Secondary distribution networks are often established in a circular architecture called a ring. This is important for continuity of supply to enable energy consumption to be transferred from multiple points for the consumer.

Consumer transformers (called distribution transformers) are located at appropriate points on the ring circuit, with their outputs connected to consumption points, and their energy is transmitted via secondary cells.

These cells have at least two circuit elements that provide continuity for the ring, at least one of which feeds a transformer. These circuit elements can be placed in a modular or compact configuration, with each element located in a separate metal tank, as described in section 1.2 above, or with all elements (at least three) located in the same metal tank. The cells in this second option are called RMUs – Ring Main Units.

They are particularly preferred in urban networks because they take up less space.

Ekos Electric can create an RMU by bringing together the desired number of circuit elements. All switching devices, bars and connection elements are made of stainless steel filled with SF6 gas in a single tank. Since all the energized compartments are isolated from the air, they are not affected by external factors such as dust and humidity, and do not require maintenance or cleaning.