A plain-English guide to energy isolation for New Zealand worksites: what lockout/tagout is, where it sits in New Zealand law, the sequence to follow, and which piece of hardware does which job.
We sell the hardware, so treat this as a practical introduction rather than a compliance document. Your isolation procedure is yours to write and yours to own — this page will help you understand what it needs to cover and what to equip your people with.
What lockout/tagout actually is
Lockout/tagout — LOTO — is the practice of isolating every energy source to a machine, locking each isolation point so it cannot be turned back on, and tagging it so everyone knows who isolated it and why. The machine then stays safe for as long as the lock is on.
The broader term is energy isolation, and it is the more accurate one, because electricity is only one of the energies that will hurt someone:
- Electrical — mains supply, control circuits, capacitors that hold a charge after the power is off
- Mechanical — rotating flywheels, belts and drives that coast after shutdown
- Hydraulic and pneumatic — pressure held in lines, accumulators and cylinders after the pump or compressor stops
- Gravity — a raised platform, ram, bucket or counterweight that can fall
- Thermal — steam, hot oil, hot surfaces
- Chemical and process — anything a valve can admit to the space someone is standing in
An isolation is only complete when every one of those that applies has been isolated, locked, and verified at zero energy. A switch in the off position is not an isolation. A switch in the off position with a lock through it, and a test proving there is nothing live downstream, is.
Where this sits in New Zealand law
The governing statute is the Health and Safety at Work Act 2015 (HSWA), with the detail in the Health and Safety at Work (General Risk and Workplace Management) Regulations 2016. Neither one contains a regulation headed “lockout/tagout”. What they require is that a PCBU — a person conducting a business or undertaking — manages risk: eliminate the hazard so far as is reasonably practicable, and where you cannot eliminate it, minimise it.
Isolation is how you do that for maintenance and servicing work. If a machine can start while someone has their hands in it, the risk has not been minimised, and the fact that everyone knew to be careful is not a defence.
WorkSafe New Zealand publishes the practical guidance, and it is worth reading directly rather than second-hand:
- Keeping workers safe with machine lockouts — WorkSafe’s guidance on isolating and de-energising machinery for servicing
- Keeping workers safe when servicing machinery — WorkSafe quick guide (PDF)
WorkSafe also points to the AS/NZS 4024 Safety of Machinery series as good practice, including the part covering prevention of unexpected start-up. Two things WorkSafe is explicit about, and which sites most often get wrong:
- Test the lockout. Prove each energy source is actually isolated and that the machine cannot start, and check nobody is in a position to be hurt if the isolation turns out to be incomplete.
- Train the people doing it. Everyone who applies a lock needs to know the procedure, and supervisors are responsible for it being followed every time — not most of the time.
If you are unsure where your obligations start and stop, WorkSafe’s advisory line is 0800 030 040. Nothing on this page is legal advice, and no product we sell makes a site compliant on its own.
The isolation sequence
Procedures vary by plant, but the shape is consistent. A workable order:
- Plan. Identify every energy source feeding the machine — including the ones that are not obvious, like a control circuit fed from a different board, or a compressed air line that stays charged.
- Notify. Tell the operators and anyone affected before the machine stops.
- Shut down. Use the normal stopping process, not the emergency stop. An e-stop is a safety device, not an isolation point.
- Isolate. Operate each isolating device — breaker, isolator, valve, plug.
- Dissipate stored energy. Bleed pressure, lower or block raised parts, discharge capacitors, let hot surfaces cool.
- Lock. Apply a lockout device and a padlock to every isolation point. Every worker on the job applies their own lock.
- Tag. Attach a tag recording who applied the lock, when, and why.
- Verify. Test for zero energy. Try to start the machine. Prove dead where it is electrical.
- Do the work.
- Restore, in order. Clear tools and people, remove each worker’s own lock, then re-energise and tell the operators.
The one rule underneath all of it: the only person who removes a lock is the person who applied it. The moment a supervisor can cut someone else’s lock off for convenience, the system stops protecting anybody.
One worker, one lock, one key
This is the principle that makes lockout work, and it is why safety padlocks are built differently from the padlock on your garden shed:
- Keyed different as standard. Each worker’s padlock opens only with their key, so nobody else can release their isolation. Our safety padlocks ship keyed different unless you ask otherwise.
- Key retaining. The key cannot be withdrawn while the padlock is open. That stops the most common failure in the field: a lock left hanging on a hasp, looking applied, with the key in someone’s pocket.
- Legible on sight. A safety padlock carries DANGER and DO NOT REMOVE markings and can be engraved or written on, so an isolation can be traced back to a person without asking around.
- Non-conductive where it needs to be. For live electrical work, a padlock with a nylon shackle and body puts no metal near the board at all.
Keying systems are worth deciding deliberately. Keyed different for personal locks; keyed alike where one person routinely locks several points on the same job; master keyed where a supervisor needs a documented override for the case where someone has genuinely left site with their key still in their pocket. Most sites need a mix, and it is far cheaper to plan the scheme once than to re-key later.
Group lockout: when more than one person is working
One isolation point and five workers is the situation that catches people out. Two devices solve it:
- Lockout hasps — the hasp goes on the isolation point and every worker adds their own padlock to it. The hasp cannot open until the last lock comes off. Sizes run from three holes to seven, in steel for strength or nylon where the work is electrical.
- Group lock boxes — for jobs with many isolation points. The isolating locks are applied, their keys go into the box, and the box is then locked shut under every worker’s personal padlock. Nothing can be re-energised until everyone has removed their own lock and released the keys. We stock boxes and stations for 12 and 20 padlocks.
Which device for which energy source
This is where most of the wasted spend happens — devices bought by voltage or by guesswork rather than by the dimension that actually determines fitment.
Electrical
Circuit breaker lockouts are chosen by handle width and toggle type, not by amperage. A pin-out device will not fit a recessed-pin breaker; a device for a 12 mm handle will not close on a 23 mm MCCB handle. Measure the handle. For plug-connected plant, a plug lockout encloses the plug so it cannot be pushed back into a socket — pulling the plug is not an isolation until the plug itself is locked. Emergency-stop lockouts cover 22 mm and 30 mm button heads.
Valves and pipework
Valve lockouts are sized by the valve, not the line: gate valve covers by handwheel diameter, ball valve devices by handle length and width, butterfly valve devices by the lever and latch they have to hold. Adjustable devices earn their keep on sites with mixed valve sizes.
Pneumatic, gas and hydraulic
Pneumatic and air-source lockouts hold quick-disconnect couplings and air valves so a line cannot be reconnected, and gas cylinder lockouts clamp the cylinder valve shut. Stored pressure will injure someone as readily as a live circuit, and it does not announce itself.
The awkward ones
When no rigid device fits — a gate, an odd-shaped handle, several points at once — a cable lockout threads through and locks back into its own body. It is the answer to the isolation points that defeat everything else.
Tags are not optional extras
The lock stops the machine. The tag is the record: who isolated it, when, why, and who to talk to. Without it, an isolation that runs across a shift change becomes a mystery lock that somebody will eventually be tempted to remove. Write-on PVC tags survive weather, oil and washdown where a card tag will not last a week.
Five mistakes worth designing out
- Using the emergency stop as an isolation point. An e-stop removes the command to run. It does not remove the energy.
- Isolating one pole of a ganged breaker. If the handles are linked, the device has to hold all of them.
- One lock shared by a crew. If the lock is not personal, it protects nobody in particular.
- No verification step. Isolating and assuming is how people get hurt by the circuit they thought they had killed.
- Padlocks that outlive their labels. A lock nobody can trace to a person is a lock somebody will cut off.
Where to start
If you are setting up from scratch, a pre-assembled kit covers a technician’s first day and tells you what you actually reach for; a lockout station makes the state of every lock visible in the work area. If you are extending an existing system, the thing to get right is the keying scheme — talk to us before you order and we will work it through with you.
Every product in the range, with the sizes and fitment details you need to specify the right one, is in The Catalogue of Energy Isolation Hardware — free as a PDF or a printed copy.
Everything is held in stock in New Zealand and dispatched from Auckland.