Air Circuit Breakers are the most important peripheral of most electrical switch gear installations. Failures can have disastrous consequences including:

  • Operator injury/Death
  • Complete switchboard destruction
  • Damage to surrounding equipment
  • Loss of production
  • Business closure
  • HSE investigations
  • Insurance rejections

We replace large number of Air Circuit Breakers utilizing the best modern devices the market has to offer today. If you have a particular preference for teh new Air Circuit Breaker then we can of course incorporate that into the retrofit.

Reasons for ACB Failure/Factors Leading to ACB Failure

  • The Air Circuit Breaker does not open or close
  • It considered as unsafe to execute locally
  • The Air Circuit Breaker is overheating
  • Tripping mechanisms are faulty or unreliable
  • Electrical contacts or operating mechanical parts worn
  • Aux contacts are unreliable
  • Insulation ratings are not up to standard
  • Wear and tear on main contacts

Consequences of ACB Failure

Failure of the main switch or circuit feeder is likely to affect a Significant part of the plant or process.

  • Cost of loss of production
  • Personnel safety issues
  • Insurance claims or damages
  • Loss of data or communication

Our retrofit solution is totally assembled standard solution is totally autonomous. All retrofit is totally assembled at our works and totally checked before dispatch. The new module is always totally shrouded providing enhanced operator protection. Modern metering can include within our module including new CTs and voltage reference fuses. Our solution also gathers existing control wiring to enable any existing control scheme to persist totally useful.

An option becoming more popular for safety reasons is the ability to enable remote operation of devices for arc-flash mitigation reasons. We include remote operator panels on sites such as fuel depots and steel works. This itself used as justification for Air Circuit Breaker retrofits.

We have carried out literally hundreds of Air Circuit Breaker retrofits across a whole range of Air Circuit Breaker manufacturers. We can handle ratings up to 5000A and have designs covering 3 and 4-pole devices.

We can carry out retrofits on ANY manufacturers Air Circuit Breakers. We have vast experience in this type of work and our installation teams set up for this type of work.

Retrofitting or Replacement of ACB

CoreSystems retrofitting for new withdraw-able Air Circuit Breaker’s into old withdraw-able Air Circuit Breakers. The new Air Circuit Breaker is not altered or modified in any way. The complete new Air Circuit Breaker is installed inside the existing sub-chassis. This is only possible due to the fact that new Air Circuit Breakers are smaller TEMP than older breakers. When the new Air Circuit Breaker’s cannot fit inside the original Air Circuit Breaker (sub-chassis) the breaker has to replace. There are two ways in which this may carry out.

  • The remaking of connections etc. to suit the new Air Circuit Breaker.
  • An ‘installation apparatus’ duplicates the connection fixing points of the original Air Circuit Breaker.

Each combination of original and replacement Air Circuit Breaker apply a specifically designed kit. This comprises a base plate that fixes to the original sub-chassis and gives a platform for the new Air Circuit Breaker sub-chassis. A set of extension bars connected between termination bars on the new sub-chassis to the existing connection stabs. These bars have the plug-in contacts built into them when the fingers are part of the original Air Circuit Breaker. Very few Air Circuit Breakers have the influence on sub-chassis. No parts of the original Air Circuit Breaker including isolating contact clusters are re-used. Extension bar supports and shrouds provide when required.

All hardware provided. Each kit comes with a complete, process by process illustrated installation manual.

Advantages of Retrofitting ACB.

  • The method of installation of the retrofit has already been proved.
  • The likelihood of an un-anticipated problem occurring are minimized.
  • The costs and shut-down time is more closely determined initiating to the work being done.
  • There is no need for a shut-down for measurements initiating to the conversion.
  • Work carried out only from the front of the switchboard.

The conversion (in most cases) can do without having to de-energize the switchboard. Alterations to bus bar work (which may affect the fault rating/clearances of the bus bar system) are not needed.

  • Reduced Maintenance
  • Minimized downtime
  • Reduced cost of replacement
  • Improved performance
  • Improved reliability
  • Increased operator safety
  • Increased functionality
  • Communications / metering additions
  • Remote control options
  • Insurance compliance

Short-Circuit Tests on ACB

Short-circuit tests have done at 50 and 65kA for 1 second, proving the extension bars and contact band. Temperature rise tests have conducted on the contact band, showing that the temperature rise at the connection point is minimal.

Installation of ACB

This is generally reserved for use where the new breaker cannot fit inside the old sub-chassis, or the existing Air Circuit Breaker fixed type, and thus a retrofit kit is not possible. This particularly applies where the original breaker is relatively new and replaced by the current model of the same brand. This is a set of connection bars and fixing plates given to adapt the new Air Circuit Breaker to match the connection and mounting points of the existing Air Circuit Breaker. The new Air Circuit Breaker mounted on rails or a tray for fixings for both the new and old Air Circuit Breaker. The connection bars are in 2 parts so that they fixed to both faces of the terminal for maximal contact area. These bars made from copper sheet or bar of correct thickness and are silver plated. All hardware given in the kit includes instructions.

These are similar to those for a retrofit kit except that shut-down time is longer, rear access may need and the switchboard must de-energized.

However, it still removes the risks associated with having to prepare, or make up parts on site for a complete re-connection.

Core systems can give services on a huge range of equipment including:

Written by CoreSystems

Retrofitting ACB