Slipping hazards and cable pulls can make for a nasty combination. For example, you can slip and fall into cable pulling gear. Or worse, catch yourself and get your fingers crushed by rotating parts.
The gravel beds commonly installed around outdoor electrical equipment provide poor footing. Setting down a sheet of plywood can alleviate this problem. When setting up on more solid surfaces, look for wet spots left by lift trucks or other equipment. Clean up as needed.
A good safety practice that most people don't follow is to periodically check your work shoes/boots for serviceability. Don't try to get every penny's worth of use out of footwear. If the soles are worn, replace the shoes/boots or have them resoled. Also, make sure they fit snugly but comfortably. If your foot is moving around inside the shoe, you are much more likely to slip or twist your ankle. Sometimes a thicker pair of socks (or double-socking) solves this problem.