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The Minimum Crane Indicator Every Crane Should Have!

One of the most common yet easily preventable crane accidents is two-blocking a crane.  Two-blocking is the condition where the hoist block impacts with the boom tip.  The results can range from damage to the boom on a telescopic crane to a broken hoist line where the load free falls.

Any two-block accident will cause some damage that can be expensive to repair, possibly put the crane out of commission, and in the worst-case scenario, damage other property or personnel at the job site.

Needless to say, you want to avoid any two-block accident during your crane operations.

There are several regulations that require anti-two-block warning systems on cranes, and in most cases, your crane falls under one of them—either from OSHA, your state's regulations, as a requirement for liability insurance, or as a condition of doing government contract work. In any case, an anti-two-block warning system should be on your crane.

Anti-two-block warning systems are most commonly referred to as ATB, or A2B systems, and the most common ones are the wireless versions when retrofitting a crane.  

Wireless ATB systems are inexpensive and easy to install. They also work on most cranes. They provide the operator with an audio and visual alarm when the crane is close to two-blocking.  They also have an output that can be used with lock-out hardware to stop the crane when the A2B alarm goes off.  

The other common type of ATB warning systems are the wired systems.  

Wired ATB systems provide the same monitoring as the wireless systems; however, their switch and display is connected by a cable either directly on a lattice crane or through a cable reeling drum on a telescopic boom crane.  

Both wireless and wired ATB warning systems do a good job of monitoring and alerting to two-block incidents, and the best fit depends on your crane and work environment.


At Crane Warning Systems Atlanta, we stock, sell, and service wireless as well as wired A2B crane warning system. Our experts will be glad to provide you advice on the best fit for your crane.  We carry the RaycoWylie R147 wireless ATB and the wired model R140. Call 1-877-672-2951 or visit our online store for more information.

Learn more about benefits of crane safety systems here.

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