Most ready mix and concrete products plants have significant investments in electric power tools. Unfortunately, electric power tool maintenance is often given little thought. Maintaining electric power tools usually is not complicated. The following guidelines will help ensure maximum tool safety, efficiency, and longevity. In order to maintain tools, keep in mind the following: keep accurate and complete repair records; inspect a tool before using it; repair should only be performed by a trained technician; perform standard safety tests--a ground wire continuity and resistance test, leakage current test, and a high-voltage insulation test; check brushes when a tool is in the shop; before resuming operation, test to see that the tool operates properly. Understand these guidelines for proper tool usage: always read the owner's manual to familiarize yourself with the controls and operation of the tool; don't force the tool into the work; use the right size tool for the job; never carry a tool by it's cord; don't use a tool if the cord is worn or frayed; use a vise or clamps to secure work; keep tools sharp and clean; do not operate electric tools in gaseous or explosive atmospheres; keep air vents clear; store tools in a dust-free area; operate a tool only at its rated voltage.