Many solar problems originate in design and workmanship rather than the panel itself. A disciplined survey, coordinated engineering, approved materials and documented commissioning prevent lost generation, water leakage, nuisance trips and unsafe faults.
Key takeaways
- Do not size a project from bill value alone.
- Complete shade and structural checks before layout approval.
- Verify every string against inverter limits.
- Commission and document the full system.
Poor survey and layout decisions
Ignoring seasonal shade, access paths, roof drainage, parapets, equipment clearances and future obstructions can reduce output and make maintenance unsafe. Layout drawings should use actual roof dimensions and module sizes. Structural attachment and waterproofing details should be agreed before installation.
- Survey shade at different times and seasons.
- Keep required setbacks and walkways.
- Protect drainage and waterproofing.
- Confirm structure and wind loading.
Incorrect electrical design
Strings outside the inverter MPPT range, excessive input current, underrated isolators and poor breaker coordination can cause faults or lost production. AC and DC voltage drop should be checked, and maximum PV voltage should use the lowest expected temperature. Equipment ratings must match the actual circuit.
- Check Voc, Vmp, Isc and MPPT limits.
- Use DC-rated switching and protection.
- Calculate cable ampacity and voltage drop.
- Verify breaking capacity and selectivity.
Cable and connector workmanship
Loose cables, incorrect crimping, mixed connectors, tight bend radius and unsupported roof-level plugs can lead to water ingress, heating or arcing. Installation teams should use approved tools and inspection records, then secure cables clear of sharp edges and water paths.
- Use matched connector systems.
- Verify crimp quality and engagement.
- Support and protect cable routes.
- Apply specified terminal torque.
Weak commissioning and handover
Energising without polarity, insulation, continuity, protection and functional checks leaves hidden defects. Handover should include as-built drawings, datasheets, warranties, test results, monitoring access, shutdown instructions and maintenance guidance. The owner should know who responds to alarms and warranty claims.
- Complete documented pre-energisation checks.
- Record initial string and inverter readings.
- Train the owner on safe operation.
- Define service and escalation contacts.
Frequently asked questions
What is the most common cause of low solar generation?
Shade, soiling, layout mismatch, inverter downtime and electrical defects are common; monitoring and inspection are needed to identify the actual cause.
Can panels be installed on any roof?
No. Structural capacity, waterproofing, access, fire safety, wind loading and usable unshaded area must be assessed.
What documents should I receive?
Obtain approved drawings, datasheets, warranties, test records, approvals, monitoring details and operation and maintenance guidance.
Turn guidance into a practical system plan
Use Spectra’s engineering calculators for a preliminary estimate, then request technical verification before purchase or installation.