A battery-operated palm stapler, an insert for holding a fastener, and a method of installing a fastener using the palm stapler. The stapler includes a housing with a telescoping barrel extending outwardly therefrom. An insert is engaged in the barrel's bore and is held in place by magnets. The insert body defines a slot for receiving fasteners therein. The slot extends from a top wall of the body to a bottom wall thereof. At least one magnet is provided in the body adjacent the slot and is used to hold fasteners in a correct orientation for installation. A sensor probe provided in the body is operable to detect if voltage is carried in electrical cables adjacent which fasteners are to be installed. The probe deactivates a hammer actuating mechanism if voltage is detected. Inserts holding different types of fastener may be selectively engaged with the palm stapler.