electric electrical electrician electricity energy hazard high power protection risk security sign signal abstract background cell charge communication connection graphic lightning nerve relay surge transfer icon illustration industrial industry internet protect safety clouds iron journey pebbles post pylons rail rails railway railways rocks semaphore Signals sky stones train trains transportation travel voyage weather signpost alarm alert ayto car combo deliver drive emergency engine light lighting orange small special transport vehicle wagon worker concave dish electrical signals electromagnetic feedhorn parabolic parabolic reflector radio waves roof rooftop round satellite dish television tiled tiles