Why this matters more than tagging
Here is a sentence from WorkSafe's own test-and-tag guidance that almost nobody quotes, because it undercuts the product being sold on the same page:
"And remember, whether tested and tagged or not, electrical equipment still needs to be RCD-protected in certain circumstances, such as outside in the damp."
Read that alongside the other thing WorkSafe says on the same page — that testing and tagging is not mandatory — and the priority becomes clear.
Testing is voluntary and tells you an appliance was sound on one day. RCD protection is required and works on all the other days. If a business could only do one, it should not be the tagging.
We say that knowing it argues against the service most people call us about first.
Where the requirement comes from
The chain is short and worth knowing, because it explains why the answer to "what exactly is required" keeps moving.
The Electricity (Safety) Regulations 2010 are the law. They set core safety requirements and, critically, they cite standards — meaning the standard's content becomes the practical requirement for work carried out under the regulations.
AS/NZS 3000 — the Wiring Rules — is the cited standard for the design and construction of electrical installations. It is where the detailed requirements for where RCDs go actually live.
AS/NZS 3012 is cited for construction and demolition sites, and AS/NZS 3001.1 and 3001.2 for connectable installations such as relocatable buildings and caravans.
So "is an RCD required here" is answered by the cited standard for that type of installation, not by a single clause in the regulations. This is also why the November 2025 amendment matters so much: it changed which versions are cited.
What the regulations set
The regulations themselves deal with performance rather than placement. Regulation 24 addresses when an RCD is electrically unsafe.
In broad terms, an RCD used to protect against electric shock — whether installed as part of an installation or a portable RCD — is expected to have a rated residual current not exceeding 30 mA, and to interrupt the current in all live conductors within 300 milliseconds at its rated residual current, or within 40 milliseconds at five times that current. Where an RCD is protecting children from direct contact with electricity, the figure is 10 mA.
Those numbers are the reason measured trip-time testing exists. An RCD that trips, but takes 400 milliseconds to do it, meets nobody's definition of working — and there is no way to know without measuring. See push-button vs trip-time testing.
This is a plain-English summary of the direction of regulation 24, not a reproduction of it. Read the regulation itself if the detail matters to you — it is short, free and linked in the sources below.
Where RCDs are required in practice
Rather than paraphrase the Wiring Rules — which are copyrighted and which your electrician should be working from directly — here is where the question actually arises on a commercial site, and what to expect.
Socket outlets in modern installations. Broadly, general-purpose socket outlets in installations designed to current versions of AS/NZS 3000 are required to have RCD protection. Older installations may legitimately not.
Anything outdoors or exposed to weather. This is WorkSafe's own example and it is the highest-risk case in most workplaces: yards, loading docks, external power for cleaning or maintenance, temporary event power.
Wet and wash-down areas. Commercial kitchens, laundries, food processing, wash bays, plant rooms with hose-down cleaning.
Construction and demolition sites. All supply RCD-protected, under AS/NZS 3012. See test and tag on construction sites.
Where you are supplying power to people you do not control. Hired equipment, contractors working from your outlets, public-facing outlets. If you cannot supervise the equipment being plugged in, the RCD is doing the supervising.
Medical and specialised installations, which have their own cited standards.
The practical rule of thumb: the further the equipment is from a dry office and a competent user, the more certain you should be that there is an RCD in the path.
Existing installations are not condemned
This is the question every building owner asks next, and the answer is more generous than they expect.
WorkSafe's guidance on the amendment regulations is explicit: the amendment allows current installations to continue to exist and be repaired so long as they are not unsafe, and there is no time limit on this.
So an older building without RCD protection on every circuit is not automatically non-compliant, and nobody is required to rewire it because a standard was updated.
What triggers the new requirements is change. If you are relocating, adding to or altering an existing installation, the parts you change need to comply with the newly cited standard. Only the parts you change — there is no requirement to bring the rest of the installation up with them.
Repairs sit in their own category: the old version of the standard can continue to be used for repair work. If repair work turns into an alteration or addition, that part needs the new standard.
This distinction — repair versus alteration — does real financial work. It is worth having the conversation with your electrician before a job is scoped rather than after, because how the work is defined determines what it drags in with it.
What changes on 12 November 2026
Mark this one. From 12 November 2026, new installation work must comply with the newly cited standards, including AS/NZS 3000:2018 in place of the 2007 edition.
The most consequential change for RCDs is the type requirement. Work under the new citation requires RCDs providing shock protection to be Type A (to IEC 61009.1 or IEC 61008.1), or Type F or Type B (to IEC 62423). Plain Type AC, which is what a great many existing boards contain, is not sufficient for new work.
There is also a new obligation to select and install RCDs compatible with the types of load intended to be used, with consideration given to pulsating and constant DC fault currents and waveform distortion. In a building full of variable speed drives, LED drivers, EV chargers and switch-mode power supplies, that is not a theoretical concern.
The full picture, including what it means for boards you already have, is in RCD types and what changes in November 2026.
What to check on your site
You do not need to be an electrician to work out whether you have a problem worth investigating.
- Walk the outside of the building. Every external socket outlet — is there an RCD in that circuit? If nobody can answer, that is the answer.
- Check the wet areas. Kitchen, laundry, wash bay, plant room.
- Look at the board. Are there RCDs or RCBOs at all, and does anyone know which circuits they cover? A board with no circuit schedule is very common and makes every subsequent question harder.
- Ask when they were last actually tested — measured, not push-button. In most buildings the honest answer is never.
- Ask who presses the test buttons and how often. Usually nobody.
- Check for portable RCDs in use, and whether anyone is testing those. See portable RCDs and PSOAs.
If the answers are uncomfortable, that is normal. RCDs are the most important protective device in the building and the least attended to, precisely because they are silent when they are working and silent when they are not.
Related: how often RCDs should be tested and why an RCD keeps tripping.