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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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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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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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

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

21MVA Battery Energy Storage System

The client required the design, construction, and commissioning of a 21MVA Battery Energy Storage System (BESS) compound in Broadditch, Kent.

THE CHALLENGES

Site earthing presented a challenge due to the 33kV overhead line connection and the planned future 11kV connection, requiring careful consideration of combined fault contributions and differing clearance times. In addition, site constraints made plant installation difficult, as the six 32-ton batteries required a complex lifting operation into position.

WHAT WE DELIVERED

  • 6nr batteries
  • 3nr transformers
  • 460m of 33kV cabling,
  • 2-panel 33kV switchboard,

6nr

Batteries

460m

OF 33kV CABLING

3nr

TRANSFORMERS

specialisms used

  • Compound construction
  • Compound earthing
  • DNO switchgear & substation
  • Battery Installation
  • Duct installation
  • LVAC supplies
  • Jointing & Terminations
  • Hot and cold commissioning
    with Energisation

 

“From the outset, the project relied on careful design integration and coordination on site to manage constraints and ensure safe installation. That approach was key to achieving a robust and compliant end result.“
Martyn Crocker
Operations Director
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Value: Multi Million
Voltage: 66kV
Duration: 16 months

66kV Electrical Installation

The client required a new cable installation comprising single, dual, and triple 66kV circuits and pilot cables along a 10km route in the London Borough of Hillingdon, connecting into SSE’s network at Iver.

CHALLENGE

Utility crossings faced significant constraints: inadequate duct capacity at the River Colne bridge and high-risk congestion near the River Pinn due to existing high-voltage and telecoms infrastructure. Additional environmental and health risks included flooding, Weil’s disease, and potential impacts on habitats such as bats.

WHAT WE DELIVERED

  • JSM planned, managed, and coordinated all phases of this multi-million project, including detailed design, permitting, construction, commissioning, and handover.
  • The team installed three 66kV circuits to SSE and IDNO standards across Uxbridge and West Drayton, navigating congested roads and utilities.
  • The Special Engineering Difficulties (SEDs) included two specialist river crossings under environmental permits while minimising disruption through proactive stakeholder engagement. Achieved by creating a temporary dam and installing a flume pipe to divert the water and enable open-cut works.

10km

route

66kV

circuits

11kV

circuits

SPECIALISMS USED

  • Cable installation
  • Principal contractor
  • Environmental permits
  • Special Engineering Difficulties (SEDs)
  • Traffic management
  • Safe excavation
“This was a complex route through busy urban areas, so planning and coordination were critical from day one. By taking a proactive approach to constraints and working closely with stakeholders, we were able to keep the works moving while minimising disruption to the local community.“
Stephen Bradley
New Business Director

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Value: Multi Million
Voltage: 33kV
Duration: 12 months

33kV Solar Farm Connection

The client required the design, installation, and commissioning of a 35MVA 33kV DNO switchroom and cable route in Essex.

THE CHALLENGES

An adjacent third-party project required excavation along the same route, creating a high risk of disruption to local residents, alongside the challenge of securing design approval from UK Power Networks

WHAT WE DELIVERED

  • Works included detailed design and approvals, installation of a 3.6km 33kV cable route, and post-construction commissioning and energisation
  • An adjacent 3rd party project required a collaborative shared trench arrangement

35

MVA

3.6km

33kV CABLE ROUTE

33kV

 DNO

 SWITCHROOM

specialisms used

  • Principal designer
  • Compound construction
  • DNO switchroom & substation
  • 3.6km cable route
  • 33kV Cables & Duct installation
  • LVAC supplies
  • Jointing & Terminations
  • Hot and cold commissioning
    with Energisation
“Careful planning and close collaboration were key to navigating the approval process and coordinating the works. That allowed us to maintain programme and deliver a reliable outcome without unnecessary disruption.“
Martyn Crocker
Operations Director

FROM CONCEPT

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Value: Multi Million
Voltage: 33kV
Duration: 8 months

33kV Solar Farm Connection

The client required the design and delivery of a 20MVA 33kV DNO switchroom and cable route for a solar development in Staveley, Derbyshire.

THE CHALLENGES

Design approval from NGED presented a key challenge, which was addressed by working closely with the client, their contractors, and NGED to develop an acceptable design. Additionally, potentially disruptive streetworks required careful management, with the JSM Streetworks team collaborating with the local highways authority to secure permits and minimise impact on the local community.

WHAT WE DELIVERED

Supplied and installed a 33kV DNO switchroom including battery chargers and a metering room, along with 3.1km of 33kV cable duct installation, cable pulling, and jointing

20

MVA

3.1km

CABLE DUCT

 INSTALLATION

33kV

DNO

SWITCHROOM

specialisms used

  • Compound construction
  • DNO switchgear & substation
  • 33kV Cables & Duct installation
  • LVAC supplies
  • Jointing & Terminations
  • Hot and cold commissioning
    with Energisation
“Early coordination and close collaboration were key to keeping this project on track and minimising disruption.“
Martyn Crocker
Operations Director

FROM CONCEPT

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TO CONNECTION

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Value: Multi Million
Voltage: 33kV
Duration: 8 months

33kV Solar Farm Connection

The client required the design, installation, and commissioning of a 15MVA 33kV DNO switchroom and cable route in Basildon, Essex.

THE CHALLENGES

The cable route needed to cross the busy A127 into London, creating congestion and logistical constraints. At the same time, a nearby third-party project planned to excavate along the same route, increasing coordination complexity and the risk of disruption to local residents.

WHAT WE DELIVERED

  • JSM provided detailed design and approvals, supply and installation of the switchroom with battery chargers and metering room, and 4.2km of 33kV cable ducting with cable pulling and jointing
  • Horizontal Directional Drilling (HDD) was used to cross under a busy road
  • Collaboration with an adjacent 3rd party project sharing the same route avoided multiple excavations on a busy road

15

MVA

4.2km

CABLE DUCTING

33kV

DNO

SWITCHROOM

specialisms used

  • Principal designer
  • Principal contractor
  • Compound construction
  • Compound earthing
  • 4.2km cable route
  • 33kV Cables & Duct installation
  • LVAC supplies
  • Jointing & Terminations
  • Hot and cold commissioning
    with Energisation
“Delivering this scheme required a joined-up approach from design through to energisation, with a strong focus on coordination throughout. By working closely with stakeholders and planning around key constraints, we were able to keep disruption down while maintaining a smooth and efficient delivery.“
Martyn Crocker
Operations Director

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Value: Multi Million
Diameter: 160mm to 89mm ducts
Duration: 25 months

132kV Energy to Waste Connection

The client required the design, installation, and commissioning of a new 132kV electrical supply system to support energy recovery operations in Belvedere, Dartford.

THE CHALLENGES

The tidal location of the river created a significant flood risk and required careful environmental planning. Complex signal structures on constrained bridge crossings introduced additional engineering and approval challenges, while the proximity to a dual carriageway demanded strict traffic management. The site’s ecological sensitivity, including nesting birds and protected wildlife, limited construction activities, alongside the need to account for structural load and thermal expansion. The exposed installation also presented risks of vandalism and unauthorised access.

WHAT WE DELIVERED

  • Special Engineering Difficulties (SED) included constrained bridge crossings requiring Horizontal Directional Drilling (HDD) beneath roads
  • Potential for flooding due to the river’s tidal nature necessitated placing the pipe bridge above the bridge soffit and within the protection of the Thames Estuary flood defences. Polytetrafluoroethylene (PTFE) sliding bearings and expansion joints were used to accommodate thermal and structural movement without compromising flood resilience

10.6km

cable route

132kV

Electrical supply system

160mm to 89mm

Ducts

 

 

specialisms used

  • Installation
  • Commissioning of high-voltage
  • Bridge crossings
  • HDD (Horizontal Directional Drilling)
  • Diamond coring
“This project brought together complex engineering and environmental considerations in a highly constrained location. Through detailed planning and close coordination, we were able to deliver a compliant and resilient 132kV connection while minimising disruption and ensuring long-term reliability.“
Macc Flynn
Client Project lead