Many installers use battery-powered impact drivers for rooftop installations. Impact wrenches are typically rated for torques of 10 to 100 times the torque ratings for bolts in your system. Use an appropriate driver that prevents overtightening and always check bolts with a torque wrench. Consider marking bolts with a paint pen once they have been torqued for the last time as a confirmation method. Refer to manufacturer specs for bolt torque specifications.