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Loadbreak Interface Shield FAQ Thomas & Betts, Elastimold


Q. I am quite sure that they will be used, but the ID Buttons (currently yellow) will continue to be used??? A. No, we are changing to a Red ID Button on 15kV & and a Blue ID Button on 25kV so that the bushing with the Interface Shield can be identified with an elbow or insulating cap installed.


Q. What does PBT stand for? A. Wikipedia definition: Polybutylene terephthalate (PBT) is a plastic that is used as an insulator in the electrical and electronics industries. It is a thermoplastic crystalline polymer, and a type of polyester. PBT is resistant to solvents, shrinks very little during forming, is mechanically strong, heat-resistant up to 150°C (or 200°C with glass-fibre reinforcement) and can be treated with flame retardants to make it noncombustible.


Q. I noticed that Emold is eliminating the vent ring on the 15kV interface as part of this enhancement. I think customers will want to know Elastimold's justification for this action. Please share with me the reason(s) for this so we can properly inform our customers. A. 15kV Non-vented Loadbreak Interface Venting of the loadbreak interface was introduced as a solution to the "Partial Vacuum Flash-over" phenomena that was typically experienced on 25kV and 35kV class loadbreak products in cold climates or high altitudes. Thomas & Betts initially used four (4) notches that were cut into the shoulder of the bushing insert for venting (vacuum relief) of the receptacle cuff mating area. Later this feature was changed to include a vent ring that was molded into the shoulder of the bushing insert as a more efficient way of obtaining the vents. While it was felt that partial vacuum was not producing switching flash-overs in 15kV class loadbreak products, it was thought that adding the vents would aid in separation of the connectors during hotstick operations. Consequently, vents were added to 15kV inserts and eventually to insulated parking bushings, parking stand arresters, bushing surge arresters and bolted elbows with taps. However, the addition of the vents on 15kV loadbreak interface eliminated the "popping" sound that operators were used to hearing. The absence of the "popping" sound was believed to give operators the perception that the Elastimold insert/receptacle did not latch/seat as well as other manufacturers' similar products. After careful consideration during the development of the Elastimold interface shield, it was determined vents were not needed on the 15kV inserts and related products.


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Loadbreak Interface Shield FAQ

Loadbreak Interface Shield FAQ Thomas & Betts, Elastimold

As a result, the interface shield appearing on the Elastimold loadbreak insert and related products will once again provide a smooth shoulder at the base of the interface. This objective is consistent with prior 15kV designs and the other two domestic manufacturers who also do not provide vents or other Partial Vacuum Flash-over solutions on their 15kV loadbreak products.


Q. Why should we accept this? A. The new interface shield is being offered as an asset over our competition. It reduces the likelihood of the rubber sticking along the loadbreak interface that many customers have cited as an past issue.


What does the bulletin mean exactly when it notes that the shield is filled with EPDM? A. The PBT shield, which is molded separately, is placed in the mold along with the support tube and semi-con jacket. EPDM insulation fills the cavity within the PBT shield and around the support tube.


Q. Is the new interface compatible with the existing grease now in use? A. Yes; a test report to address this issue is available.


Q. What tests have been performed? A. Test report numbers 282-17-8017 and 283-17-8017 summarize the testing and the results.


Q. Why the red interface? A. The color loading of the PBT material for the 15kV and 25kV parts was chosen to be consistent with IEEE Std 386, Table 3.


Q. Did the internal components change? A. All of the internal components are unaltered to provide the same reliable current transfer as the existing bushing inserts.

10 Q. When will we get a sample?

Q. We need samples of each. Do we order them or will they be sent to us? A. Initial 15kV and 25kV insert sample orders have been placed and shipped. If you did not receive any samples or need addition customer sample, please enter a sample.

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Loadbreak Interface Shield FAQ Thomas & Betts, Elastimold

11 Q. Will this drive up cost?

A. Pricing for both the 15kV and 25kV bushing inserts will not be changed due to this change.

12 Q. Will the existing inserts still be available?

A. Because of the tooling that is affected to add the new PBT shield, the current inserts will be discontinued. The timing of this will be announced by Marketing in the near future.

13 Q. Do the part numbers need to be revised?

A. With the exception of deleting the suffix (1) from the existing products, the part numbers will not change.

14 Q. Is Elastimold saying that their existing inserts have interface (smoothness)

problems? A. Elastimold is offering the bushing inserts with the PBT shield to improve the operating issues (sticking) if there is no lubrication.

17 Q. Will the interface shield be added to other loadbreak connectors?

A. We plan to add the interface shield to all the other Loadbreak Interfaces.

18 Q. When will all of the loadbreak connectors have the new interface shield?

A. The adaptation of all Loadbreak interfaces will take some time, basic 200A Loadbreak products and accessories first, arrester next, followed by 200A/600 series reducing taps. This could take as long as 18-24 month to complete them all.

19 Q. Does the new interface shield affect the interchangeability with other

manufacturers? A. The new PBT Interface shield does not affect interchangeability with other manufactures.

20 Q. Are there MSDS certificates available for this new material?

A. Yes


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Loadbreak Interface Shield FAQ


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