Your essential, step-by-step guide to solar panel installation, with a focus on the critical importance of correct torque for optimal performance and safety.

Solar power is becoming increasingly popular and affordable for generating more eco-friendly energy. Drawing power from the sun, solar panels have made their mark as a clean, green source of electricity. This means that while powering your home, you will also reduce your carbon footprint and contribute to a more sustainable future.

This guide provides clear, step-by-step instructions for successfully installing solar panels. It also provides additional insights into tools and techniques for ensuring a secure and efficient installation process.
 

Why choose solar panels?

Solar panels are a cornerstone of the world’s transition to renewable energy. By offering your clients the benefits of solar power, you contribute to a cleaner environment and provide them with a dependable energy solution.

Key benefits include:

• Sustainability: Solar panels help reduce carbon emissions by replacing grid electricity (often generated from fossil fuels) with renewable energy.
• Enhanced property value: Homes and businesses with solar installations often see increased resale value.
• Cost savings: Solar energy can cut electricity bills by up to 50% (1) with some sources suggesting bills can even be slashed by up to 70% (2) offering both residential and business owner clients long term financial benefits.
• Low maintenance: With minimal upkeep, solar panels have delivered reliable performance for decades.
• Energy independence: Solar installations reduce reliance on the grid, ensuring energy availability even during outages.

 
Alongside this, solar panels typically have a lifespan of between 25 and 30 years (3), making them a solid long-term investment for your home. Their life span can even be extended by making sure they are kept clean, well-maintained and out of the shade.

As a professional installer, part of your role is critical in maximising these benefits through proper design, installation and maintenance practices. The expertise you bring to the table as a professional installer ensures clients receive the highest standard of service.

Some of the key advantages of professional solar panel installation include:

• Safety and Compliance: Adherence to industry regulations and safety standards minimises risks during and after installation.
• Optimal Performance: Proper positioning, angling and securing of panels maximise energy output and system longevity.
• Expert Advice: Clients rely on your knowledge to navigate government incentives, select suitable equipment and an optimised system design.

 
Tools of the trade
For a professional installation, precision is key. Panels are often secured in place with power tools however equipment like high-quality torque testers and digital torque wrenches are indispensable for ensuring all tools are delivering the correct torque and that fasteners are tightened exactly to the manufacturer’s specifications. Accurate torque application prevents damage from over-tightening and ensures the long-term stability of the system.

Legal and structural prerequisites
Even for the most experienced installers, it’s essential to work with qualified electricians for system wiring and professional surveyors to confirm the structural integrity of roofs. These measures not only comply with regulations but also protect clients’ investments in solar energy systems.
 
(1) https://www.greenmatch.co.uk/solar-energy/solar-panels/electricity-bills
(2) https://www.greenmatch.co.uk/blog/2014/08/what-is-the-installation-cost-for-solar-panels
(3) https://www.greenmatch.co.uk/blog/2015/01/the-lifespan-of-solar-panels
 

A Step-by-Step Installation Process

1. Preparation & Planning

System Design
Design a system that meets the client’s energy needs while adhering to local regulations and site constraints. With that in mind, you should consider:

• Energy Consumption: Analyse the client’s historical energy usage to determine the required system size.
• Panel Layout: Plan the arrangement of panels to maximise energy efficiency while considering aesthetic and structural factors.
• Inverter Selection: Choose the appropriate inverter type (string, micro, or hybrid) based on system complexity and client requirements.

Site Assessment
Before beginning any installation, conduct a thorough site assessment to determine the suitability of the location for solar panels. Key considerations include:

• Structural Integrity: Inspect the roof to ensure it can support the weight of the solar panels and mounting system. Engage a structural engineer if necessary.
• Sunlight Exposure: Evaluate shading patterns and orientation to identify the optimal placement for panels. South-facing roofs with minimal shading are ideal in the Northern Hemisphere.
• Roof Condition: Ensure the roof is in good condition and does not require repairs or replacing in the near future.

Permits and Compliance
Ensure all necessary permits are obtained before installation. Familiarise yourself with local building codes, zoning regulations and utility interconnection requirements.
 

Tools & Equipment
Prepare the necessary tools, including:

• Specialised tools for mounting systems and electrical connections.
• Multimeters for electrical testing.
• Safety harnesses and PPE for working at heights.
• Torque testers and torque controlled fastening tools for precise tightening of bolts and fasteners.

2. Setting up Scaffolding and Safety Measures

Scaffolding Installation
Scaffolding provides a safe and stable platform for working at heights during installation. Follow these steps:

• Assemble scaffolding according to manufacturer instructions, ensuring it complies with local safety standards.
• Secure the scaffolding to the building to prevent movement.
• Install guardrails and toe boards for additional safety.

Safety Protocols
Adhere to strict safety protocols to protect your team and the property:

• Conduct a safety briefing before starting work.
• Use fall protection equipment, including harnesses and anchor points.
• Ensure all tools are secure to prevent falling hazards.
• Maintain a clean and organised work site to reduce trip hazards.

3. Installing the Mounting System

The mounting system provides the foundation for the solar panels. Proper installation is critical for durability and performance.

Marking & Measuring

• Use a chalk line to mark the location of the roof rafters.
• Measure and mark the positions for mounting brackets, ensuring even spacing and alignment.

Attaching Mounting Brackets

• Drill pilot holes into the rafters to prevent splitting.
• Secure the brackets using lag bolts and a digital torque wrench to achieve manufacturer-recommended torque levels.

Installing Rails

• Attach rails to the mounting brackets, ensuring they are level and aligned.
• Use a spirit level and adjust as needed to maintain a flat surface for panel installation.
• Tighten rail fasteners with a tool with torque control for a secure fit.

4. Panel Installation

Once the mounting system is in place, the solar panels can be installed.

Positioning the Panels

• Place panels onto the rails without securing them initially.
• Adjust the panels to achieve proper alignment and spacing.

Securing the Panels

• Use clamps to secure the panels to the rails.
• Tighten clamps with a torque adjustment capability to prevent over-tightening or under-tightening.
• Double-check all fasteners for stability.

Cable Management

• Route panel cables neatly along the rails using cable clips or ties.
• Avoid sharp bends or excessive tension in the cables.

5. Electrical Wiring

Electrical wiring is a critical step that must be performed with precision and adherence to safety standards.

Wiring Configurations

• Series wiring: Connect the positive terminal of one panel to the negative terminal of the next to increase voltage.
• Parallel wiring: Connect all positive terminals together and all negative terminals together to increase current.

Connection to the Inverter

• MC4 connectors are used for secure and weatherproof connections.
• Route wires to the inverter location, avoiding areas prone to physical damage.
• Label all wires for easy identification and maintenance.

Grounding

• Install a grounding system to protect against electrical faults.
• Connect all metal components of the system to the grounding conductor.
• Test the grounding system for continuity and resistance.

6. Inverter Installation

The inverter is the heart of the solar panel system, converting DC electricity from the panels into AC electricity for use.

Mounting the Inverter

• Install the inverter on a wall near the main electrical panel.
• Ensure the location is shaded and well-ventilated to prevent overheating.

Connecting the Inverter

• Connect the DC input wires from the panels to the inverter.
• Connect the AC output wires to the main electrical panel.
• Install surge protection devices to safeguard the inverter from voltage spikes.

Configuring the Inverter

• Program the inverter settings according to the system design.
• Test the inverter’s functionality to ensure it is operating correctly.

Battery integration (optional)
Adding a battery storage system enhances energy independence and efficiency.
 

Battery Selection

• Choose a battery that matches the system’s voltage and capacity requirements.
• Consider lithium-ion batteries for their efficiency and lifespan.

Installing the Battery

• Mount the battery in a well-ventilated area away from direct sunlight.
• Connect the battery to the inverter using appropriately sized cables.
• Secure all connections with a torque-controlled fastening tool.

Testing and Configuration

• Test the battery system to ensure proper charging and discharging.
• Configure settings for time-of-use optimisation if applicable.

7. System Testing and Commissioning

Before a solar PV installation takes place, a few things must be considered. Local energy network suppliers or distributors need to be notified to allow them to assess if the local electricity network can handle the additional energy being exported back to the grid (4). This process varies depending on the size of the installation.

For example, in the UK installations under 16A can be reported post-installation and within 28 days of completion. Larger solar PV installations and systems above 16A must be communicated prior to installation, to allow time for necessary assessments and calculations.

Before the actual system is then handed over to the client, the installer must conduct comprehensive testing and commissioning:

Inspection

• Inspect all components for proper installation and alignment.
• Verify that all fasteners are tightened to the correct torque specifications.

Electrical Testing

• Measure the open-circuit voltage (VOC) and short-circuit current (ISC) of the panels.
• Test the inverter’s output to ensure it matches system specifications.
• Check grounding continuity and insulation resistance.

Performance Testing

• Monitor the system’s performance under sunlight to verify energy production.
• Use monitoring software to check for any faults or inefficiencies.

(4) https://www.gov.uk/government/publications/register-energy-devices-in-homes-or-small-businesses-guidance-for-device-owners-and-installation-contractors/register-energy-devices-in-homes-or-small-businesses-guidance-for-device-owners-and-installation-contractors
 

8. Client Handover and Documentation

At the completion of a solar PV installation, the installer must provide the client with all necessary documentation to ensure they can effectively operate and maintain their system. This includes all relevant certifications.

For example, in the UK solar installers that are MCS accredited (Microgeneration Certification Scheme), must supply an MCS certificate within 10 days of the system being commissioned (5).

This gives the homeowner confirmation that the proper tools, equipment and workmanship have been used during the installation. This certificate serves as valuable proof of quality, particularly when selling the property in the future.

Additionally, an accredited installation is often required to qualify for export tariffs, making the certificate an essential component of the handover process.

Client Training

• Demonstrate how to monitor system performance using the inverter or monitoring software.
• Explain basic maintenance tasks, such as cleaning panels and inspecting connections.

Documentation
Provide a comprehensive handover package, including:

• System design and layout drawings.
• Warranty information for all components.
• Maintenance schedule and contact details for support.

9. Post-installation Maintenance and Support

Offer ongoing support to ensure the system continues to operate efficiently.

Scheduled Maintenance

• Conduct periodic inspections to check for loose connections, damaged cables, or dirt accumulation on panels.
• Re-tighten fasteners using a validated torque-controlled tightening tool.

Performance Monitoring

• Use remote monitoring tools to track system performance and identify issues early.
• Provide clients with regular performance reports.

Best Practices for:

Professional Installers
If you’re a professional solar panel installer, you should follow the below best practices:
 
1. Adhere to manufacturer guidelines: Follow the installation instructions provided by manufacturers to ensure warranty compliance.
2. Use high-quality tools: Invest in precision tools and methods of testing the torque applied e.g. digital torque wrenches or torque testers, to achieve consistent and accurate results.
3. Prioritise safety: Implement rigorous safety protocols to protect your team and the property.
4. Stay informed: Keep up-to-date with industry advancements, regulations and best practices.
5. Communicate clearly: Maintain transparent communication with clients to manage expectations and build trust.
 

Long-term System Performance
Installers play a key role in ensuring the system’s long-term success. Recommendations for clients include:
 
Routine Maintenance: Regularly clean panels to remove dirt and debris that can reduce efficiency.
Periodic Inspections: Re-torque fasteners and inspect components to maintain stability and performance.
Energy Monitoring: Encourage clients to use monitoring tools to track system performance and detect issues early.
 

The Importance of Torque in Solar Installations

Torque management is a critical aspect of professional solar panel installation. Improperly tightened fasteners can compromise system integrity, leading to costly repairs or failures.

When using an impact wrench or other power tools during installation, it’s essential to use a torque tester to test, calibrate and monitor torque applications. For more critical fasteners, consider using a digital torque wrench to fasten precisely and check the torque.

Key torque applications during the solar panel installation process:
 
Mount Durability: Secure mounts to withstand environmental stresses.
Panel Security: Prevent panel displacement with uniform torque application.
Tool Testing: Ensuring power tools, such as impact wrenches, deliver the correct torque to fasteners.
Electrical Safety: Achieve reliable electrical connections by torquing terminals to specified values.
Scaffolding Stability: Tighten scaffolding bolts to exact torque values, ensuring worker safety.
 

By leveraging your expertise, precision tools and adherence to best practices, you can deliver installations that provide reliable, sustainable energy for years to come. Your role as a professional installer is pivotal in driving the adoption of renewable energy and supporting the UK’s transition to a greener future.

Having the right tools to complete the job safely is a must. At Crane Electronics, we have a range of torque testers and digital torque wrenches that will help to ensure compliance with ever-evolving regulations, optimise health and safety, while maximising long-term solar panel performance.

To download the PDF version of above installation guide please visit www.crane-electronics.com/solar-panel-installation-guide. For more information about our products and solutions, please get in touch with us using the form below.