Correctly Sealed Cable Ducts Will Protect From Ingress Into Potable Drinking Water

Published 16 Jul 2018

Sealed Cable Ducts

  • uploaded by Chris Dodds - Thorne & Derrick Sales & Marketing Manager

The following information is provided courtesy of Severn Trent Water as part of their series of Lessons Learn Bulletins which highlight the potential use or adoption of products to ensure cleaner, safer and more reliable distribution of water supply – specifically this short update is focussed on duct sealing to prevent pollution of potable drinking water.

Brief Description

The Whitacre / Warwickshire team identified a shortfall in the way cable ducts are sealed following installation of new and the maintenance of existing assets.

This was identified as part of coliform investigations where there is a potential for water ingress into injection chambers, reservoirs and back wash tanks. Lack of correct duct sealing in this instance resulted in water entering a level probe chamber with the potential to pollute potable drinking water.

Duct Sealing

Sealing Cable Ducts

Several options to securely seal cable ducts have been investigated with support from Water R&D. As a result of findings Asset Creation updated the STW design manual for E&M Plant Electrical Design (DM0106-03) and issued a technical bulletin informing key departments, ensuring that the new minimum standard is adhered to.

Two duct sealing kits were used and approved by PH&S, both provided similar results.

PLEASE NOTE: These kits are not DWI Reg 31 approved and must not be used where direct contact with potable water occurs. Any proprietary seal kit used must be of the type listed in the Water Industry Mechanical & Electrical Specification 3.02 (SPC 0302-W302).

Lessons Learnt

Share at your Comm Cells with your operational and maintenance teams.

• During routine inspections check for any cable ducts which could possibly allow ingress into reservoirs or injection chambers which could lead to a water quality failure?
• Contact either of the above for any assistance for procuring and advice on installing the sealing kits.
• Track any next steps via your Comm Cell, raise WQ U/C and sign off when complete.

Sealed Cable Ducts

Duct Seals

Examples of installed duct sealing systems

Cable Duct & Cable Protection

Thorne & Derrick supply an extensive range of underground cable duct and protection covers suitable for LV MV HV cable installations – this includes Tape Tile 11kV and Stokbord Covers 33kV used to protect underground power cables pulled and laid into trenches.

To promote the installation of cable into duct a labour-saving range of cable lubricants is available to facilitate friction-free cable pulling and reduce damage to cables. See our range of cable ducts suitable for low, medium and high voltage power and utility cables.

Key Product Categories: Duct Seals | Cable Cleats | Cable Glands | Electrical Safety | Arc Flash Protection | Cable Jointing Tools | Cable Pulling | Earthing | Feeder Pillars | Cable Joints LV | Joints & Terminations MV HV 

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