Certificates of Compliance

Any solar installation on your farm requires a CoC issued by a registered electrician. This certificate confirms that the installation complies with SANS 10142-1 and is safe to operate. Without a valid CoC, your insurance may not cover damage or losses related to the electrical installation.

When choosing a solar installer, verify that they work with registered electricians who can issue the necessary certificates. At Off Grid Engineering, every installation is signed off by a registered professional, and we ensure full compliance with the current edition of the standard.