Fiberglass is encouraged in cases ever dealing with electricity (even wood ladders can be a conductor sometimes).
Follow hierarchy of safety to determine steps: 1) Eliminate risk/hazard (turn off all power, lockout) 2) Substitute (higher risks with lower risks) 3) Engineer a solution (reinvent ways to control electrical energy) 4) Awareness (reveal all sources of energy) 5) Administrative controls/communication 6) PPE