A circuit breaker lockout is a small physical device that holds a breaker in the off position so it cannot be switched back on. On any site with multiple workers and multiple trades, locking out the breaker is imperative. As a result, it stops a circuit being accidentally re-energised while someone is still working on it. This guide covers the main types of circuit breaker lockout devices and what each one suits.
How a Circuit Breaker Lockout Works
A circuit breaker lockout works as a physical barrier. In practice, it clamps onto the breaker and blocks the switch, so the circuit cannot be turned on while the device is fitted.
The device always works alongside two other items:
- A padlock – secures the device so only the keyholder can remove it.
- An information tag – states why the circuit is locked out and who to see on site with any questions.
This practice sits under AS/NZS 4836, the Australian standard for safe working on or near low-voltage electrical installations. Manufacturers also build quality lockout devices to comply with AS 4836 and AS 4024.1603.
Types of Circuit Breaker Lockout Devices
Breakers vary widely, so we group lockout devices by the style of breaker they suit. In short, below are the four main groups.
Mini
Mini lockouts suit small ISO/DIN circuit breakers — the common single-pole breakers found in most switchboards. They clamp onto the breaker body and hold the toggle in place.
- UCL1 – our most popular mini device; suits ISO/DIN breakers, takes a padlock shank up to 7.5mm, fits with a slotted insulated screwdriver.
- UCL2 – a mini device for ISO/DIN breakers with a different toggle profile.
- UCL4 – sized for wider mini breakers the UCL1 won’t grip.
- UCL7 – for larger mini breakers again beyond the smaller devices.
Euro-Style Breakers
Euro-style breakers use a pin or bar arrangement rather than a standard toggle. These lockouts match that mechanism.
- Pin In – for breakers where the tie-bar pin sits in.
- Pin Out – for breakers where the pin sits out.
- Pin Out Wide – a wider version for larger pin-out breakers.
- T-Bar – for breakers with a T-bar style actuator.
Industrial Applications
Larger breakers and moulded-case units need heavier devices. This group covers industrial switchboards and higher-current gear.
- UCL5 – for larger breakers than the mini range covers.
- Tight Grip – grips breakers that lack a clear clamping point.
- MCCB – for moulded-case circuit breakers.
- Blocking Bar – blocks a bank of breakers or a wider actuator.
- Snap On – clips on quickly where a screwdriver fit is not practical.
Specific Applications
Some breaker brands need a purpose-made device. These are niche but essential where the standard groups will not fit.
- Schneider – shaped for various Schneider breakers. The maker designs each version for that particular breaker.
Where a Circuit Breaker Lockout Fits in a Lockout Kit
A single device rarely covers a whole site. For example, the best approach is to start with a generic lockout kit that includes a range of the common breaker devices, then add specific items – like a Schneider or MCCB lockout – as jobs require. For sites with unusual gear, you can request a custom-built kit.
A kit matters because the circuit breaker lockout is only one part of the job. To complete the lockout procedure, you also need:
- A padlock – to secure each device.
- An information tag – a “do not operate” tag explaining the lockout.
- A hasp – lets multiple workers each apply their own padlock to one point, so the circuit stays locked until every worker has finished.
Our personal lockout kit with belt bag bundles these together – circuit breaker lockouts, padlocks, a screwdriver, a hasp and do-not-operate tags – so a worker can carry the full set to any site. For the wider process, see our guide to lockout tagout for electrical work.
Conclusion
There are various types of circuit breaker lockout devices on the market. Some suit multiple styles of breaker, while others have a very specific niche application. Therefore, the right choice is the one that fits your breaker, takes your padlock, and complies with AS 4836. Choose the correct circuit breaker lockout to keep every worker on site safe at all times.
Browse the full Volt Safety circuit breaker lockout range at:
https://voltsafety.com.au/product-category/lockout