Check for UL or CE marks and make sure everything follows local codes. Look for damage and test with a multimeter if you know how. Tip: Always wear insulated gloves and safety glasses. Good labeling of breakers is very important. Use. This standard describes requirements for numbering and labeling of real property electrical distribution equipment, circuits, and site lighting at Lawrence Livermore National Laboratory. Proper identification prevents hazards, streamlines maintenance, and ensures. Electrical panels and electrical control panels provide electricity to buildings, equipment, and machinery through an organized circuit system. You accomplish this by attaching durable labels that specify which rooms.