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Ring Main Units

Ring Main Units

OTDS supply a large range of ring main units as standalone items or to be used in conjunction with our transformer and switchgear packages.

Our range includes extensible and non-extensible ring mains up to 36kv. Circuit breakers, switch disconnectors and fused switchgear are all in our range of SF6 or Oil insulated switchgear. 

To enquire about our range Ring Main units please email your requiements to enquiries@otds.co.uk     

A wide range of products can be coupled with this switchgear, creating the possibility of combining circuit breakers, extensible switchgear and metering units to provide a complete multiple panel switchboard without the additional need for cabling and onsite connections,

The Purpose of a Ring Main Unit

Safety and reliability play an indispensable role in the smooth operation of a power distribution network. Essentially, ring main units are designed to promote an uninterrupted power supply within a secondary distribution system and protect one or two transformers from transient currents in an open ring network.

Ring main units are most commonly used in the UK. Developed in the early 1940s, these units were developed to meet demand for the new 13A fused socket outlets that were introduced in Britain after the Second World War. As the ring main solution has come to the fore in recent decades, OTDS become one of the country’s leading suppliers of versatile, high standard ring main units for a variety of applications. Our units are available in a wide range of configurations and in both extensible and non-extensible forms.


  • 12 - 36kv options
  • Fully extensible
  • Oil or Gas insulated
  • Indoor and outdoor IP54 rated


  • Commercial and retail applications
  • Oil and gas industry
  • Rural electrificaiton
  • Mining industries

Technical description in progress

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