Substation Flood Defence

Cable Entry Sealing

Recent Flooding events in the UK have highlighted the vulnerability of our infrastructure to cope with high water levels. Electricity substations in particular were affected calling into question existing levels of flood protection. The Pitt Review was written to give independent advice on how we must change our infrastructure in order to be better prepared for future floods; the floods in his words were "a reminder of the need to pay greater attention to improving the resilience of critical infrastructure against flooding.”

Following the Pitt Report the Energy Networks Association produced a report covering the resilience to flooding of substations. One of the solutions to the issue of substation flooding in this report was preventing "groundwater seepage through ducts”.

GPT have developed expertise in sealing cable entries into substations and since 2011 we have performed duct sealing works on over 100 substations leaving them safe from water ingress via their cable ducts and protecting the public from blackouts.

Protecting substations from flooding also reduces humidity levels within substation buildings. High humidity can cause partial discharge and switchgear to malfunction; therefore preventing moisture from entering the substation is a high priority for DNO’s.

We can utilise a range of technologies to seal ducts into substations depending on site specific conditions/requirements. We have a mechanical system ROXTEC and a mastic type sealant CSD RISE (for more information on the systems see the individual pages).

We have vast experience in providing these applications to a variety of Utility companies in difficult environments such as confined spaces or where there is running water entering the substation.

We also specialise in sealing ducts where current seals have failed or the ducts have been installed with no forethought to the requirement for duct sealing. For more information see the sealing failed cable entries page.

Our substation cable duct sealing is tailored to meet the site specific requirements but can include:

  • Easy re-entry for adding, removing or replacing cables
  • High levels of water and gas tightness*
  • Fire protection
  • Flexible installation arrangements where time/logistical factors are critical
  • Adapted to seal irregular shaped openings
  • Seals ducts in wet conditions
  • Trefoil and large power cable requirements
  • Consideration of gas resistance
  • Consideration of submersion in petrol, diesel, transformer oils or other chemicals

*All work is quality checked and scored on the basis of the work. A perfect seal cannot always be guaranteed.

Substation Duct Sealing Case Studies

substation water ingress flood defence using roxtec
substation cable duct sealing NOFIRNO (CSD RISE)

Extracts from legislation and guidance

“In all cases, it should be noted that resilience to shallow flooding (up to 600mm) can often be secured by relatively simple protection for key assets, such as sealing entries to control rooms”

Energy Networks Association (ENA) Substation Resilience to Flooding report

"If possible design and construct ducts and chambers that prevent the ingress of water."

GPP 20 Dewatering underground ducts and chambers

Need advice for services and products? Call us now 01656 741 799

Geo Pollution Technologies (UK) LTD - company number - 04689357


GPT head office is based in South Wales and covers all areas of South Wales, West Wales and Mid Wales including Cardiff, Swansea, Bridgend, Newport, Port Talbot, Powys, Llanelli, Neath, Pembrokeshire and Aberystwyth.

We also cover the South West of England from our premesis in Exeter including Cornwall, Devon, Taunton, Redruth, Truro, St Austell, Falmouth, New quay, Torquay, Paignton, Bristol, Plymouth, Bath, Gloucester and Somerset, .

We also operate across the midlands, London, Birmingham, Leicester, Northampton, Derby, Stoke, Nottingham, Coventry, Liverpool, Worcester, Southampton, Swindon, Manchester, Sheffield, Slough, Heathrow, Leatherhead and Surrey.