PDS Notes – Volume 2, Number 3
PCB’s in Bushings & GE Type U Bushings
Most utilities have an installed base of bushings on substation transformers and breakers. There is a very high probability of 70 – 80% that these existing bushings were manufactured by GE or Westinghouse. This is true regardless of the transformer manufacturer because GE and Westinghouse manufactured about 70 – 80% of all bushings for many years.
It was recently pointed out that in many cases, utilities are not aware that PCBs in bushings can contaminate the rest of the equipment. Also, if these bushings fail, they will have a more significant impact. Therefore, we are providing the history of Westinghouse and GE bushing manufacturing facilities and if they used PCBs.
The probability of PCB content varies by manufacturer. For ABB, it varies by the location where the bushings were manufactured, the year they were built, and even the type of bushing that was manufactured.
- GE Canada: We don’t think they were allowed to use PCBs.
- ABB Munice, IN: Always was a PCB free facility.
- ABB Alamo, TN: Always been a PCB free facility.
- Westinghouse Trafford, PA (aka East Pittsburgh): Type O bushings should have <50PPM PCB (this factory built in 1959 and mainly manufactured circuit breaker bushings).
- Westinghouse Sharon, PA: Type O bushings should have <50PPM PCB, although we are slightly less certain because of possible contamination.
- Westinghouse Pittsfield, MA (formerly GE plant): See table below:
We don’t have any information on the Canadian facilities of GE, Westinghouse, and TTI.
The GE, Type U bushings used a printed herringbone condenser design. This has a history of breaking down over time. It results in a degrading of the dielectric in the condenser of the Type U bushing. These have a fairly high incidence of failure due to these problems. If you would like additional recommendations on testing or replacements of GE Type U bushings, please let us know.
The best way to determine the actual level of PCB contamination in bushings is by testing. Old bushings could have been rebuilt by persons and in places that are unknown, and therefore, could be contaminated to higher levels than previously noted.
Click on the following PDF files for more information.
If you have any questions, please contact us at (402) 596-1991, or email@example.com.