Video Microtrenching (Narrow Trenching) Fibre Optic Cables - Emtelle Vertex Products & Solutions

By Chris Dodds on 29th October, 2015

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Video Microtrenching (Narrow Trenching) Fibre Optic Cables - Emtelle Vertex Products & Solutions

Microtrenching (also known as slot cutting and narrow trenching) is a civils technique used for the fast deployment of fibre optic cable for all aspects of fibre connectivity. It can be used for FTT Premises in towns and cities and also used for trunk applications along with other civils technologies like Mole ploughing and traditional digging.

In a Guest Blog from Emtelle we will learn about the benefits and best practice techniques used within microtrenching.

Fibre to the Property (FTTP) or Fibre to the Home (FTTH) initiatives in many countries around the world have created the requirement to install extensive networks of optic fibres in order to make high speed broadband (up to 100MPs) widely available.

However, in order to install such large networks in an economic and timely manner, and with minimal disruption to traffic and residents, the requirement for new techniques for laying ducts into highway infrastructure has emerged.

The most popular alternative to traditional open trench excavation is the use of micro-trenching, because it is up to thirty times faster and only 20% of the cost of traditional trenching.

Emtelle Vertex

Pictured: Microtrenching


Whilst the formation of micro-trenches has developed alongside the technology of fibre networks, one crucial piece of the new technique has received little attention. That is the reinstatement of micro-trenches to infill and repair the road surface.

Consent is normally required from the highway asset owner to install the fibre network, and an acceptable form of reinstatement must usually be agreed in advance of the works.

For clarity, the following terms will be used throughout this document but are defined below because the terminology varies in different countries around the world:

  • Road - a surface, either flexible or non-flexible designed to carry vehicles. Typically also called the highway surface or pavement.
  • Footway - a surface adjacent to the road designed for pedestrian traffic primarily. Typically also referred to as sidewalk (USA) and pavement (UK).
  • Micro-trench - narrow trench or slot cut in the road or footway surface to accept the fibre duct.
  • Reinstatement - Infilling and repairing the road or footway surface to its original level and condition

Video: Safetrack Micro-trench Infill Installation

This video shows the effective reinstatement of a micro-trench using Safetrack MTI. The trench is cut at a width of 20mm to a depth of 150mm. Fibre optic cables are then installed between two packer layers of foam.

Safetrack MTI Yellow is then installed to approximately 10mm from the surface with Safetrack MTI Asphalt Grey being used capping off the final 10mm. 

Safetrack MTI is a cold applied, free flowing, self compacting quick curing resin which can be trafficked within 30 minutes of the installation being complete.

The benefits of Microtrenching are that the deployment is fast compared to traditional methods with the ability to install between 300 metres and 1000 metres of fibre cable in a working day (depending on trench depth, width, backfill materials, access and location).

  • Designed to be installed by blowing
  • Low weight
  • Small diameter
  • All dielectric design
  • Ultra low friction sheath


Microtrenching techniques involve the actual Microtrench, 25mm up to 130mm wide and 150mm to 500mm deep. Then there is an absorbent layer to protect the microducts, then after microducts have been installed, a strong filling compound is added to protect the Microducts and also put strength back into the road / pavement.

Emtelle also have additional products such as tracer wires and marker tapes which can offer additional protection and tracking.

Microtrenching can be deployed in carriageways, concrete and tarmac pavements and even in the verge (but sometimes mole ploughing can be faster in the verge). 

The most suitable products for installation into a Microtrench are subducts or microducts and Emtelle have been supplying these products, specifically for Microtrench applications since the initial deployments in the UK in 2004.

There are a number of different microtrenching machines on the market. These vary depending on the specific application and size of micro-trench which is required.

The widths of the blades vary anywhere from as small as 15mm up to 150mm with some machines capable of removing the as dug material and suitably preparing it for backfill in the same process. Other operators use a double bladed Stihl saw with the blades 100mm to cut a narrow trench. A mini-digger is then used to take the trench to the required depth.

VertexEmtelle's Vertex range of products are specifically designed for use with microtrenching applications. Microducts as big as 25mm (feeder network) can be incorporated into an Emtelle Vertex product, which will accept a 288 fibre cable.

The smallest sized microduct currently being used in microtrenching products is 5mm (access networks) and can be fed to the customer without the need for any connectors in the route, or a hybrid product incorporating various microduct sizes can be designed.

Pictured: Vertex from Emtelle

Vertex from Emtelle

All Emtelle Vertex products are designed specifically to customer requirements which allows the product, microtrench and network to be used to its full potential.


  • Further Reading :

Video : Emtelle GS150 Fibre Blowing Unit - Blow 115 Metres Of FTTx Cable In A Minute

Emtelle Power Duct (Class 1 33kV) - WPD & ENATS Utility Specification 12-24 Revision B





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Category:  Cable Laying & Cable Pulling

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