Mechanical Safe Lock Groups
In my last blog post I outlined the similarities and differences between seven types of mechanical safe locks. In this post I will outline the criteria used to determine how mechanical safe locks are rated or grouped by the Underwriters Laboratories’
768 standard. The four safe lock groups in use today are: Group 2, Group 2M, Group 1, and Group 1R
1. Group 2
safe locks offer the lowest level of resistance to expert manipulation techniques and meet the minimum requirements for build tolerances, durability, and accuracy. The three wheel version of this lock group offers 1,000,000 possible combinations; whereas the four wheel version offers 100,000,000 possible combinations. Group 2 locks typically have between ±0.5 and ±1.25 number dialing tolerances. These locks come with a relock trigger; a brass four-way drive cam that allows for right hand (RH), left hand (LH), vertical up (VU), or vertical down (VD) mounting; metal wheels; and a die cast, brass, or zinc push-pull lever.
2. Group 2M
safe locks offer a minimum of two hours of resistance to expert safe “cracking” techniques. These locks are usually found on safes rated for tool resistance of either 15 or 30 minutes. These three wheel locks offer 1,000,000 possible combinations and come with a torque adjuster to maintain proper wheel pack tension; a relock trigger to thwart punch attacks; false wheel gates; an eccentric roller in the lever nose; a four-way drive cam that allows mounting RH, LH, VU, or VD; brass or aluminum wheels for a long, dependable life; and a brass push-pull lever.
3. Group 1
Group 1 safe locks offer at least twenty hours of resistance to expert non-destructive opening techniques. These locks are often found on containers rated for torch and tool resistance of 30 minutes. These locks have special features not found in other locks, including: a thermal relock component, a stainless steel lockbolt strong enough to resist more than 600 pounds of force, and an adjuster to allow for the precise setting and maintenance of wheel pack torque.
4. Group 1R
Finally, group 1R safe locks also offer at least twenty hours of resistance to expert covert attaches. They are typically used on safes rated for torch, tool, and explosive resistance. In addition to having the features of a group 1 lock, locks rated 1R come with acetal resin wheels in order to thwart x-ray imaging attaches.
Safe locks come with different ratings to serve different security needs. Group 2 locks are typically used by home homeowners that require a minimal level of security, group 2M locks are usually used by business owners that require a medium level of security, group 1 locks are most often used by banks, credit unions, and pay-day loan outlets that require a high level of security, and group 1R locks are almost always used by government departments that require a maximum level of security.