A stress inducing device for inducing stress into a fiber optic cable is useful for detecting a person attempting to breach a security fence by climbing over the security fence. A stress inducing device is attached adjacent to a top of each fence post of the security fence. A fiber optic cable runs adjacent to a top of the security fence, and passes through each of the stress inducing devices. Once activated, a pressing member of the stress inducing device will pinch the fiber optic cable therein causing an alarm. The stress inducing device will be activated if a person leans a ladder against the fiber optic cable or the stress inducing device itself, or if a person attempts to open or tamper with the stress inducing device.