FROM CONCEPT

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Value: Six figures
Voltage: 33kV
Duration: 6 months

Multi-Utility Trench Installation

The client appointed JSM as a specialist contractor to deliver multi-utility service installations for the BMCE new-build commercial and residential high-rise development on Hearn Street, Hackney.

THE CHALLENGES

Works were carried out within a narrow, highly congested street, requiring continuous access for businesses, residents, and a UKPN substation, while coordinating multiple stakeholders and delivering complex multi-utility installations.

WHAT WE DELIVERED

Installation of multiple utility ducts and mains, including power, communications, and gas, in a highly congested urban environment.

11kV

power ducts

33kV

power ducts

specialisms used

  • Site supervision
  • Excavation
  • Multi-utilities installation
  • Reinstatment
  • Traffic management
  • Project management
  • Risk management
  • Stakeholder management
“The key to this project was a coordinated operational approach, integrating different utility requirements into a single delivery plan while managing access and disruption in a busy street environment.“
Joe Scanlon
Associate Director

FROM CONCEPT

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Value: Multi million
Distance: 21,647m
Duration: 4 months

Hollow Core Fibre Connection – Data Centre

The client required 21.6km of hollow core fibre (HCF) to be installed in East London.

THE CHALLENGES

Challenges included securing borough council approvals and navigating street cabling conditions while maintaining HCF integrity.

WHAT WE DELIVERED

  • Works included detailed route surveys, planning, and securing all necessary permits and approvals
  • Installation of 2,282 m of ductwork, 14 chambers, and proving of 21,093 m of ducting to ensure route integrity
  • Installation of 21,647 m of 4-fibre HCF cable and 21,647 m of 192-fibre singlemode cable, including splicing and testing to specification
  • Construction deliverables included as-built drawings, fibre routing SLDs, and final test results to confirm compliance

 

 

2.3km

New Ductwork 

14

New Chambers 

4 fibre

HCF Cable 

specialisms used

  • As-built drawings
  • Testing
  • Hollow Core Fibre
  • Splicing
  • Fibre installation
  • Permits
“Strong coordination and operational control were key to delivering this project efficiently in a busy urban environment.“
Toby Ford
Head of Operations

FROM CONCEPT

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TO CONNECTION

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Value: Six figures
Distance: 7.6km
Duration: 45 days

Hollow Core Fibre Connection – Data Centre

The client required 7.6km of hollow core fibre (HCF) to be installed in London Docklands.

THE CHALLENGES

Communication and approvals from borough councils, along with the challenges of installing cabling through street environments while maintaining HCF integrity, added complexity to the works.

WHAT WE DELIVERED

  • Works included detailed route surveys, planning, and securing all required permits and approvals
  • Installation of 246 m of ductwork, 15 chambers, and proving of 6,332 m of ducting to ensure route integrity
  • Installation of 7,618 m of 8-fibre hollow core fibre (HCF) cable and 7,618 m of 432-fibre singlemode cable, including splicing and testing to specification
  • Post-construction deliverables included as-built drawings, fibre routing single-line diagrams, and final test results to confirm compliance

 

264m

New Ductwork 

15

New Chambers 

8 fibre

HCF Cable 

specialisms used

  • As-built drawings
  • Ductwork
  • Chamber
  • Hollow Core Fibre
  • Splicing
  • Fibre installation
  • Feasibility
“Delivering this project in a busy urban environment required a strong operational focus and close coordination throughout. By keeping teams aligned and responding quickly to challenges on site, we were able to maintain quality and keep the programme moving.“
Toby Ford
Head of Operations

FROM CONCEPT

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Biodiversity Opportunities | Bird nesting and Bat Roosting Boxes

 

THE CHALLENGES

Protected UK species such as nesting birds and bats have experienced significant population declines, birds by 11% since 1970 and bats over the past century, mainly due to habitat loss, changes in agricultural practices, and reduced food sources.

THE BENEFIT

Monitoring of installed bird and bat boxes by licensed London Bat Group members has fostered collaboration between National Grid, JSM, and Croydon Council, benefiting protected wildlife in South Croydon.

23

New trees

1SP

Sparrow terrace

2F

Schwegler bat box

specialisms used

  • Schwegler design
  • Vegetation management
  • 1SP sparrow terrace
  • 2F Schwegler bat box
  • Bird nesting
  • Bat roosting
“This kind donation will enable us to replace some of the old wooden boxes with the new Schwelgler boxes. The sparrow terrace will make a great addition in Wandle Park, which has a thriving sparrow population.“
Meike Weiser
Croydon’s Community Conservation Partnership Officer

FROM CONCEPT

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TO CONNECTION

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Value: Multi Million
Voltage: 33kV
Duration: 10 months

20MVA Battery Energy Storage System

The client requested the design, construction, and commissioning of a 20MVA Battery Energy Storage System (BESS) compound.

THE CHALLENGES

Coordinating works was challenging, with DNO-contracted non-contestable activities taking place alongside JSM on a constrained site, while the installation of 11 batteries, each weighing 32 tonnes, required a complex lifting operation due to limited space.

WHAT WE DELIVERED

  • Works included detailed design and approvals
  • Installation of civil and electrical infrastructure such as plinths for 11nr batteries and 6nr transformers, 700m of 33kV cabling, a 2-panel 33kV switchboard, auxiliary transformer, and fibre connections
  • Temporary works were constructed to support a 300 ton crane that installed the 11nr batteries, each weighing 32 ton

6nr

Transformers

2 panel

33kV

switchboard

700m

33kV

cabling

specialisms used

  • Principal designer
  • Compound construction
  • Compound earthing
  • DNO switchroom & substation
  • Installation of 11nr batteries
  • LVAC supplies
  • Jointing & Terminations
  • Hot and cold commissioning
    with Energisation
“Strong coordination and operational control were key to delivering this project efficiently within a constrained site.“
Martyn Crocker
Operations Director

FROM CONCEPT

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TO CONNECTION

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Value: Multi Million
Voltage: 132kV
Duration: 18 months

132kV DATA CENTRE CONNECTION

The client required the design and build of a 70MVA 132kV Data Centre connection in Hemel Hempstead, Hertfordshire.

THE CHALLENGES

Complex construction is required, including HDD beneath the M25 under strict National Highways constraints, installing plants and ducts across the River Colne, and safely routing ducts over petrol pipelines and high-pressure gas mains.

WHAT WE DELIVERED

  • JSM constructed a 132/33kV DNO and customer substation and a 16km 132kV dual circuit in highly congested roads
  • The Special Engineering Difficulties (SEDs) included crossing the M25. Horizontal Directional Drilling (HDD) was employed to ensure no disruption to traffic
  • Horizontal Directional Drilling (HDD) was also used to cross a river whilst meeting all environmental standards

16km

132kV Dual circuit 

30

132kV Joint bays

60

Fibre chambers

specialisms used

  • Auxiliary transformer design
  • Compound construction
  • Compound earthing
  • Motorway monitoring
  • Horizontal directional drilling
  • Jointing & Terminations
  • Hot and cold commissioning
    with Energisation
“This project demonstrates our ability to deliver large-scale, high-voltage infrastructure in highly constrained environments. By combining technical expertise with a collaborative approach, we’re able to provide solutions that support the growing demand for data centre capacity.“
James Cooper
Head of Business Development

FROM CONCEPT

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Value: Multi Million
Voltage: 132kV
Duration: 21 days

SPECIAL ENGINEERING DIFFICULTY

A cable crossing over the River Colne and Colne Brook was required to connect a Data Centre to Iver Substation.

THE CHALLENGES

Limited engineering options make it challenging to meet infrastructure needs while also protecting the environment.

WHAT WE DELIVERED

  • Bridge-mounted and Horizontal Directional Drilling (HDD) methods were ruled out, leaving open-cut excavation as the only option
  • Works were completed in 21 days following two years of planning and ecological safeguards

Dam

Installation

Designs

Permits and Ecological surveys

specialisms used

  • Cable Crossing
  • Open cut excavation
  • Dewatering
“This project required a careful balance between delivering essential infrastructure and protecting a highly sensitive river environment. With challenges around working in a live watercourse, managing dewatering, and protecting local wildlife, detailed planning and close monitoring on site were critical to minimising impact and maintaining full compliance.“
Claire Parsons
Environmental Manager

FROM CONCEPT

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Value: Multi Million
Voltage: 132kV
Duration: 10 months

132kV DATA CENTRE CONNECTION

The DNO client required the delivery of a dual 132kV ducted cable and fibre system as part of a new 80MVA connection into the DNO’s network, supporting a 132/11kV substation and Data Centre in Dagenham. 

THE CHALLENGES

Crossing the Beam River required Horizontal Directional Drilling through an area of historical landfill, introducing complexities around ground conditions, contamination risk, and stability. At Hacton Bridge, insufficient cover for standard cable installation created additional design constraints, while extensive traffic management and coordination with local authorities were necessary to minimise disruption during works.

WHAT WE DELIVERED

  • JSM planned, managed, and coordinated all phases of this multi-million project, including detailed design, permitting, construction, commissioning, and handover
  • JSM managed a 7km cable route across Barking, Dagenham, and Havering, including excavation, cable laying, and jointing, while coordinating with stakeholders to overcome engineering and traffic challenges
  • The Special Engineering Difficulties (SEDs) included a specialist river crossing using Horizontal Directional Drilling (HDD) under environmental permits while minimising disruption through proactive stakeholder engagement

132kV

DUCT AND FIBRE SYSTEMS DELIVERED

80MVA

CONNECTION INTO DNO’s NETWORK

specialisms used

  • Auxiliary transformer design
  • Principal Contractor]
  • Compound construction
  • Compound earthing
  • Motorway monitoring
  • 132kV Cables & Duct installation
  • Horizontal directional drilling
  • Jointing & Terminations
  • Hot and cold commissioning
    with Energisation
“This project demonstrates the value of a fully integrated approach, where design, delivery and stakeholder engagement come together to support the client’s wider objectives. It’s a great example of how we bring certainty to complex schemes.“
Stephen Bradley
New Business Director

FROM CONCEPT

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Value: Multi Million
Distance: 21.8km
Duration: 4 months

Hollow Core Fibre Connection – Data Centre

The client required the installation of new 33kV circuits and fibre infrastructure, including ductwork, chambers, and a 33kV switchroom, to support network upgrades and connectivity using hollow core fibre in north London.

THE CHALLENGES

Communication and authorisation from borough councils for cabling works posed a challenge, alongside difficulties in routing cables through street environments while maintaining HCF integrity.

WHAT WE DELIVERED

  • JSM planned, managed, and coordinated all phases of this multi-million pound project, including detailed design, permitting, construction, commissioning, and handover.
  • The team installed 1,983metres of new ductwork, constructing 12 chambers, and proving 21,172metres of ducting.
  • The team installed and spliced a total of 21,807metres of Hollow Core Fibre and Single mode Fibre cables.
  • Works also included supply and installation of a 33kV switchroom and 3.1km of cable ducting with cable pull and jointing, completed to specification and tested for compliance.

33kV

CIRCUITS

1,983m

NEW DUCTWORK

21,8km

TOTAL CABLE INSTALLED

specialisms used

  • As-built drawings
  • Ductwork
  • Hollow Core Fibre
  • Splicing
  • Fibre installation
  • Feasibility
“From an operational perspective, this project was about maintaining consistency and quality across a busy urban route. By keeping teams aligned and responding quickly to on-site challenges, we were able to deliver the works efficiently while maintaining high standards throughout.“
Toby Ford
Head of Operations

FROM CONCEPT

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Value: Multi Million
Distance: 130km
Duration: 10 months

130km Fibre Installation

The client required a new network build spanning 130km along a route from Welwyn to Slough that included canal and bridge crossings.

THE CHALLENGES

Complex multi-borough delivery with challenging third‑party access and dependencies, combined with a long, constrained route. Additional difficulties included engineering constraints and limited access points such as canal towpaths.

WHAT WE DELIVERED

  • JSM planned and managed the multi-million pound project, including stakeholder engagement, surveys, redesign, construction, Horizontal Directional Drilling (HDD), ducting, fibre installation and testing.
  • The team installed 130km of fibre with 64 joints.
  • Over 100 Special Engineering Difficulties (SEDs) were managed, including the use of barges and pontoons to manage access and carry out works safely.

130km route

WELWYN TO SLOUGH

64

JOINTS

100

SEDs MANAGED

specialisms used

  • Surveys and route proving
  • Duct roping
  • Chamber build
  • Duct supply and Installation
  • 432f Fibre Installation
  • Splicing and testing
  • Project management
  • Permits and notices
  • Traffic management
“Projects of this scale rely on strong planning and a clear delivery strategy from the outset. By structuring the route effectively and maintaining close coordination across stakeholders, we were able to keep progress consistent and deliver the scheme efficiently.“
Rob Mills
Head of Planning & Maintenance