What Are Relockers?
Posted by Jim Noort on 26th Sep 2025
What Are Relockers?
A closer look at the hidden security features that protect your safe from attack
When choosing a safe, most people focus on thickness of steel, fire rating, or locking mechanism. But one of the most important—and often overlooked—features is the relocker. A relocker is a secondary device designed to keep a safe locked even if the main lock is tampered with or destroyed. In many cases, relockers are the reason criminals give up on a break-in attempt.
What Is the Purpose of a Relocker?
The purpose of a relocker is simple: provide backup security. If a burglar drills, punches, or melts the main lock, the relocker activates automatically and drives additional bolts or bars into the door, preventing it from being opened. Unlike the main lock, relockers can’t be reset without skilled manipulation from a safe technician, making them a powerful deterrent.
Types of Relockers
There are several types of relockers, each engineered to respond differently to forced entry attempts:
1. Mechanical Relockers
These are spring-loaded devices that trigger when the safe lock body is physically attacked or removed. Once activated, the relocker bolt engages into the frame or door, keeping the safe sealed until a locksmith resets it.
2. Glass Relockers
A glass plate is mounted behind the lock or across critical areas of the door. If a burglar drills into the safe and shatters the glass, attached cables or wires release multiple bolts into locking positions. Glass relockers are highly effective because they’re unpredictable and difficult to bypass.
3. Thermal Relockers
These activate when extreme heat is applied—such as from a torch. A fusible link or material melts under high temperature, releasing the relocker and adding extra bolts to secure the safe.
4. Combination Systems
Many high-security safes combine two or more relocker types (e.g., mechanical and glass) for layered protection. This makes them far more resilient against both brute force and sophisticated attacks.
How Do Relockers Work in Practice?
During an attack, relockers act as hidden guardians. For example:
- A burglar drills into the lock → a glass relocker shatters and fires extra bolts.
- A thief pries off the lock body → a spring-loaded mechanical relocker snaps into place.
- A torch is applied → thermal relockers melt and engage new locking points.
In each case, the criminal is met with an unexpected barrier, often requiring hours of extra effort—time most burglars don’t have.
Why Relockers Matter
A safe without a relocker is vulnerable. Even the thickest steel door can be compromised if the lock is bypassed. Relockers add a critical layer of protection, ensuring that even under direct attack, your valuables remain secure. That’s why high-quality safes, particularly those rated for cash or firearms, nearly always feature one or more relockers built into their design.
Explore Our Range of High-Security Safes with Glass Relockers