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Belzona® Transformer Leak Repairs On Tertiary Box



Power (POWR)



Valves, Pipes and Fittings (VPF)


Customer Location:

Electricity Substation, UK


Application Date:

September 2012


Application Situation:

Exterior/Rooftop of Super Grid Transformer Tertiary Box



The transformer had been suffering from extremely high losses of transformer oil. Following a site survey, oil discharges were evident at many of the flange and bolt joints to equipment located to both the interior and exterior of the noise enclosure. The root cause of the oil leaks was found to be the tertiary box located in the noise enclosure on the rooftop.



Belzona® 1221 (Super E-Metal)

Belzona® 1161 (Super UW-Metal)

Belzona® 5831 (ST-Barrier)



Mild Steel


Application Method:

The application was carried out in accordance with  modified versions of Belzona Know-How System Leaflets VPF-8 & 11. The tertiary box substrate was prepared before Belzona® 1221 was used to stem any active oil leaks. The flange joint was sealed using Belzona® 1161 incorporating Belzona® 9341 (Reinforcing Tape). Bolt and nut heads, together with male studs were protected by either bridging tape or tight fit former, then fully encapsulated using a disposable former containing Belzona® 1161. Following the curing process, the formers were removed and all of the repair areas were coated with Belzona® 5831.


Belzona Facts:

The leak sealing project was successful. In recharging the transformer with oil to the correct level, neither the flange or bolt heads showed any visual evidence of further leakage. The clients request that the studs be protected prior to encapsulation of the bolt heads was also met.


Photographs Description

  1. Tertiary Box during survey
  2. Completed application
  3. Completed application
Case study pic one


 Case study pic two


 Case study pic three




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