Low Voltage Circuit Breaker Recondition Program

 

General Requirements

 All work performed and parts utilized in the refurbishment of Low-Voltage circuit breakers shall be in accordance with the Original Equipment Manufacturer’s tolerances and specifications unless otherwise noted herein.

 For each operation, EPIC shall visually inspect circuit breaker for obvious damage and “As Found” condition, noting the customer name, and record observations and findings.  The information will follow the circuit breaker through the refurbishment, and preventative maintenance process.  Any damage will be immediately reported.

Materials

All materials, equipment, and parts utilized for refurbishment shall be in accordance with the Original Equipment Manufacturer’s specifications and service advisories.

EPIC shall provide and maintain all test equipment utilized in the refurbishment of the circuit breakers.  All testing of the refurbished circuit breakers shall be done by and on the premises of EPIC. All test equipment shall be calibrated and traceable to the National Institute of Standards and Technology.  Traceability shall be provided by certificates as requested.

Standards

The circuit breaker shall be refurbished and tested in accordance with the OEM Standards or latest edition of applicable standards.

Low-Voltage Circuit Breaker Refurbishment

Note:    All parts replaced will be maintained by EPIC for a minimum period of 90 days in order to allow customer to inspect the replaced parts at their option.

“As-Found” Testing and Preliminary Inspection

Primary contact resistance using 10 amps dc as a minimum.

Insulation Resistance test of primary and secondary circuits.  Insulation resistance of primary circuit shall be performed using 1,000 VDC as a minimum.  Secondary circuits shall be tested at 500 VDC unless otherwise recommended by the circuit breaker manufacturer, or as requested by customer.

Ensure synchronism of contacts in opening and closing operations is within manufacturer’s recommendations.

TRIP – minimum/maximum rated control voltage

CLOSE – minimum/maximum rated control voltage

Check the integrity of vacuum interrupters, if applicable, by applying ac hi-pot voltage across the contacts of an open breaker in accordance with manufacturer’s recommendations.

Verify circuit breaker operates freely without binding or tripping free.

Verify proper operation of circuit breaker indications (Open, Closed, Spring Charged, Spring Discharged, etc.)

Verify that cycle counter advances by 1 for each complete cycle (1 Close and Open operation), if applicable.

Verify proper operation of the spring charging motor/mechanism.

Verify proper operation of the anti-pump feature.

Inspect each of the following major assemblies and record observations.

  • Arc chutes
  • Primary disconnects, and main and arcing contacts
  • Mechanical and electrical operators
  • Interlocks
  • Auxiliary disconnects
  • Frame
  • Position indicators
  • Interphase barriers

Recondition

The circuit breaker will be completely dismantled down to the last movable part for inspection and cleaning.  Customer to be advised of any deviations from acceptable criteria as provided by manufacturer.  Replacement of any component will require customer authorization.

The frame and parts of the circuit breaker shall be either repainted or re-plated, as required, in order to restore them to their original finish.

Clean all arc chutes, barriers, and insulating parts.  After cleaning,   inspect for cracks and deterioration.  Utilize manufacturer’s criteria for acceptable condition of all components.  Replace if necessary.

Clean all current carrying components by using a method which will not deteriorate original plating which is still intact.  Clean all non-current metal parts by methods which remove all foreign material but do not adversely affect the materials dielectric or structural properties. Note - If more than 50% of the main contact surface is damaged, worn, or cracked, the main contact shall be replaced.  If the contact surfaces require more than “dressing up”, they can be rebuilt to manufacturer’s original specifications or better.

Inspect for cracks, deterioration, or worn areas with special consideration being given to bearings, springs, cams, followers, and pivot areas.

*If customer requires, all mechanism bearings and bushings shall be replaced.

Inspect all terminal blocks and secondary contact blocks for cracking or breakage.  Replace as required.

The auxiliary circuits of the circuit breaker shall be rewired, if necessary, using conductor rated for the particular voltage of the circuit breaker with flame retardant insulation.  Conductor temperature and ampacity ratings shall meet or exceed that of the original manufacturer.  Ring type terminals shall be used for termination of all control wiring where applicable. 

Adhesive backed mounts for cable ties may be used as a method for securing control wiring.

Remove all old lubricants and re-lubricate mechanism and all pivot points with circuit breaker manufacturer or industry approved lubricants.

Re-assemble per manufacturer specification.  Allow hold points for customer source surveillance, if required.

“As-Left Testing”

The circuit breaker shall be tested upon completion of the refurbishment work to determine the “As-Left” condition.  The circuit breaker shall be tested in accordance with the following electrical tests.

Electrical operation – close, trip, trip free, and electrical interlocks.  Ensure synchronism of contacts in opening and closing operations is within manufacturer’s recommendations.

Primary contact resistance using 10 amps dc as a minimum.

Insulation Resistance test of primary and secondary circuits.  Insulation resistance of primary circuit shall be performed using 1,000 VDC as a minimum.  Secondary circuits shall be tested at 500 VDC unless otherwise recommended by the circuit breaker manufacturer.

Minimum/maximum close and trip test at minimum/maximum rated control voltage test

The circuit breaker shall be tested in accordance with the following mechanical tests:

Mechanical operating mechanism – proper function

Mechanical interlocks – proper function

Primary contact – alignment, pressure, wipe, penetration and over travel

Mechanical operation – close, trip, indicator operation, and manual trip pressure loading.

Equipment Identification

EPIC will affix a test sticker to each refurbished circuit breaker which bears our name, phone number, date of refurbishment, and EPIC job information to ensure future traceability of the work and component.  If required, customer information can also be included.

The original manufacturer’s nameplate shall be visible and left in place and all obsolete data shall be marked as appropriate.

Quality Assurance

EPIC will include with every circuit breaker a copy of final test sheet that will include all as left conditions.

Test Reports

A hard copy and electronic copy of the test report shall be supplied for each circuit breaker.  The test report shall include test results obtained during the “as found” and “as left” with all discrepancies identified, and a listing of parts replaced.  The test report shall include the customer name, location, circuit breaker serial number, circuit breaker rating, mechanism type, mechanical test results, electrical test results, and any pertinent observations or comments made by the test engineer.  These data sheets shall be submitted to the Technical Engineer for review, and with each breaker upon shipment.

Delivery

Normal delivery, less any parts requirements, will be 2-4 weeks on a quantity of 4-8 circuit breakers.  Larger quantities will require 4-6 weeks.  (Major replacement parts such as arc chutes, operating mechanism, chair moldings, etc. may increase delivery time)