Our daily routine involves electricity of some sort, whether you glance at your alarm clock wash your clothes or use power tools, knowing the basics of how these things function will help you to be safe and take care of the appliances that are in your household.
To begin with, it is good to know how much voltage the appliance you are using needs to function. Most appliances run on either 120 or 220/240 volts. Your washing machine may run at 220 volts so therefore it needs to use one single outlet, whereas something smaller would run at 120 volts and it can share an outlet with something else. Think of it like water going through a pipe, the more water pressure is like more voltage being used. When thinking of voltage, something else to keep in mind is variation in voltage, which is expected in most appliances and can be handled fine with no problem unless you are using electrical equipment that is very sensitive.
Another important principle to understand in electricity is resistance. Resistance is measured in Ohms (Ω), and if you keep with the water in the pipes illustration, it means using a big enough pipe, or conductor, for the current needed. Not only is the size of the wire important, but also the material being used, this is why most metals are used in wiring because electrical current can easily pass through it. Copper is an ideal conductor and has a low resistance rate, and if using an extension cord make sure it is the correct size for the application. Hopefully, these basic explanations can help you to understand the electricity running throughout your house.
Dave Graham, Tempest Home Inspection. Calgary Alberta