Abstract: The present disclosure concerns a jam detection and safety system for machines prone to jamming, such as a baler. In particular embodiments, the system is implemented in a horizontal baler having a shear bar and a hydraulic ram that advances material being baled past the shear bar into a compression chamber. The system includes a strain gage mounted on the shear bar and a controller that is electrically connected to the strain gage. The controller receives strain signals from the stage gage and compares the strain of the shear bar to a predetermined strain threshold corresponding to a jamming condition. If the strain exceeds the predetermined threshold, the controller automatically deactivates the ram, such as by disconnecting line power from the baler and/or by turning off the control power of the baler.