Which of the following is an important safety rule to remember when using a crank-up tower?
Why A crank-up tower is held extended by a cable and winch, and if that cable, winch or pulley fails while someone is on it, the sections telescope down and can crush or sever whatever is between them. So the safe practice is to climb only when the tower is fully nested (retracted) or when mechanical locks, pins or blocks are in place to hold the sections independently of the cable. Never trust the winch cable alone to support a climber.
Watch out The choices about painting and grounding are backwards: towers are normally painted for corrosion protection and must be bonded to a good ground system for lightning safety, so the all-of-these option fails too.
Crank-up: nested or pinned before you climb. Never trust the cable with your body.