Start your own trade business and somewhere in the paperwork, without anyone telling you directly, you become something the law has a specific name for. Not "sole trader." Not "self-employed." A PCBU - a person conducting a business or undertaking. And a PCBU has legal duties that exist from day one, whether you're a one-person operation or running a crew of twelve.
Most tradies have never heard the acronym. Fewer could tell you what it actually requires of them. Here's the plain version.
The short answer
Running your own trade business makes you a PCBU under the WHS Act, with a primary duty of care that applies from your first day of trading - including to yourself, if you work alone. That duty extends to subcontractors, apprentices, and anyone your work could reasonably affect, not just people you formally employ. It can't be transferred away by hiring someone else to do the risky part. Breaching it carries real penalties, and the more serious categories can mean personal fines well into six figures.
What "PCBU" actually means, in plain terms
Under the model WHS Act, a PCBU is essentially anyone running a business, in any structure - sole trader, partnership, company. If you invoice clients under your own ABN and run the show, you're a PCBU. The term deliberately doesn't care whether you've got one person or fifty on the books.
This matters because a lot of tradies mentally file WHS obligations under "stuff that applies once I have staff." It doesn't work that way. Section 19(5) of the WHS Act specifically requires a self-employed person to ensure, so far as reasonably practicable, their own health and safety while at work - the duty exists even if you're the only person on the job.
The primary duty of care - who it actually covers
Section 19 sets out the primary duty, and it's broader than most people assume. A PCBU must ensure, so far as is reasonably practicable, the health and safety of:
- Workers engaged directly - employees, apprentices, people you employ.
- Workers "engaged or caused to be engaged" by you - which includes subcontractors and labour hire workers you bring onto a job, even though you're not their formal employer.
- Yourself, if you're self-employed - your own physical and psychological health and safety while at work.
- Other people whose health and safety could be put at risk by the work - which reaches beyond the job site to include, for instance, a member of the public walking past a poorly secured excavation.
That subcontractor point is worth sitting with. A lot of tradies assume that once someone is engaged as an independent subcontractor rather than an employee, the safety obligation somehow shifts entirely onto them. It doesn't. If you bring a subcontractor onto a site you're managing, your primary duty of care extends to them too.
What "so far as reasonably practicable" actually means
This phrase does a lot of legal work, and it's worth understanding properly rather than treating it as vague legal filler.
It doesn't mean "eliminate every possible risk, no matter the cost." It means weighing up:
- How likely the hazard is to actually occur.
- How severe the harm would be if it did.
- What you knew, or reasonably should have known, about the hazard.
- What it would cost in time, effort, and money to eliminate or reduce the risk, weighed against how much risk that action actually removes.
In practice, this is judged after the fact against what you actually did, not what you meant to do or would have done given more time. This is exactly why documentation matters - a SWMS, a site induction, a toolbox talk, a photo of the controls you put in place. If something goes wrong, "I was being careful" is a much weaker position than "here's the SWMS I completed before we started, and here's what it says we did about this exact hazard."
The duty can't be handed off
This is the part that catches people out most. Hiring a subcontractor to do the dangerous part of a job doesn't transfer your primary duty of care to them - it sits alongside theirs. Multiple people can hold a concurrent duty for the same work, and none of them can offload it entirely onto someone else just by structuring the arrangement a certain way.
Practically, this means: if you engage a subcontractor for height work and they turn up without proper fall protection, you having "just hired them to do it" is not a complete defence. If you were in a position to identify that risk and do something about it - check their gear, confirm their training, require a SWMS before they started - your own duty was still active the whole time.
What breaching it actually costs
WHS offences are split into three categories based on seriousness, and the penalties scale accordingly:
| Category | What it involves | Roughly what it costs |
|---|---|---|
| Category 3 | Failing to comply with a duty - no need to prove exposure to risk of harm | Can still run into tens of thousands of dollars for an individual, depending on the state |
| Category 2 | A duty breach that exposes someone to risk of death or serious injury | Substantially higher - can run into the hundreds of thousands for an individual |
| Category 1 | Reckless or grossly negligent conduct, exposing someone to risk of death or serious injury | The most severe - can include imprisonment as well as very large fines |
Exact figures vary by state and territory legislation, and the model penalty amounts are periodically updated - worth checking your specific state regulator's current published figures rather than relying on a number that might already be a year out of date by the time you read it. What matters more than the specific dollar figure: none of this requires someone to actually be hurt. A Category 3 offence can apply purely for failing to have appropriate systems in place, regardless of outcome.
What this looks like day to day for a solo tradie
None of this needs to feel abstract or overwhelming. In practice, meeting your PCBU duty as a solo or small operator mostly comes down to:
- Using the right equipment for the job, maintained properly, not the quickest thing lying in the van.
- Having a genuine safe system of work for anything high-risk - documented where the law requires it, like a SWMS for high-risk construction work.
- Checking a subcontractor's competency and gear before they start on a site you're managing, not just assuming they've got it sorted.
- Managing the site itself - securing hazards from the public, not just your own crew.
- Keeping a record of what you did to manage risk, so if a question ever comes up later, there's something more substantial than memory to point to.
For anyone working at height, near live electrical, or doing other high-risk construction work specifically, the guides on working at heights requirements and High Risk Work Licences cover the detailed obligations layered on top of the general PCBU duty for that specific kind of work.
Frequently asked questions
Am I a PCBU if I'm just a sole trader with no employees?
Yes. Running your own trade business, even solo, makes you a PCBU under the WHS Act. Section 19(5) specifically requires a self-employed person to ensure, so far as reasonably practicable, their own health and safety while at work. Working alone doesn't remove the duty, it just narrows who else you owe it to.
Do I owe WHS duties to subcontractors I hire for a job?
Yes. The primary duty of care extends to workers engaged or caused to be engaged by you, which includes subcontractors and labour hire workers, not just direct employees. Bringing a subcontractor onto a site you're managing means you owe them the same duty to manage foreseeable risks - the contracting arrangement doesn't reduce the obligation.
What does "reasonably practicable" actually mean in WHS law?
It's the legal test for how far your duty goes - doing what's reasonably practicable to eliminate or minimise risk, not achieving impossible zero risk. It weighs the likelihood of a hazard, the severity of harm, what you knew or should have known, and the cost of fixing it against the risk removed. It's assessed against what you actually did, which is why documentation like SWMS and site records matters.
What happens if I breach my PCBU duty as a sole trader?
Penalties scale by category of seriousness. A Category 3 offence - simply failing to meet a duty, no injury required - can still mean fines in the tens of thousands for an individual. Category 1 and 2 offences, involving exposure to risk of death or serious injury, carry far more severe penalties including possible imprisonment for the worst cases. The primary duty also can't be transferred away by hiring a subcontractor to take on the risk instead.