HV Cable Setting Out Point, Route Marking & Route Survey: A Project Manager’s Guide for Renewable Energy Integration

As the renewable energy sector accelerates across the globe, the integration of high-voltage (HV) cables becomes pivotal for connecting solar farms, wind energy systems, and battery energy storage systems (BESS) to AIS (Air Insulated Substations) and GIS (Gas Insulated Substations).

This integration not only demands technological precision but also regulatory compliance, particularly under CDM 2015 (Construction Design and Management Regulations) and HASAWA 1974 (Health and Safety at Work etc. Act).

As a Project Manager or Planner, understanding the criticality of HV Cable Setting Out Points, Route Marking, and Route Survey is essential to ensure safe, efficient, and regulation-compliant project delivery. These pre-construction tasks are foundational in mitigating risks, enhancing power quality, enabling maintainability, and ensuring grid code compliance. I shall discuss this in brief in the following sections below.

A. The Foundation: HV Cable Route Survey and Setting Out Points

The first and foremost step in the successful execution of an HV cable project is conducting a comprehensive route survey.

This survey is not just a formality—it is a risk control measure, a project planning tool, and a compliance necessity.        

What is a Route Survey?

A route survey identifies the physical, environmental, and regulatory constraints of the proposed cable path.

It involves detailed inspection of the ground, topographical data collection, and utility detection using tools such as Ground Penetrating Radar (GPR), GPS mapping, and GIS integration. The result is a well-defined cable route that is safe, accessible, and constructible.

Setting Out Points

Setting Out Points are established based on the route survey.

These physical markers guide trench excavation crews to follow the approved cable route accurately. Any deviation from these points could compromise the integrity of existing underground services, jeopardize safety, or result in regulatory non-compliance.

These markers should be clearly visible and placed in coordination with local authorities, utility providers, and environmental considerations.        

2. Route Marking: Visibility and Compliance

Following the setting out, route marking provides on-ground visibility to guide construction teams.

Painted lines, pegs, flags, or temporary signage are used to indicate the trench path, depth requirements, and crossing points. This is particularly vital in congested urban settings or around critical infrastructure.

Key Route Marking Considerations

• Avoidance of Existing Utilities: Cables must not interfere with existing gas, water, telecom, or power lines. Accurate route marking helps avoid costly and dangerous utility strikes.
• Access for Maintenance: Straight cable paths with accessible entry points are essential. Avoid sharp bends or congested areas that may complicate future maintenance.
• Offset from Drains and Property Lines: For LV cables especially, routes should steer clear of drains and property lines. HV cables are better positioned close to kerb lines, ensuring separation.
• Voltage Separation: Use separate trenches for different voltage levels. If space is restricted, position lower voltage cables above higher voltage cables. Maintain a 600 mm horizontal and vertical gap between power and communication cables.
• Environmental Compliance: Avoid ecologically sensitive areas and ensure no protected zones are encroached upon.

3. Regulatory Framework: CDM 2015 & HASAWA 1974

3.1. CDM 2015: Safe Construction from Design to Delivery

Under CDM 2015, once a design is Issued for Construction (IFC) and approved by the client, the Principal Contractor assumes legal responsibility for executing the work safely and efficiently.

Key duties under CDM 2015 include:

• Ensuring all risks are assessed and mitigated.
• Coordinating with designers to avoid foreseeable hazards.
• Ensuring proper communication among all parties—contractors, designers, and clients.
• Making sure competent personnel are assigned to each activity.
• Maintaining updated documentation including the Construction Phase Plan and Health & Safety File.

The Route Survey and Marking processes align directly with these responsibilities, as they are the first lines of defense against construction hazards.

3.2 HASAWA 1974: Overarching Safety Compliance

The Health and Safety at Work etc. Act 1974 (HASAWA) mandates employers and contractors to ensure the safety of workers and the public during all phases of construction. For HV cable installations, this translates into:

• Safe trenching techniques.
• Avoiding utility strikes.
• Controlling exposure to electromagnetic fields and trip hazards.
• Managing traffic and pedestrian flow where road crossings occur.

By integrating HASAWA obligations with project planning tools (e.g., risk assessments, method statements), project managers reinforce a safety-first culture on-site.

4. Renewable Integration and Trenching Strategy

Trenching for cable laying is a high-risk activity that becomes more complex when integrating renewable energy sources. Wind, solar, and BESS assets often lie in remote, environmentally sensitive areas, making trench routing and execution a logistical and environmental challenge.

Key Pre-Construction Considerations

• Soil Type and Topography: Understanding soil composition is critical for trench depth and width calculations, particularly for areas near wind farms or solar plants with varying ground conditions.
• Drainage and Water Tables: Trenching should avoid flood-prone zones and high water tables that may compromise cable insulation or require dewatering.
• Traffic and Road Crossings: For urban or peri-urban installations, road crossings must be coordinated with councils and include traffic management plans.
• Substation Entry Points: For both AIS and GIS substations, cable entries must comply with design clearances, grounding systems, and thermal dissipation needs.

5. Project Planning & Power Quality Impact

From a planning and scheduling perspective, early identification of route issues allows for proactive mitigation, which significantly improves delivery timelines and reduces costs.

Planning software like Primavera P6 should integrate survey findings and trenching strategies into early-stage Gantt charts, linking them with procurement schedules and resource allocation.

Power Quality Considerations

Improper trenching or poorly planned routes can lead to:

• Voltage drops due to excessive cable lengths or poor jointing.
• Harmonic interference when power and communication cables are too close.
• Earth faults from poor insulation due to water ingress or cable clash.
• Thermal overload if cables are bundled too tightly or lack ventilation space.

By ensuring accurate setting out, marking, and routing, these issues can be avoided, ensuring grid code compliance and long-term asset reliability.

6. The Strategic Value of Route Surveys and Marking

In the context of renewable energy projects, the detailed planning of HV cable routes is far more than a technical requirement—it's a strategic necessity.

Whether connecting a 100 MW solar farm or upgrading a GIS substation for new wind generation, cable route planning ensures that projects are safe, compliant, efficient, and sustainable.

A robust Route Survey and Marking process aligned with CDM 2015 and HASAWA 1974 provides:

• Safer construction environments.
• Lower risk of rework and utility conflicts.
• Improved power quality and operational reliability.
• Easier maintenance and lifecycle management.

This post reflects my personal knowledge and is shared for educational purposes only.

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