NRS 097 dual-supply labelling for home solar in South Africa

Answer first: Dual-supply labelling is not decorative stickers. It is a utility-interface safety requirement so municipal workers and private electricians know your DB can still be live from the inverter/battery when the street is dead. Fit the NRS wording (or clear equivalent), mark every isolation point, and put related labels at the meter and, where required, feeder/substation cues during commissioning.

What NRS 097-2-1:2024 actually says

Section 5.10 (Labelling) of NRS 097-2-1:2024 requires:

• A label on the distribution board stating: “WARNING: ON-SITE EMBEDDED GENERATION. DO NOT WORK ON THIS EQUIPMENT UNTIL IT IS ISOLATED FROM BOTH MAINS AND ON-SITE GENERATION SUPPLIES.” (or similar warning).
• Disconnection points for all supplies indicated.
• Permanent label, lettering height at least 8 mm.
• Compliance with SABS 1186-1.

Primary PDF: NRS 097-2-1:2024 via sseg.org.za. Related explainer: what is NRS 097?, approved inverters.

Why “both supplies” matters during load shedding

Hybrids can form a local AC island on the essentials board while the utility is off. A worker who only opens the municipal isolator can still meet live conductors fed from the battery inverter. The label forces a two-source isolation habit. Anti-islanding protects the grid side; labelling protects humans on your property.

Where labels usually go

1. Main DB / SSEG DB — the NRS dual-supply warning, plus clear “SSEG infeed” / point-of-connection markers.
2. Metering point / point of supply — commissioning checklists used by municipalities expect SSEG indication here so field staff see it before opening equipment.
3. Single-line diagram (SLD) — laminated or sleeved near the DB showing interconnection and isolation points (SSEG portal commissioning guidance).
4. Inverter disconnects — AC and DC isolators labelled so a non-specialist can find them in an emergency.

SSEG.org.za commissioning material asks inspectors to verify DB labels, SLD, and preferably feeder/transformer indication on the network side where applicable.

Commissioning and municipal sign-off

Knysna-style and national template commissioning reports explicitly tick: safety labels fitted according to NRS 097-2-1 on the distribution board and metering point; anti-islanding tests; CoC attached. Cape Town’s process leans on ECSA professional sign-off and document packs — labels still form part of NRS compliance the professional is certifying. See municipal SSEG steps, CoC, inspector tips.

Practical label hygiene

• Use engraved/traffolyte or other permanent SABS 1186-1-compliant labels — not masking tape markers that fade in a garage.
• 8 mm is a minimum letter height — do not shrink the warning to fit a cute icon strip.
• Update labels when you add a second inverter, a generator ATS, or move the SSEG connection point.
• Photograph labels for your warranty and insurance file.

Generators, ATS and “extra” sources

If a generator can also feed the board through a changeover, treat that as another source in the isolation story. Incorrect ATS wiring is a frequent hazard — ATS guide. UPS units that can parallel with the utility are themselves SSEG under NRS definitions when they operate in parallel modes.

Homeowner checklist before you pay the final invoice

1. Read the exact label text on the DB — does it warn about both mains and on-site generation?
2. Can you point to every disconnect the label refers to?
3. Is there an SLD within reach of the DB?
4. Is the meter / point of supply marked for SSEG?
5. Do photos of the labels sit in your handover pack with the CoC?

SA caveats

NRS editions update; metros may publish supplemental labelling notes. This page summarises the 2024 labelling clause for education — your ECSA professional and registered electrician own compliance on site.

Worked label placement on a typical hybrid home

Main DB in the garage: NRS dual-supply warning at eye height on the door or adjacent fascia. Essentials sub-board: smaller “fed from hybrid inverter” marker plus isolator tag. Meter box on the street boundary: SSEG present label so utility staff see it before opening. Inverter wall: AC isolator and DC isolator tagged with ON/OFF direction. Laminated SLD in a plastic sleeve inside the DB door — commissioning checklists look for it.

Common fails that bounce commissioning

• Warning text that only mentions “solar” without “both mains and on-site generation.”
• Lettering under 8 mm or a paper printout behind Sellotape.
• No indication of where to isolate the inverter/battery supply.
• Labels fitted for the first install, then a second battery inverter added with no update.
• Generator ATS added later with no change to the isolation story.

Fix these before the ECSA professional arrives — inspector tips.

Rentals and Airbnbs

If tenants or cleaners can open the DB, the label is for them too. Include a one-page shutdown sequence in the house folder. Body corporates sometimes specify label colours — comply, but do not drop the NRS wording to satisfy an aesthetic rule.

How this ties to earthing and SPD

Labelling does not replace correct earthing/bonding or surge protection — it only warns humans about dual energisation. Still verify bonding and SPD as separate checklist items — earthing, SPD. A pretty label on an unsafe board still fails a competent inspection.

Quick questions

Is a handwritten sticker enough?

No. NRS wants a permanent label meeting SABS 1186-1 with ≥8 mm lettering.

Do zero-export hybrids still need the label?

Yes. NRS treats parallel-capable plant as SSEG even when software blocks export.

Where can I read the rule myself?

NRS 097-2-1:2024 section 5.10 — PDF hosted on sseg.org.za.

Where the stickers go (and what happens when they don’t)

Dual-supply and embedded-generation labels exist so the next electrician — or the firefighter — knows energy can still be present when the municipal feed is dead. Typical placements: main DB outer door, inverter AC isolator, battery enclosure, and any changeover / ATS enclosure. Use durable engraved or municipal-accepted labels, not masking tape markers that fade in a year.

Missing labels are a common CoC bounce and a common SSEG photo reject. They also create real safety risk during load shedding when owners assume “grid off = house dead” while the hybrid is islanding essentials. Budget thirty minutes at handover for a label walk-through with the homeowner present.

If you later add an EV wallbox or a second inverter, update the diagram and labels in the same visit. Orphan circuits without notes are how interlocks get defeated. Tie this to what NRS 097 is and inspector tips.

Changeover switches and generator ties

When a hybrid, municipal supply and a generator all meet at one DB, labelling alone is not enough — the mechanical or electrical interlock must match the drawing. Inspectors look for break-before-make behaviour and for notices that name which handle does what. A beautiful sticker on a dangerous changeover still fails the safety intent.

Photograph the interlock position in both grid and island modes for the project album. Future electricians inherit your photos when WhatsApp threads disappear. Pair with ATS guidance.

Sources

• NRS 097-2-1:2024 (labelling §5.10)
• SSEG.org.za — inspections, commissioning and sign-off
• Example municipal commissioning report (labels tick-box)