What is SANS 10142-1 and why does it apply to solar installations?

SANS 10142-1:2020 is the South African National Standard for the wiring of premises. It is the South African equivalent of the International Electrotechnical Commission's IEC 60364 series. All electrical installations in South Africa — including solar PV systems — must comply with SANS 10142-1. It governs the design, installation, and inspection of electrical wiring, covering both the DC side (PV array wiring) and the AC side (inverter output to distribution board). Compliance is certified by a Certificate of Compliance issued by a DoL-registered electrical contractor.

Does SANS 10142-1 specifically address solar PV installations?

SANS 10142-1:2020 incorporates provisions for PV power supply systems (based on IEC 60364-7-712). These provisions cover: DC circuit protection, string fusing requirements, DC isolator requirements, earthing of the PV array and mounting structure, labelling of DC circuits, and requirements for the point of connection between the PV system and the fixed wiring of the premises. Installers working on solar PV must be familiar with both the general wiring requirements of SANS 10142-1 and the PV-specific provisions.

What are the earthing requirements for solar PV under SANS 10142-1?

SANS 10142-1 requires effective earthing and bonding of all conductive parts that could become live under fault conditions. For solar PV specifically: the PV mounting structure must be bonded to the premises earth, the inverter chassis must be earthed, and exposed conductive parts of the array frame must be bonded together and connected to the main earth. The earthing system must be designed to ensure that fault currents can flow and protection devices can operate to clear the fault. The specific earthing arrangement depends on the inverter topology (transformerless or transformer-isolated) and the array grounding configuration.

What labelling is required for a solar installation under SANS 10142-1?

Required labelling for solar PV installations under SANS 10142-1 and associated standards includes: 'SOLAR PV DC SUPPLY' or equivalent on DC cables and conduit, 'PV ARRAY — DC SUPPLY — DO NOT OPEN UNDER LOAD' on string combiner and DC isolator, warning labels at the main distribution board indicating the presence of a PV system, and emergency shutdown procedure label (or reference to it) near the main isolator. Labels must be durable, legible, and resistant to the installation environment.

What cable types are permitted for DC solar wiring under SANS 10142-1?

DC cables in solar PV applications must be suitable for outdoor use, UV exposure, and the DC voltage of the system. Single-core DC solar cable (often marked PV1-F or H1Z2Z2-K in line with TUV 2 Pfg standards) is the standard choice for string wiring from panels to inverter. Standard PVC-insulated cables are not suitable for exposed DC solar applications — they are not rated for the UV exposure and temperature cycling experienced on rooftop installations. Cables must be correctly sized for the maximum current of the string.

SANS 10142-1 Solar Installation Requirements in South Africa

SANS 10142-1:2020 is the foundation of every solar electrical installation in South Africa. It is not a solar-specific standard — it is the national wiring code that applies to all electrical installations — but it includes provisions specifically for PV power supply systems. Getting SANS 10142-1 compliance right determines whether your installation passes the CoC inspection and satisfies network operator requirements.

This guide focuses on the SANS 10142-1 requirements most relevant to solar PV: DC wiring, protection, earthing, labelling, and the PV-specific provisions that inspectors check.

Standard

SANS 10142-1:2020 — Wiring of premises: Part 1: Low-voltage installations

Published By

South African Bureau of Standards (SABS)

PV-Specific Section

Based on IEC 60364-7-712: Requirements for special installations — Solar photovoltaic (PV) power supply systems

CoC Authority

Department of Labour — Electrical Installations Regulations (OHS Act 85/1993)

Enforced By

DoL-registered electrical contractor (inspection and CoC issuance)

Last Updated

April 2026

DC Circuits Are Live Whenever There Is Light on the Panels

Unlike AC circuits that can be de-energised by switching off a breaker, DC solar circuits remain live as long as sunlight falls on the array. SANS 10142-1 requires isolation means that can safely interrupt the DC current — not just open-circuit it. Ensure DC isolators are rated for the DC break capacity of the system, not just the DC voltage.

SANS 10142-1 Structure for Solar Installers

SANS 10142-1:2020 is a comprehensive standard that covers all types of electrical installation. For solar PV installers, the most relevant sections are:

Section	Relevance
General principles	Fundamental safety requirements applicable to all installations
Cable and conductor sizing	DC string cables, AC output cables — ampacity and derating
Protection against overcurrent	String fusing, DC circuit breakers, AC protection
Protection against earth faults	Earthing system design, RCD requirements
Earthing and bonding	Array structure, inverter chassis, cable armouring
Special installations — PV systems	DC circuit requirements, isolation, surge protection specific to PV
Inspection and testing	What the CoC inspection covers

DC Cable Requirements

Cable Type

Standard twin-and-earth or single-core PVC cables are not appropriate for solar DC applications. The correct cable types for DC solar string wiring:

Cable Type	Application	Notes
PV1-F (or H1Z2Z2-K)	String wiring, panel-to-combiner	UV-resistant, double-insulated, rated for outdoor exposure
Armoured DC solar cable	Underground DC runs	Steel wire armouring for mechanical protection
Standard singles in conduit	Protected DC runs in buildings	PVC singles are acceptable inside conduit, away from UV exposure

Cable Sizing

Size DC cables for:

The module’s Isc × 1.25 as the design current for the cable
Temperature derating based on installation method (free air, in conduit, clipped to surface, bundled)
Maximum voltage drop (typically 1% for DC strings to limit power loss)
The maximum DC system voltage — check cable insulation rating is adequate

DC Overcurrent Protection

SANS 10142-1 and the PV-specific provisions require overcurrent protection in the DC circuit under certain conditions:

Condition	Required Protection
Single string, single inverter input	String fuse not required (Isc cannot exceed cable rating)
Two strings in parallel at combiner	String fuses required to prevent reverse current from exceeding cable rating
Three or more strings in parallel	String fuses required
Main DC cable from combiner to inverter	DC circuit breaker or fuse protecting the main DC cable

DC fuses and breakers must be rated for DC use. The voltage rating must exceed the maximum DC system voltage. AC-rated devices have fundamentally different arc interruption characteristics and are not safe in high-voltage DC solar applications.

Earthing and Bonding Requirements

Array Structure Earthing

The PV mounting structure is exposed metal that could become live under fault conditions. SANS 10142-1 requires:

All metal rail sections to have electrical continuity (verified by conductance testing)
The bonded structure to be connected to the main earth of the premises
The earth conductor to be sized to handle the fault current that could flow

In practice, most aluminium mounting systems achieve conductivity through the mounting hardware — verify with the manufacturer that their hardware provides rated electrical continuity or install supplementary bonding conductors.

Transformerless Inverters and Array Floating

Transformerless string inverters are common in South Africa. These inverters have no galvanic isolation between the DC and AC sides. SANS 10142-1 and inverter manufacturer requirements typically prohibit grounding either the positive or negative DC bus in transformerless inverter installations. The array is left “floating” with respect to earth. This is acceptable — and typically required — for transformerless inverters, but it affects the earthing design.

Labelling Requirements

Label Required	Location	Content
DC cable marking	DC cables throughout installation	”SOLAR PV DC SUPPLY” or equivalent
DC isolator warning	On or adjacent to DC isolator	”PV ARRAY — DC SUPPLY — DO NOT OPEN UNDER LOAD”
Main distribution board warning	At main DB	Warning that a PV system is connected
Emergency shutdown label	Near main isolator	Shutdown procedure reference
String circuit labels	At string combiner	String number, source circuit identifier

Labels must use durable materials appropriate for the installation environment. Adhesive labels in wet or high-temperature areas (cavity roofs) must be rated for the temperature and humidity range.

Produce SANS 10142-1-Compliant Solar Documentation

SurgePV generates the single-line diagrams, cable schedules, and protection device schedules that DoL inspectors check during CoC inspections — all formatted for South African SSEG applications.

Explore the Design Tool

No commitment required · 20 minutes · Live project walkthrough

Common SANS 10142-1 Non-Compliances Found at Inspection

Non-Compliance	Typical Cause
String fuses missing where required	Installer skipped protection design step
DC cable not UV-rated for exposed runs	Standard building cable used on rooftop
Array structure not bonded to earth	Assumed mounting hardware provided continuity without testing
DC isolator not rated for DC break	AC-rated isolator installed on DC circuit
Labels missing or illegible	Labels not installed or applied after weathering
AC isolator not lockable	Standard domestic isolator used instead of lockable version
No surge protection where specified	SPD specified in design but not installed

Frequently Asked Questions

Is SANS 10142-1 the same as IEC 60364? SANS 10142-1 is South Africa’s national adaptation of the IEC 60364 series. It adopts most IEC 60364 requirements with South African modifications. For solar PV, the relevant IEC 60364 part is IEC 60364-7-712 (PV power supply systems), which is incorporated into SANS 10142-1.

Who can purchase SANS 10142-1? SANS 10142-1:2020 is available for purchase from the South African Bureau of Standards at sabs.co.za. The standard is not freely available online. Practicing solar electrical contractors should purchase and maintain access to the current edition.

Does a battery storage addition require a new CoC? Yes. Adding a battery storage system to an existing solar installation is a material change to the electrical installation. A new or amended Certificate of Compliance is required after the battery addition. The battery wiring, protection, and earthing must all meet SANS 10142-1 requirements.

See the Certificate of Compliance guide, the DoL vs ECSA sign-off guide, and the full South Africa compliance overview. Use solar design software to generate compliant system documentation.