Something is defined as 'electrical' or 'electric' if it uses electricity to function, is involved with the production or transmission of electricity, or is in some other way related to electricity.

The boat runs on an electric motor. My dentist recommends I get an electric toothbrush. You use electrical when you are talking in a more general way about machines, devices, or systems that use or produce electricity. Electrical is typically used in front of nouns such as equipment, appliance, and component.