A grounding clamp includes a safety lock-out which locks the operation of the clamp in the absence of a hot-stick. A clamping member cooperates with a frame having an arm, and is selectively biasable by a user to translate the clamping member relative to the frame to clamp a conductor between the clamping member and arm. The lock-out cooperates with the clamping member to prevent the translation of the clamping member unless in the presence of an insulating tool such as a hot-stick.