A screwdriver is arguably the single most common tool used for electrical work. Standard screwdrivers work just fine in many cases, but they have one big drawback for electrical work: At least half of the tool is a bare metal shaft, which is a very good conductor of electricity. If any bare metal of the tool contacts a live electrical current, the whole shaft becomes live. And if the shaft is touching a metal box, another electrical part, or your finger, bad stuff can happen. That's why electricians use insulated screwdrivers for certain jobs, and it's a good idea for homeowners to follow the professional example.
What Is an Insulated Screwdriver?
An insulated screwdriver is a specially designed tool that has a tough, non-conductive plastic cover over its shaft and handles. Only the tip of an insulated screwdriver is exposed. The insulation protects the user from the possibility of touching live parts of a circuit and the grounded walls of the box or other equipment. By having the shaft of the screwdriver protectively coated with a non-conductive material, it is safe to hold the screwdriver's shaft for balance. In addition to the personal safety benefit, insulated screwdrivers also can prevent damage to delicate electronic parts that might be destroyed by an electrical short.
More Than a Plastic Coating
Many standard screwdrivers have handles made of non-conductive material, but this is not a reliable guarantee that the handle is properly insulated. Ideally, a true insulated screwdriver is not only designed inside-out for electrical safety, but it also carry voltage ratings specifying the amount of electricity it can resist. A professional-grade screwdriver typically is rated for 1,000 volts. That's plenty for household electrical systems.
Of course, these tools are made of steel, so the non-conductive coating must be intact to do its job. Therefore, it's important to inspect your screwdrivers for damage before each use. This is not the screwdriver to reach for when you need a makeshift pry bar, floor scraper, hammer, etc. Save your cheap import tools for those ugly jobs.
Why Not Use Electrical Tape?
Wrapping a metal tool shaft with electrical tape may offer a small degree of safety, but it doesn't provide the protection of a truly insulated tool. For one thing, the insulating material must be of a consistent thickness to provide real protection. Wrapping a tool with tape is anything but consistent.
Second, there's no way to discern how much protection electrical tape will give you. How much voltage your wrapping can handle is an unknown variable. And third, electrical tape does not have a strong bond and is easily damaged. If you're cranking a tool and it slips and meets a sharp metal box edge, you could easily breach the homemade insulation and get right down to the bare metal.
The bottom line: if you need an insulated tool, there's no appropriate substitute to one designed for that purpose.