Best MCB Lockout Devices for Safe Isolation: 2025 Expert Review
Oli at OR Electrics
18th Edition Electrician & Owner
Safe isolation is the most critical procedure an electrician performs. Whether I'm working on a consumer unit upgrade in a Headingley student let or fixing a fault in an Armley terrace, the rule is simple: determine, lock off, verify. But 'locking off' can be a headache if your lockout device doesn't fit the breaker.
The market is flooded with 'universal' devices, but anyone who has wrestled with an old Wylex or a stubborn Hager breaker knows that universal is rarely true. In Leeds, we see such a variety of electrical installations—from 1970s rewirable fuses to modern RCBO boards—that having a versatile lockout kit is non-negotiable.
In this review, I'm looking at three MCB lockout options that help us adhere to the Electricity at Work Regulations 1989. I'll cover a budget pin-style set, a high-quality screw-lock set for your main toolkit, and a problem-solving solution for those awkward breakers that refuse to be isolated.
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Specs vs. The Real World
The Spec: "Universal Compatibility"
"One lockout device fits every single Miniature Circuit Breaker (MCB) and RCBO on the market."
Breaker toggle shapes vary wildly between brands (Schneider, MK, Hager). 'Pin' styles require locator holes, which many older breakers lack. You need a mix of pin and screw-clamp types.
The Spec: "Durability"
"Plastic devices handle the rigours of daily industrial use."
Cheap nylon threads strip easily if you overtighten the grub screw. Metal-reinforced threads or high-quality glass-filled nylon are essential for longevity.
My Top 3 Recommendations
Three options to cover different needs and budgets
10PCS Master Miniature Circuit Breaker (MCB) Lockout Pins 8mm Lock Off Kit
TIANXUAN
This 10-piece kit uses the 'pin-out' mechanism, designed for breakers with two locator holes on the toggle. At £7.49, it's an incredibly cost-effective way to stock up a lockout station or a large team kit. While not truly universal, they are perfect for modern boards.
The Good
- Excellent price per unit
- Aluminium build offers decent arc flash resistance
- Twist-lock mechanism is tool-free
The Bad
- Only works on breakers with 'pin-out' locator holes
- Twist mechanism can feel fiddly with gloves on
Installer Tip:
Before you rely on this, visually inspect the breaker toggle. Many older MCBs found in Leeds rentals don't have the pin holes. If the holes are there, ensure the pins click fully home before attaching your padlock.
Priced at £7.49 at the time of writing
Check Price on AmazonQWORK® 8PCS Miniature Circuit Breaker (MCB) Lockout with Screw
QWORK
When the pin-style locks fail, the screw-clamp is your best friend. This 8-piece set from QWORK clamps directly onto the breaker toggle using a thumb screw (or screwdriver slot). It's more versatile than the pin type and feels robust enough for daily use.
The Good
- Fits MCBs without locator holes (clamping action)
- Glass-filled nylon is tough and durable
- Can be tightened by hand or screwdriver for extra security
The Bad
- Slightly bulkier on the board than pin types
- Requires care not to overtighten and crush plastic toggles
Installer Tip:
I keep these in the van for older boards or brands like Merlin Gerin where pin spacing can be odd. The 'screw' action bites into the plastic toggle—give it a firm wiggle to check it won't slide off before you hang your tag.
Priced at £14.98 at the time of writing
Check Price on AmazonQWORK 4PCS Miniature Circuit Breaker (MCB) Lockout with Screw
QWORK
This is the smaller 4-pack version of the clamp-style lock. I've categorised this as the problem-solver because having just a few of these in your pocket test kit saves you walking back to the van. They tackle the tricky breakers that standard pin locks can't grip.
The Good
- Solves the 'no pin hole' problem on older breakers
- Compact enough to keep in a pocket or pouch
- Simple, reliable screw mechanism
The Bad
- More expensive per unit than the bulk packs
- Thumb screw can be stiff initially
Installer Tip:
Use these for specific isolation tasks where you encounter a rogue breaker type in a mixed consumer unit. The screw mechanism allows you to securely lock off a single circuit even if the adjacent breakers are crowded.
Priced at £9.99 at the time of writing
Check Price on AmazonFrequently Asked Questions
Why do I need different types of MCB lockout devices?
Can I just use electrical tape to mark a breaker as off?
Do I need a padlock for these devices?
Are these devices suitable for commercial 3-phase options?
I'm a landlord in Leeds, do I need these?
How do I upgrade my old unit to make isolation easier?
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