Oil Circuit Breakers – A Brief History

From the turn of the 20^th century Oil Circuit Breakers have been used as an efficient and successful way of detecting and interrupting fault current. The Oil Circuit Breaker still retains its place amongst commonly used Circuit Breakers especially in the 11-33kV range where they have been in use for 50 years or more.

Within the 11-33kV range of Oil Circuit Breakers there were many manufacturers. As transportation of heavy equipment was challenging in the early 1900’s, Oil Circuit Breaker manufacturers were more inclined to supply in to their local areas. For example, in the West Midlands there is an abundance of South Wales Switchgear and GEC/AEI.

Over time many of the switchgear manufacturers were acquired or merged with other companies.  GEC acquired AEI (Associated Electrical Industries), Metropolitan Vickers, British Thompson Houston (BTH) and English Electric throughout the 1960’s and 70’s.  Another prominent switchgear manufacturer that has featured many of the iconic British switchgear names is Hawker Siddley Switchgear. Again throughout the latter part of the 1960s and onwards they bought out or merged with South Wales Switchgear, Brush Switchgear and Whipp and Bourne.

As Oil Circuit Breakers were such an effective and reliable method of arcing control, many of the Oil Circuit Breakers have been in service for 50 years or more.  Due to the critical nature of Oil Circuit Breakers, DNO’s (Distribution Network Operators) and private owners of this equipment still have to keep a tight schedule on maintenance to ensure everything is running efficiently and safely. With Oil Circuit Breakers, once the fault current has been interrupted, the severity of the current can be judged and then post fault maintenance can be performed.  Otherwise maintenance is at a scheduled time.

As part of an Oil Circuit Breaker, the Moving Male and Fixed Female Contacts are used to carry load current and with the addition of oil and an arc control pot, the contacts can effectively break the arc generated under fault conditions.  These contacts get damaged and therefore become inefficient or unable to carry load current.  Although contacts can extinguish lots of minor faults, severe fault currents can damage the contacts rendering them ineffective.

Alcomet has a range of original Fixed Female and Moving Male Oil Circuit Breaker Contacts to assist with the maintenance of Oil Circuit Breakers.  These have been engineered to the highest standards within the UK.  Alcomet stock an extensive range of products from manufacturers such as:

• Brush
• British Thompson Houston
• Crompton Parkinson
• Ellison
• English Electric
• GEC/AEI
• Metropolitan Vickers
• Reyrolle
• Statter
• South Wales Switchgear

For more information

If you have any questions or would like to find out if we stock the Oil Circuit Breakers for your equipment please contact the team on 01384 404488 or via the form below: