For most electrical projects, you'll need to turn off the power to the circuit you're working on. If you don't have a circuit tester handy, test the circuit by plugging a hairdryer or a radio into the outlet that operates on that circuit.
Several kinds of circuit testers are available. For example, you can use a multimeter (figure A) to determine whether the voltage is on, whether the circuit is complete or broken, how much voltage is present and whether the polarity is correct. Another basic circuit tester is the plug-in type (figure B), which lights up to indicate whether the voltage is on and operating in the correct polarity.

When you use tools for electrical work, it's essential that they have insulated rubber handles.

Some of the more common tools you're likely to need include wire snips (figure C),

Needle-nose pliers (figure D),

Phillips/Cross Point and flat-head screwdrivers (figure E)

Wire Stripping tools and Crimpers (figure F).

These Multipurpose tools can strip, cut and crimp wires of various gauges; in addition, they can cut bolts and be used as pliers.