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Fail-safe electric door lock

Updated: 16 October 2026

A fail-safe electric door lock locks while it is powered and unlocks when the power is removed. All four 12 V listings in this set say that, so a power cut opens the door. If you needed the door to stay shut when the supply dies, stop here and do not buy them. A stated 60 kg hold is a cupboard figure, not a house lock. The captures are amazon.co.uk on 15 October 2026. The Products Compared editorial team did not test holding force or an escape route. We may earn a commission if you buy through our links. House locks with batteries are on the [electronic door lock comparison](/hub/electronic-surveillance/electronic-door-lock).

A fail-safe electric door lock locks while it is powered and unlocks when the power is removed. All four 12 V listings in this set say that, so a power cut opens the door.

Our top picks

Uoonner Uoonner 12 V bolt kit with Tuya keypad

Best overall

Uoonner Uoonner 12 V bolt kit with Tuya keypad
0.0/10about £50.89
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Kadongli Kadongli 12/24 V fail-safe bolt

Best value

Kadongli Kadongli 12/24 V fail-safe bolt
0.0/10about £23.99
View offer
Fredorlokk Fredorlokk 60 kg magnetic lock

Alternative

Fredorlokk Fredorlokk 60 kg magnetic lock
0.0/10about £21.38
View offer
On this page
  1. 1.These locks open when the power is removed
  2. 2.A stated 60 kg hold is not a house lock
  3. 3.An escape route needs more than a fail-safe bullet
  4. 4.What is in the box, and what fire doors on a title does not prove

These locks open when the power is removed

Fail-safe, on these listings, means power-to-lock. Fail-secure, a lock that stays locked in a power cut, is a different product. None of these four is described as fail-secure. The Uoonner kit, the Kadongli bolt, the Fredorlokk drop bolt, and the Fredorlokk magnet all unlock when power is off. That is useful on a garage or cupboard you want open if the supply fails. It is the wrong behaviour on a final exit that must remain shut. A marketplace bolt does not become a specified access-control door because the title says fail-safe.

A stated 60 kg hold is not a house lock

The Fredorlokk magnet, B0FQCFQ78Z, is about £21.38 with a stated hold of 60 kg at 12 V. There is no review line, and nothing is listed as included. A button or a remote is depending on configuration, which is not a remote in the box. RGL’s guide puts about 60 kg on cabinets, boxes, and machines, and much higher holds on doors people walk through. That is trade context, not a test of this ASIN. The body on the capture is 8 × 4 × 2.5 cm.
Uoonner Uoonner 12 V bolt kit with Tuya keypad

Testsieger

Uoonner Uoonner 12 V bolt kit with Tuya keypad
0.0/10about £50.89
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An escape route needs more than a fail-safe bullet

Approved Document B says an electrically powered lock on an escape route should unlock on the fire alarm, on loss of power or a system error, and from a Type A manual release on the escape side. A fail-safe bullet is only the power-loss part. These listings do not state EN 179, EN 1125, or EN 13637. If the door is a fire door or on an escape route, call a locksmith or an electrician.

What is in the box, and what fire doors on a title does not prove

The Uoonner kit, B0FSS78WW9, is about £50.89 and the only complete kit: an IP68 keypad, ten fobs, an exit button, the bolt, and a 12 V 3 A supply, with Wi-Fi and a Tuya app named. IP68 is the keypad, not the bolt. The listing does not prove it meets the connectable-product rules. The Kadongli, B0H6P2JYH4, is about £23.99 and the lock only, at 12 V or 24 V. Fire-proof has no certificate number. The Fredorlokk bolt, B0FLDG2NJV, is about £29.07 and 4.2 from 6, and both captured reviews are from France. It states 12 V, 1.2 A at start and 120 mA holding. A new mains circuit is notifiable under Approved Document P and is an electrician’s job.

Common questions

What does fail-safe mean on an electric door lock?
On these four listings it means the lock is locked while power is applied and unlocked when power is removed. A power cut therefore opens the door. Fail-secure, which stays locked without power, is a different product, and none of these four is described that way. Buy them only if an open door during a power cut is what you want.
Will this bolt stay locked in a power cut?
No. The Uoonner, Kadongli, and Fredorlokk bolts, and the Fredorlokk magnet, all unlock when power is lost. That is the fail-safe behaviour printed on the listings. If the door must stay shut in a power cut, these are the wrong products. A battery keypad or a mechanical lock is a different mechanism.
Is a 60 kg magnetic lock enough for a front door?
The Fredorlokk magnet states 60 kg, also written as 132 lb, at about £21.38, with no review line. RGL’s guide uses about 60 kg for cabinets, boxes, and machines, and much higher holds for doors people walk through. Treat 60 kg as the figure on this listing and as a cupboard-class hold in that trade guide. It is not a house lock, and it still opens in a power cut.
Can I put one of these on a fire door because the title says fire doors?
No. Kadongli’s fire-proof wording has no certificate number. A title that mentions fire doors is not a doorset test, and it is not EN 179, EN 1125, or EN 13637. Those are system standards these listings do not state. If the door is a fire door, call a locksmith or an electrician rather than fitting a marketplace bolt because the bullet named the door.
What extra release does an escape route need beyond unlocks when power fails?
Approved Document B expects three releases for an electrically powered lock on an escape route: the fire alarm, loss of power or a system error, and a Type A manual release on the side people escape from. Both sides if either direction is an escape. A fail-safe bullet covers only the power-loss part. The alarm interface and the manual release are a designed system, not a DIY extra.
Which of the four listings includes a keypad and a power supply?
Only the Uoonner kit, B0FSS78WW9, at about £50.89. The box includes an IP68 keypad, ten fobs, an exit button, the bolt, and a 12 V 3 A supply. There is no review line. Kadongli is the lock only. The Fredorlokk bolt and magnet do not list a keypad. The keypad’s IP68 rating does not extend to the bolt on this capture.

Related pages

Electronic door lock buying guide

How to fit an electronic door lock

Best electronic door locks

Electronic door locks

Electronic door lock for your uPVC multipoint door

Sources

Public UK sources used for standards and safety context, last checked on 16 October 2026. Prices and star ratings are the amazon.co.uk fields in this category.

  1. Secured by Design: locks and associated hardware (retrieved 16.10.2026)
  2. BSI Knowledge: BS 3621:2017+A1:2024 (retrieved 16.10.2026)
  3. DHF TS 007 cylinder and handle star ratings (retrieved 16.10.2026)
  4. West Yorkshire Police: euro-cylinder advice (retrieved 16.10.2026)
  5. GOV.UK: consumer connectable product security (retrieved 16.10.2026)
  6. GOV.UK: Fire safety, Approved Document B (retrieved 16.10.2026)
  7. Approved Document P (2013), electrical safety (retrieved 16.10.2026)
  8. Consumer Rights Act 2015, section 22 (retrieved 16.10.2026)