Workscope: MVCB Major Overhaul

• The circuit breaker will be received and inspected for worn, damaged and missing components
  

  -	A visual inspection of the entire circuit breaker will be done specially for items such as damaged wiring, bent secondary contacts, rusted frame, etc.
  -	Any item found damaged will be recorded and a suitable replacement identified.

• Box barriers and arc chutes will be removed, cleaned, tested and inspected for erosion and damage
  

  -	Arc chutes will be inspected for excessive carbon, cracks and other defects in the throat area of the arc chute.
  -	Asbestos arc chutes will be cleaned and stored as per GE hazardous materials safety rules.
  -	Box barriers will be inspected for damaged insulators and components and cleaned using the appropriate solvents.
  -	Any item found damaged will be recorded and a suitable replacement identified.

• The circuit breaker will be functionally and operationally tested to determine any additional work required
  

  -	The breaker will be operated and inspected for binding in the moving components.
  -	Individual electrical components will be tested as required.
  -	The circuit breaker will be inspected for applicable manufacturer updates.
  -	Any additional work required will be quoted separately.

• Primary bushings will be inspected for signs of corona tracking and damage
  

  -	The bushings will be inspected for damaged insulation and tracking.
  -	The bushings and breaker frame will be inspected for signs of stationary primary disconnects leaking compound.
  -	Any item found damaged will be recorded and a suitable replacements identified.

• Insulating parts and contact assemblies will be completely disassembled
  

  -	Disassembly and cleaning of the contact structures reduces the amount of resistance in and heat generated by the current carrying path, and removes all of the dried lubrication.
  -	The contact assemblies will be removed from the circuit breaker and disassembled into component parts.
  -	All contact assembly components will be inspected for damage and wear.
  -	All components will be cleaned and the contact structures re-assembled using extended life lubricants.

• Current carrying components will be thoroughly cleaned and inspected for wear and damage
  

  -	All components will be cleaned and parts requiring silver plating will be plated (silver-plating will be quoted separately).
  -	The contact structures will be re-assembled using extended life lubricants.

• Insulating parts will be thoroughly cleaned and inspected for damage and deterioration
  

  -	Any item found damaged will be recorded and a suitable replacement identified.

• The mechanism will be completely disassembled, and cleaned, and parts painted
  

  -	All parts will be cleaned and inspected for wear or damage.
  -	Painted parts will be re-painted.

• The frame will be cleaned and painted.
• The mechanism will be assembled and lubricated, utilizing an extended life lubricant. If the breaker has old type fiberglass "tuffloc" bushings, an aluminum/bronze bushing upgrade kit will be installed
  

  -	The old type fiberglass "tufloc" bushings were originally installed at the factory on GE breakers. Over a period of time, these lubrication-free bushings tend to wear. If the bushings have been mistakenly lubricated, the wear is more rapid. The factory recommended solution is replacement with new brass bushings.
  -	The addition of the second prop spring for GE breakers was installed to improve the reliability of circuit types of breakers. The prop spring kit will be installed as needed.
  -	The mechanism will be re-assembled with the appropriate parts replaced.
  -	All bearing and sliding surfaces within the mechanism will be lubricated.

• Contact assemblies and insulating parts will be assembled and lubricated
  

  -	The contact structures will be re-assembled using extended life lubricants.
  -	The contact structures and insulating parts will be inserted into the breaker frame.

• Circuit breaker wiring will be inspected for damaged wires and correctness
  

  -	The wiring bundle will be inspected for damaged or cut control wiring.
  -	Any replacement wiring, if needed will be quoted separately.

• Mechanical adjustments will be checked and adjusted in accordance with the manufacturer's specifications
  

  -	Wipe and gap measurements will be taken as required.
  -	Mechanism adjustments, such as trip latch and release latch wipes, will be completed as per manufacturer's specification.

• Interlocks, mechanical and electrical, will be checked for proper operation and adjusted to manufacturer's specifications, if necessary
• Arc chutes and box barriers will be installed.
• Final electrical tests will be performed
  

  -	Contact resistance tests - A digital low resistance ohmmeter will be used to record the contact resistance and compare it to the manufacturer's specifications. High resistance in the contact structure can cause excessive heat in the breaker and prematurely dry out the lubrication.
  -	Insulation resistance tests - A 1,000-volt megger will be used to determine the condition of the circuit breaker's insulation to the ground and across phases.
  -	Functional operational tests (electrical and manual) -The breaker will be operated manually and electrically to verify proper operation.
  -	Power factor test (optional) - If requested, the circuit breaker primary bushings will be power factor tested and the results compared to industry standards of acceptability.
  -	Time motion analysis (optional) - If requested, the circuit breaker opening and closing time and speed will be verified and compared with the manufacturer's specifications.
  -	High potential tests (optional) - If requested, the circuit breaker will be high potential tested according to manufacturer's specifications.

• Test data will be included as part of the final customer report
  

  -	All test data received will be included with the circuit breaker test report. The test report will be shipped with the equipment.

• GE recommended equipment upgrades, if applicable, will be quoted separately.

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