SANS 61439 explained: the questions every panel buyer should ask
By Rob Jardine, Chairman, Panel Technique. Technically reviewed by Lloyd Barends, Managing Director, Panel Technique. Last reviewed: 30 October 2026.
Standards referenced: SANS/IEC 61439-1 and -2, SANS 1973-1 and -3, SANS 10142-1, Occupational Health and Safety Act 85 of 1993, Electrical Installation Regulations 2009
The short answer. SANS 61439 governs how low-voltage switchgear and controlgear assemblies (motor control centres, distribution boards, power factor correction panels) are designed, built and verified in South Africa. It makes the panel builder prove that the complete assembly is safe, not only the components inside it. A buyer’s job is to ask for that proof at three points: tender, design and factory acceptance.
I’m not an electrical engineer. I came into this industry from the commercial side, and the first thing I had to get my head around was this standard. This is the explanation I wish I’d had. It is written for plant managers, procurement teams and project engineers who sign off panel purchases. The technical content has been checked by our MD, Lloyd Barends.
What is SANS 61439 and why does it exist?
SANS 61439 is South Africa’s adoption of the international IEC 61439 series for low-voltage switchgear and controlgear assemblies. It exists to answer one question for the owner: has the panel protecting your people and your production line been properly engineered and verified as a complete assembly, or has it simply been put together from certified parts?
Every breaker and contactor is tested by its own manufacturer to its own product standard, the SANS/IEC 60947 series. Put forty of them in a steel enclosure with busbars, cabling and limited airflow, and they behave differently. Heat builds up and fault currents stress the structure. SANS 61439 covers that complete assembly.
In South Africa the standard sits inside a chain of documents:
| Level | Document | Role |
|---|---|---|
| Installation | SANS 10142-1, the wiring code | Requires low-voltage assemblies in an installation to carry evidence of compliance under Table 4.1: a regulatory certificate of compliance or an SABS mark of approved performance |
| National front end | SANS 1973-1, with SANS 1973-3 for assemblies rated at or below 10 kA (typically wall-mounted distribution boards) | South African standard read together with SANS 61439, adding local requirements |
| Base standard | SANS/IEC 61439-1 and -2 | General rules and the design verification method for power switchgear and controlgear assemblies |
What changed when SANS 61439 replaced the old standard?
The old standard, SANS/IEC 60439, classified assemblies into categories: type-tested (TTA) and partially type-tested (PTTA). SANS 61439 removed those categories. Every assembly design must now be verified characteristic by characteristic, using methods the standard permits within set limits, and every finished unit receives routine verification. Routine checks are not new; what has changed is how the design is validated.
South Africa did not simply copy the international model, and for good reason. Full type testing under IEC 60439 would have shut much of the local industry out. Testing every combination at high fault levels is expensive, and the country had very limited facilities able to do it: the SABS National Electrical Test Facility (NETFA) was effectively the only option. At the same time, government policy was to grow new industrial businesses, including firms started by previously disadvantaged entrepreneurs. A test regime that only large or foreign-backed builders could afford would have worked directly against that.
SABS consulted the country’s privately owned panel builders before the standard was introduced, and they raised three problems. Most local builders could not afford full type testing. Imported assemblies, already tested overseas, would have taken over the market. And the cost of entry would have shut out new, previously disadvantaged entrepreneurs. Type testing also locked a builder into a single component brand. As Lloyd puts it, “it just didn’t suit the South African environment.”
The response, in 2003, was SANS 1473-1, mandatory for assemblies rated above 10 kA, which added a third, local category: the specially tested assembly (STA). It kept the market open, but it set a far lower bar than a TTA: as few as three type tests, against seven. Some builders marketed it as if it were equivalent. That gap is exactly what SANS 61439 and its South African front end, SANS 1973-1, close: category labels are replaced by evidence for every characteristic of the design.
IEC 61439 was published internationally in 2009 and has since been adopted in South Africa as SANS 61439. SANS 1473-1 was revised into SANS 1973-1.
| Superseded approach (SANS 60439 / SANS 1473) | Current approach (SANS 61439 / SANS 1973) | |
|---|---|---|
| How compliance is shown | Category label: TTA, PTTA or local STA | Design verification of each characteristic, plus routine verification of each unit |
| Verification methods | Mainly testing | Testing, comparison with a tested reference design, or assessment (calculation and design rules), each within set limits |
| Responsibility | Often blurred between component brand and panel builder | Defined roles for original manufacturer, assembly manufacturer and user |
Who is responsible for compliance under SANS 61439?
Three parties carry defined responsibilities, and one company can hold more than one role. The user or specifier sets the requirements. The original manufacturer designs and verifies the assembly system. The assembly manufacturer builds your panel within that verified design, carries out routine verification on it, and issues the declaration of conformity.
| Role | Usually | Responsible for |
|---|---|---|
| Client / specifier | The client or its consulting engineer | Service conditions and ratings: fault level, rated current, ambient temperature, IP rating. Reviewing the documents received |
| Original manufacturer | A component brand, an enclosure system supplier, or a panel builder with its own verified design | Design verification of temperature rise, short-circuit withstand, dielectric properties, clearances, degree of protection and other characteristics |
| Assembly manufacturer | The panel builder that equips your panel | Building within the verified design, routine verification of each unit, the declaration of conformity |
One rule matters more than the rest. If the assembly manufacturer departs from the original manufacturer’s verified design or instructions, it takes on the original manufacturer’s obligations for that change. The verification does not disappear. Someone has to own it.
Can a panel builder use components from different brands?
Yes, provided the substitution is verified for that specific arrangement. Many South African plants standardise on one component brand, and an independent panel builder can accommodate that. A component’s own certificate is not enough, though. Two devices with similar dimensions and ratings are not automatically interchangeable inside an assembly, because heat and fault behaviour change with the arrangement.
Lloyd Barends, Panel Technique’s Managing Director, explains how this works in practice. When a client wants a breaker or contactor from a different brand inside a verified design, the builder must check that the replacement gives off the same amount of heat or less, and confirm the change against its own tested sample panel. In Lloyd’s words, the builder has to “make sure the heat losses are the same or better.”
Heat is only half of it. The standard allows a device from another manufacturer only where it performs the same or better in every relevant respect. For temperature rise, its power loss and terminal temperature rise must be the same or lower (IEC 61439-1, clause 10.10.3.5). For short-circuit, its breaking capacity must match the assembly rating, its let-through current and energy must be the same or lower, and it must coordinate with the devices around it (clause 10.11.3). Changes to layout, cable entry, cooling or internal segregation go further: they need the design verified again.
What happens when a client’s requirement doesn’t fit the original design?
The change must be verified, and the standard limits how. Calculation and design rules are only allowed within set thresholds; beyond them, the builder needs test data or a tested reference design. Requirements outside the original design are where most compliance risk concentrates, because every change needs its own verification, and the evidence has to cover the arrangement actually being built.
Real sites rarely match a catalogue. Substations are cramped and cable trenches are fixed. As Lloyd puts it, people sometimes realise late that “there’s a little staircase in the corner that they need to try and fit a panel under.”
The limits that matter most:
- Short-circuit withstand. Circuits rated up to 10 kA rms, or protected by current-limiting devices with a cut-off current up to 17 kA peak, are exempt from short-circuit withstand verification (IEC 61439-1, clause 10.11.2). Above that, verification is by test or by comparison with a tested reference design.
- Temperature rise. Verification by calculation is limited to 630 A for single-compartment assemblies and 1,600 A for multi-compartment assemblies (IEC 61439-1, clauses 10.10.4.2 and 10.10.4.3). Above that, test data or a tested reference design is needed.
Sometimes the right answer is no. “We’re not just going to do something for the sake of pleasing the client,” Lloyd says. “We’ve got a responsibility to the industry and to our clients and to the company to conform with these standards.” The alternatives, such as a feeder with a second, remote panel, are worth exploring. As Lloyd says, “there’s lots of options that you can look at…”
Why does any of this matter to the owner?
Unverified assemblies rarely fail on commissioning day. They fail years later, usually through heat, and by then nobody connects the failure to the design decision that caused it. The safety risk and the operational cost land on the owner, who carries an ongoing legal duty under the OHS Act to keep the equipment safe.
Lloyd describes the pattern he sees most: “Those breakers are now getting a lot smaller. You can fit them into a smaller compartment, but the heat losses are the same and it relies on the steel surface to dissipate the heat out of the cubicle into the atmosphere.”
When that arrangement hasn’t been verified, the panel runs hot. “The failures we see are over temperature, panels are getting too hot, there’s fire, and of course it’s not immediate, it’s a few years down the line,” he says. “So nobody really goes back and says, look now that’s the root cause of that problem because the assembler put in the wrong size cubicle.”
The law splits the duty. Section 10 of the OHS Act requires anyone who designs, manufactures, imports, sells or supplies an article for use at work to ensure, as far as reasonably practicable, that it is safe and complies with prescribed requirements. Section 8 requires the employer to provide and maintain a safe working environment, as far as reasonably practicable. The owner’s duty continues for as long as the panel is in service.
What should you ask for at tender stage?
Ask for proof of compliance with the bid, not a promise of compliance after award. Lloyd notes that many industrial clients now do this, so adjudicators can check during evaluation whether a bidder can back its claim. Put these four questions to every bidder, in writing, before any order is placed.
- Whose design is this, and who verified it? Name the design being offered and its original manufacturer.
- What is the evidence? Provide the design verification records and the method used for each characteristic.
- Does our requirement fit inside the verified design? If not, what deviates, and who will verify the change?
- Do you make your own enclosures? Lloyd puts it simply: “Are you reliant on somebody else to provide you the steelwork?” The answer affects control of the design and of delivery lead times.
How do you check the design hasn’t drifted from what was verified?
Once the design is approved, ask in writing: has anything deviated from the verified design, and who verified it? Ask for a schedule of deviations, or a written statement that there are none. Small physical changes, such as an extra cut-out or a re-routed cable way, can change heat dissipation or structural strength.
A general arrangement drawing shows what the panel looks like. It does not show whether what is inside has been verified. That evidence sits in the design verification records and the deviation schedule.
What should you check at the factory acceptance test?
The factory acceptance test (FAT) is your last chance to confirm, before the panel leaves the factory, that what was designed and documented is what was built. Go with the approved drawings and the deviation schedule from the design stage. Ask to see the evidence behind each rating, not only the finished panel.
| Check at FAT | What to look for |
|---|---|
| Declaration of conformity | References SANS 61439 and SANS 1973, and the ratings you ordered: rated current, short-circuit rating, IP rating |
| Routine verification records | For this specific unit, not a generic certificate for the design family |
| Nameplate | Ratings match the specification and the declaration |
| Data pack | Design verification evidence, routine test report, general arrangement drawings, wiring diagrams |
| Supporting calculations | Available on request, for example busbar temperature |
| Deviation schedule | Closed out against the design stage |
Lloyd’s view is that the onus sits with the builder at FAT: “Does this panel comply? Yes, can I have a declaration of conformance? Yes, sir, that forms part of your data pack. Here’s all the test reports.”
On calculations, he is specific: “What temperature are my busbars going to run at? You must be able to produce the report or the calculation to show that, based on your verified tested sample panel, that the coppers are going to run at a certain temperature.”
What is the difference between a declaration of conformity and a certificate of compliance?
A declaration of conformity (DoC) is issued by the assembly manufacturer and covers the panel against SANS 61439 and SANS 1973. A certificate of compliance (CoC) is issued by a registered person under the Electrical Installation Regulations, 2009, and covers the electrical installation the panel is connected into. One does not prove the other.
| Declaration of conformity | Certificate of compliance | |
|---|---|---|
| Covers | The low-voltage assembly | The electrical installation |
| Issued by | The assembly manufacturer | A registered person under the Electrical Installation Regulations, 2009 |
| Measured against | SANS 61439 and SANS 1973 | SANS 10142-1 |
| When | At handover from the factory | After installation and testing on site |
The contractor issuing the CoC does not re-verify the panel. “So the electrical contractor sees that as a black box,” Lloyd says. “All they need to do their COC is a declaration of conformance to put with their COC pack.” That is why the declaration must be backed by real verification evidence.
Do existing panels have to comply with SANS 61439?
No. A panel built to the standard in force at the time does not have to be replaced each time the standard changes. The owner’s duty under the OHS Act to keep it safe does not lapse, though. A condition survey is the starting point for deciding what to maintain, retrofit or replace.
“You can’t expect the client to change their panel every time there’s a change in the standards,” Lloyd says.
In my experience, LV panels are built for a design life of 25 to 30 years and are often kept in service longer. A retrofit can bring individual compartments up to current practice. Whether a retrofitted panel as a whole can then carry a declaration of conformity to SANS 61439 depends on the scope of the work and who holds the original design.
What is the one question to ask your supplier?
Ask: “Has anything deviated from the verified design, and who verified it?” A specific answer backed by documents means the builder can prove compliance. A vague answer means you are relying on trust. Ask for proof, not labels. A category name or a component certificate is not evidence that your assembly was verified.
Proof matters because test claims are not always what they seem. In Lloyd’s experience, some enclosure kits are sold with a test report that covers only the busbars, and some builders piece together a compliance story from separate tests done at different times. It is the same gap the old STA category left open.
The evidence a buyer needs covers the complete panel as it was built and equipped, not one part of it. In Lloyd’s words, the client must know that “the entire assembly with everything equipped as it is, tested at the factory, it conforms to the standards.”
How Panel Technique approaches this
We hold both roles. PT1000 is our own design, design-verified by test to SANS/IEC 61439 and tested under internal arcing fault conditions in accordance with IEC/TR 61641, and we build and equip it in our own factory in Westmead, Durban, where we have built low-voltage assemblies since 1989. When a site needs a non-standard layout or a preferred component brand, we can verify the change against our own tested reference design. Lloyd calls it “holding both hats.” Clients are welcome at every FAT.
Summary: what should a buyer ask to get a genuinely SANS 61439 compliant panel?
Ask eight questions across three stages, and get every answer in writing. At tender, establish whose design it is and what proves it. At design, confirm nothing has drifted from the verified design. At the factory acceptance test, check that the panel in front of you matches the paperwork. If the supplier cannot answer any of them with documents, treat the panel as unverified.
| Stage | Question to ask | A good answer includes |
|---|---|---|
| Tender | Whose design is this, and who verified it? | The named design and its original manufacturer |
| Tender | What is the evidence? | Design verification records and the method used for each characteristic |
| Tender | Does our requirement fit inside the verified design? | A clear yes, or a list of deviations and who will verify them |
| Tender | Do you make your own enclosures? | Who controls the steelwork, the design and the lead time |
| Design | Has anything deviated from the verified design, and who verified it? | A deviation schedule, or a written statement that there are none |
| Design | If you swapped a device brand, how did you prove it is equal or better? | Power loss, temperature rise and short-circuit data for the substitute |
| FAT | Does the declaration of conformity match what we ordered? | SANS 61439 and SANS 1973 referenced, with our rated current, short-circuit rating and IP rating |
| FAT | Where are the routine verification records for this unit? | Test records for this specific panel, not the design family |
Keep the declaration of conformity with the data pack. The electrical contractor will need it to issue the certificate of compliance for the installation.
Frequently asked questions
Is SANS 61439 mandatory in South Africa?
Yes, in effect. Section 10 of the OHS Act requires articles to comply with prescribed requirements, and SANS 10142-1 (Table 4.1) requires installed low-voltage assemblies to carry evidence of compliance with SANS 1973, which incorporates SANS 61439.
Are TTA, PTTA and STA still valid categories?
No. Those categories belong to the superseded SANS 60439 and SANS 1473 standards. Testing is still used, but as one of the methods of design verification under SANS 61439.
Who issues the declaration of conformity?
The assembly manufacturer: the company that built your specific panel and carried out its routine verification.
Can I specify my plant’s preferred breaker brand?
Yes, if the builder verifies the substitute in that specific arrangement, for temperature rise and short-circuit performance. Whoever makes the change takes responsibility for verifying it.
Does a certificate of compliance prove my panel complies with SANS 61439?
No. A CoC covers the installation. Panel compliance is shown by the assembly manufacturer’s declaration of conformity and its supporting verification evidence.
What is SANS 1973-1?
The South African front-end standard read together with SANS 61439 for low-voltage assemblies. It captures the SANS 61439-1 requirements and adapts them for local conditions. SANS 1973-3 covers assemblies rated at or below 10 kA.
Sources
- Electrical Installation Regulations, 2009: nioh.ac.za (PDF)
- Occupational Health and Safety Act 85 of 1993, sections 8 and 10: acts.co.za
- IEC 61439 series: webstore.iec.ch
- “IEC 61439: who is responsible for proving compliance”, Sparks Electrical News: crown.co.za
- “Integration of devices and components”, IET Wiring Matters, March 2025: electrical.theiet.org
- BEAMA Guide to Verification of LV power switchgear and controlgear assemblies (BS EN IEC 61439-2): beama.org.uk (PDF)
- NHP technical note on device substitution under AS/NZS 61439-1: nhp.com.au
- Eskom LV switchgear and controlgear assemblies standard 240-56227516, citing SANS 1973-1 and SANS 10142-1 Table 4.1: etenders.gov.za
- Lloyd Barends, Summary of LV Standards (internal research notes, 16 September 2026)
- SANS 61439, SANS 1973 and SANS 10142-1: SABS webstore
