Reduce the scope of power failure, usually installed properly disconnect switches the line segment

Primary distribution network wiring methods are commonly used in radial and ring two. The former refers to the distribution main and branch radially to its scope of jurisdiction power; latter is two power air circuit breaker lines in the region Circuit breaker a ring. Obviously, no spare radial wiring less investment, but reliability is low. To reduce the scope of power failure, the line disconnect switches are usually installed properly segmented. Ring line is also equipped with contact switch, normally open loop operation.
Secondary distribution mcb circuit breaker of distribution transformer secondary lead line to the line between the home user, the component system composed. Also known as the low-voltage distribution networks. In addition to its wiring radial and ring, the key users in the city can be dual loop wiring, electricity load is high density urban areas tend to use grid style.