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Retrofit Circuit Breakers

Why Retrofit?

  • Fault level upgrades - where the fixed portion needs to be compatible with a proposed enhanced rating
  • Remote control of switchgear – many originally manufactured ocb’s have manually operated  mechanisms that cannot be converted to electrical release or motor charged mechanisms
  • Troublesome individual breakers on a multipanel switchboard where there are no technical or economical reasons to change the switchboard
  • Desire to upgrade the moving portion but cannot practically consider installing new switchgear (i.e. process industry)
  • Less maintenance and asset management costs (no oil, frequency of maintenance reduced, post fault maintenance reduced)
  • Loss of expertise on particular ranges of circuit breaker
  • Lack of availability of spares for oil circuit breakers
  • Change of duty – increased frequency of switching
  • Increase in circuit rating from 400-630A (or upgrade from 400-1250A if other internal components changed)

No busbar outage is necessary to conduct the retrofits so there is no interruption of service.

When retrofitting circuit breakers that are utilised for direct on line motor starting, consideration should be given to the installation of surge arresters.

What Switchgear Support Ltd can offer

We have experience with over 5,000 retrofit installations and can offer the complete package from initial consultation, to choice of circuit breakers, to final removal and disposal of the original breakers via fully licensed means.

In particular we have extensive knowledge of Brush Switchgear type VSI (single busbar), VTD (double busbar) ranges and South Wales Switchgear type C/D ranges of retrofits with unparalleled knowledge of the original fixed portions of switchgear.

Taking advantage of individual circuit outages, we can:

  • Convert existing oil filled VT's to cast resin VT's
  • Upgrade existing current transformers to suit better protection and metering
  • Alter protection relays from electromechanical to electronic
  • Supply and install telecontrol facilities for remote control and indication or provide differing forms of remote switching operations to suit clients needs

We are also able to retrofit the following types of equipment:

  • Brush Switchgear VBA/VBC/VBAD/VBCD
  • Reyrolle LMT, LMT23T, LMT2 ranges

For all retrofits offered, the circuit breakers have been fully type tested to IEC60056 or IEC62271.  The certified ratings are:     

Rated Voltage   12/13.8 kV   
Rated Current 400A- 1250A, & 2000A
Frequency 50/60 hz
Symmetrical breaking current  25kA, 31.5kA or 40kA
Rated making current 62.5kA, 78kA or 110kA
Rated Power Frequency withstand  28kV/36kV 
Basic Impulse level
Short time current (3secs)
25kA , 31.5kA or 40kA

Relevant Case studies:

Guernsey Electricity
Associated British Ports