boat cargo discharge freighter Nyberg sand ship shipment unload vessel bolt danger electrical electricity energy flash graphic lightning night power sky storm warning band black cable clip coil components electric electronic isolated maintenance protect red repair static upgrade wire wrist alert amperage amps area backdrop background brown caution copy death electrocute electrocution fence grunge grungy hazard hazardous high icon industry information painted plank planks risk security shock sign space square steel symbol triangle voltage volts wall white wood wooden yellow base bulb cap cost current double-contact-bayonet-base edison-screw-base electric-current embedded-wires emissions filament gas-discharge globe glow glowing incandescence incandescent-light instant-start lamp light light-source lighting luminosity luminous luminous-efficacy sleeve standard stem traditional ultraviolet ultraviolet-emissions ultraviolet-light ultraviolet-radiation blue colours green nature springs water cold glacial glacier ice landscape mountain norway river scree valley