The minimum power supply recommended for most houses today is a three-wire 240-volt, 200-ampere service, especially if the house is larger than 3,000 square feet, if heavy-draw electric appliances such as electric cooking ranges or clothes dryers are planned, or if such features as central air-conditioning and swimming pool pumps will be installed.

A good indication of the power supply available at any site is whether two or three main wires enter the weatherhead fitting on the roof or side of the house. If only two wires are present, the dwelling has 110–120 volt power throughout. If three, then 220–240 is available at the meter.

The circuit box is where the main electrical service is split into separate circuits. There should be at least 12 to 15 circuits to handle the electrical needs for most homes. The cover on the panel should be able to be tightly closed, and the main wires entering the box should be neatly and securely affixed to the wall. Home wiring must be grounded properly. Proper grounding provides a path for electricity to safely travel from a defective appliance, tool, outlet, fixture, or other component, to the earth or ground. Your local building code will state what is required for proper grounding in your area.

Electric clothes dryers and cooking ranges require special 240-volt receptacles. These receptacles differ slightly but significantly, so make sure the dryer and range receptacles will fit your appliances. Electric water heaters are wired directly to the house’s electric cable. Electric ranges can also be wired directly.

Because most major appliances run on electricity, you’ll want to

• Make sure the brand is reputable
• Consider if the features of each appliance will do what you need them to do
• Evaluate the warranties on each one
• Check for energy efficiency
• Know if service contracts are available