Businesses in electricity transmission and supply are involved in moving electricity across the network and selling it to homes and organisations. Transmission businesses operate high-voltage lines, cables and substations that carry electricity over long distances from generators towards local distribution networks. Their work includes monitoring network capacity, maintaining equipment, managing faults and arranging connections for new generators or large users. Transmission is distinct from local distribution, which delivers electricity through regional networks to individual premises. Electricity suppliers buy or arrange electricity for customers and provide the account and billing services associated with its use. They may offer different tariffs, including fixed or variable rates, and deal with meter readings, payments, account changes and billing queries. Some suppliers also arrange smart meter installation and support customers who have difficulty paying.