Rat & Rodent Resistant Cable Duct Seals For LV MV HV Cables & Substations

Published 20 Apr 2018

• by Chris Dodds T&D - estimated reading time 3 minutes

Sealing Ducts

Wildlife induced power outages are increasingly caused by the invasion of rats and rodents into medium/high voltage electricity substations via unsealed and inadequately sealed cable ducts and then gnawing electricity power cables.

Filoform FiloSeal+HD is a duct sealing system that is able to seal large heavy armoured power (multicore XLPE SWA) and high voltage cables in ducts, bore holes or cable transit frames – providing a strong support system using hexagonal tubes building a re-enterable seal with honeycomb structure.

The duct seal system is extensively approved and used by UK utilities, DNO’s and their preferred ICP (Independent Connection Provider) to protect electrical assets and cables within substations typically operating at 11kV, 33kV, 66kV and up to 132kV from rat attack.

The cable duct seal kits have been extensively tested against pressure, pulling forces, chemicals, gases and hydrocarbons for adequate sealing of LV-HV cables against the danger of flood (water ingress) or gas migration.

Recently, testing was carried out to establish the ability of the duct seal system to resist, repel or prevent rat attack through cable ducts into electricity substations and the following post provides information about the test and their conclusions.

TalkTalk suffered a major outage caused by rodent damage to fibre optic cables in 2017.

Sealing Cables & Ducts

Rat & Rodent Testing

Filoform have carried out tests to assess the physical damage caused to the FiloSeal+HD cable sealing sealant by a group of four rats (two males and two females) which are given free access to the duct seal for a period of four weeks.

The FiloSeal+HD comprises of MD+ sealant with hexagonal tubes as the backing product which was positioned within a metal tube.

Each end of the tube was sealed with 25mm of MD+ sealant ensuring that access to the backing product could only be achieved by significant damage to the MD+ sealant.

This tube was mounted in the center of the cage and consequently, the male and female sides of the cage had access to opposite ends of the tube.

Test cage before start of study

Immediately before rats placed in cage – side exposed to males	Immediately before rats placed in cage – side exposed to females
After one week of exposure – side exposed to males	After one week of exposure – side exposed to females
After four weeks of exposure – side exposed to males	After four weeks of exposure – side exposed to females

Duct Seals | Substations

Conclusion

The results at the end of the four week study indicated that there was no apparent difference in the damage caused by the male rats in comparison to the female rats and though the damage increased over the duration of the study the MD+ duct sealant was not penetrated by the rats and the hexagonal backing tubes were not exposed or damaged.

No abnormalities, ill health or behavioural changes occurred to the rats during the study and all four rats achieved satisfactory body weight gain during the exposure period.

Several hard red pieces were observed in the large intestines of one female and in the stomach of one male and one female. There were no other abnormalities observed at the post mortem macroscopic examination at study termination on Day 29.

In conclusion as the hexagonal tubes were not damaged after 4 weeks of exposure with direct access, therefore, it is reasonable to assume that different backing products will be protected to a similar degree, when enclosed by MD+ cable duct sealant.

THORNE & DERRICK are national distributors LV, MV & HV Cable Installation, Jointing, Substation & Electrical Equipment – we service UK and global businesses involved in cable installations, cable jointing, substation, overhead line and electrical construction at LV, 11kV, 33kV and EHV.

Since 1985, T&D have established an international reputation based on SERVICE | INTEGRITY | TRUST.

Contact us for 3M Electrical, ABB, Alroc, AN Wallis, CATU Electrical, Cembre, Centriforce, CMP, CSD, Elastimold, Ellis Patents, Emtelle, Euromold, Filoform , Furse, Lucy Electric & Zodion, Nexans, Pfisterer, Polypipe, Prysmian, Roxtec, Sicame, WT Henley.

Invitation

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