Customer meters measure the amount of electricity used in a structure. They are typically found on the outside of a building or inside an external wall.
Service wires pass through the meter and then connect to a service panel, which directs electricity into individual circuits that serve different areas of the structure. Each of these circuits has a fuse or circuit breaker, which will cut the power if there is a short circuit or electric overload. Circuits in residential structures usually carry 120 or 240 volts, while circuits in industrial buildings may carry up to 10 kV.
First responders should never attempt to disconnect an electric meter. Doing so can create a deadly electrical arc.