A method for mounting an LED module on a support comprises providing an LED module comprising a printed circuit board and multiple LEDs mounted on the printed circuit board, a support and a plurality of fasteners, each fastener comprising a head, a pole extending downwardly from a bottom of the head, and a plurality of teeth protruding downwardly from the bottom of the head and surrounding the pole, extending the fasteners through the printed circuit board of the LED module into the support, rotating each fastener such that the teeth thereof scrape insulating layers off a metal substrate of the printed circuit board, whereby a top face of the substrate is exposed and in direct contact with the teeth of the fasteners.