Everything you need to know about PCB Contaminated Transformer Oil

Although the chances of coming across a high concentration of PCB on the UK electricity network are very low, it still happens to this day, so it is something you need to be aware of. Especially with the implementation of a deadline of 31st December 2025 to remove PCB Contaminated Transformer oil and equipment from use.

What is PCB?

PCBs (Polychlorinated Biphenyls) are man-made organic compounds which pose risks to human/animal health due to their toxic and bio-accumulative properties. PCB was first introduced as insulating oil and was widely used in the manufacture of capacitors and transformers through the 1950s and most recently in the UK up to 1982. Their use in the production of electrical equipment has been illegal in the UK since 1987.

The impact assessment (IA) relates to the domestic implementation of the revised EU Persistent Organic Pollutant regulation (EU 2019/1021), which came into force on 15 July 2019. The regulation still applies to the UK and requires us to remove equipment containing more than 0.005% and volumes greater than 0.05dm3 of PCBs, as soon as possible and by no later than 31 December 2025.

To implement the regulation, the Department for Environment, Food and Rural Affairs introduced a deadline of 31 December 2025 for holders of equipment contaminated with more than permitted levels (0.005%/0.05dm3) of PCBs, to remove such equipment from use.

Where will you find PCBs?

PCBs were used as dielectric filler liquids in some types of electrical equipment. Examples include transformers, capacitors, electrical equipment including voltage regulators, re-closers, bushings and electromagnets, the oil used in motors and hydraulic systems, lab equipment or appliances and air compressors.

When will PCBs be present?

You can assume that oil-containing devices manufactured prior to 1979, will contain PCB unless you have certification or information to the contrary.

However, it is also possible:

  • That transformers manufactured between 1976-1986 may also contain PCBs.
  • Even if the PCB oil has been replaced by another liquid, significant amounts may still be present.

Some equipment is labelled as containing PCBs but if you come across old equipment with no identifying label you should check with the owner or manufacturer of the equipment.

In the UK, it is more common to come across PCB Contaminated Transformer oil (over pure PCB oil-filled transformers). When PCB oil was used it was often on sites where both mineral and PCB-filled assets were used, this is similar to nowadays when mineral and Midel fluids are used together.

During the maintenance of PCB assets, sometimes the same oil drums were used for emptying and refilling the assets. For those assets containing mineral oil, the maintenance effectively dosed the oil with PCB fluid giving rise to PCB Contaminated Transformer oil.

PCB Contaminated Transformer Oil testing

How to dispose of PCB Contaminated Transformer Oil?

PCBs, PCB waste (including protective clothing that has been contaminated with PCBs) and equipment containing PCBs must only be disposed of by specialist waste contracting firms which are licensed by the Waste Regulation Authority. You must not dispose of PCBs or PCB waste by pouring it into drains, onto land or by burning.

Less than 50ppm: Any transformers containing less than 50ppm of PCB Contaminated Transformer oil are fine and no action needs to be taken.

50ppm – 500ppm: If the transformer contains concentrations of 50 – 500ppm of PCB then the oil should be removed from the network when practically possible and the unit should be flushed and refilled so the concentration is below 50ppm.

More than 500ppm: Transformers containing more than 500ppm of PCB should have the oil removed from the network immediately and the unit flushed and refilled to ensure the PCB concentration is below 50ppm, this may take several flush operations.

How can Bowers help?

Bowers Electricals purchases and disposes of transformers that are no longer needed after an upgrade or replacement. However, prior to any purchase, we require the oil to be tested and PCB certificates to be prepared. Bowers can offer this service before we purchase, or simply if you require to confirm the equipment that you continue to own is compliant with the regulations.

Our maintenance team offer full transformer oil testing. You can view our services here.


Posted on: 04.04.2023
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