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Electrical Distribution

Electrical Distribution

The effectiveness of Belzona solutions for oil and SF6 gas leaks, as well as our general maintenance solutions have been proven through these applications resulting in prolonged equipment life.


What makes us different?

Cost Effectiveness

  • One of the key features of Belzona products for transformer repairs is their ability to bond to oily/manually prepared surfaces overcoming the traditional challenges of the application. Even live leaks can be stemmed and sealed in-situ due to the high adhesion, structure and curing capabilities of the product.

Ease of Use and Safety

  • Belzona products are cold applied, eliminating hot work, and have been designed to be easy to use and safe as possible for the end user.


  • Belzona products are resistant to a wide range of chemicals and heat and in addition provide excellent corrosion protection therefore offering long-term solutions.

Why does it work?

Oil contamination represents a non-polar, greasy layer that conventional polymers will struggle to displace, i.e. no intimate contact with the metal surface resulting in little or no bond. Belzona's products are tolerant of surface preparation, effectively displacing the oil from the surface creating strong electrical affinity with the metal substrate, and as a result bond to the surface effectively.


Electrical transformers and switchgear use oil and gas as electrical insulators, which have been proven to provide good performance and safety. Inherent environmental problems however occur due to localised equipment failure and defects, resulting in leaking of the oil or sulphur hexafluoride (SF6) gas.

Transformer oil and SF6 gas leaks are often caused in the following ways;

  • Flexible/compressible sealing materials are used to create a leak proof joint, but with time lose their sealing properties. For example on transformers the seal is produced by tightening down the covers onto a cork gasket which over time becomes more rigid and the seal is lost. With switchgear mastics are known to dry out and fail similarly.
  • Corrosion on the sealing faces
  • Distortion when covers are tightened down incorrectly
  • Mechanical impact damage
  • Corrosion

Environmental Damage

Consequence of Transformer Oil and SF6 gas leaks

SF6 Gas Leaks

Sulphur hexafluoride (SF6) is a highly potent greenhouse gas used in the power industry for insulation and current interruption in electrical equipment, such as transformers, switchgear busbars and circuit breakers. The gas has a global warming potential of 22,800 times that of carbon dioxide.

In response to its high global warming effect, the Kyoto Protocol officially announced the aim of decreasing SF6 gas down to an agreed level by 2012 along with carbon dioxide, methane and nitrous oxide. Attempts have also been made to decrease levels of this gas under regional environmental regulations.

Transformer Oil Leaks

In the case of transformer oil leaks, oil can pollute the earth, which may eventually cause contamination of groundwater. When the insulating oil in a transformer is PCB (polychlorinated biphenyl), which is a persistent organic pollutant, it enters the environment through both use and disposal and is potentially highly toxic to biological objects (humans and animals) with health effects including skin conditions, and a link to cancer. Many regulations have therefore been enacted for prevention of PCB leaks, such as the Pollutant Release and Transfer Register (PRTR), and the problem has been also addressed by national acts in many countries.

It is therefore clear that leaks to the environment are potentially significant and the owner of the substation has a huge responsibility to ensure that transformer leaks are not left unrepaired.

Traditional Maintenance Challenges

Traditional repairs that would require interruption to supplies, dismantling or complete replacement of equipment or installation of seals / gaskets are not popular. In-situ repairs that do not require supply interuption would be the first choice but the problem with such leaks is that they are traditionally difficult to complete;

  • Surfaces may be contaminated with dirt and oil
  • There is normally the requirement to bond to manually prepared surfaces
  • Access and geometry of the component can present additional challenges

It is therefore essential for any solution provider that they address all of these challenges.


With over 55 years experience, Belzona's systems and techniques have enabled us to develop repair composites and overcome the traditional difficulties of bonding to oily / manually prepared surfaces.

Electrical substation and distribution organisations worldwide have benefited from Belzona's solutions in addressing problems including;

  • Leaking fins, flanges, pipework, bushes and welds
  • Corrosion attack
  • Damage through erosion, mechanical and vandalism
  • Containment areas
  • Facilities maintenance

The effectiveness of Belzona solutions for oil and SF6 gas leaks, as well as our general maintenance solutions have been proven through these applications resulting in prolonged equipment life, avoiding high replacement costs and minimising interruptions to power supplies.