Elements, couplers, systems, and methods for joining two or more trough members. A locking element for a coupler of a cable trough system includes a frame member including a shaft, a pawl member including first and second ends, and defining an aperture, the shaft of the frame member extending through the aperture so that the pawl member pivots on the shaft, and a member positioned to engage the first end of the pawl member to pivot the pawl member about the shaft into a locked position. When a force is applied to the first end in a direction opposite to that exerted by the member, the pawl member moves about the shaft into an unlocked position.