Introduction Installing a solar PV system involves more than just the panels on your roof. Each system is a carefully designed assembly of components that work together to generate, convert, store, and manage solar energy efficiently and safely. In this post, we’ll break down all the essential parts that make up a complete solar PV system.
What makes up a complete solar PV system
Solar Panels
The heart of the system. These convert sunlight into direct current (DC) electricity.
- Premium panels are constructed of monocrystalline silicon and in Ireland most commonly available in 1762mm x 1134mm x 22mm. They weigh 22kg and ideal weight and size for installation on pitched roofs and carry a 25 year warranty.
- Approx. 35-40V, 12.5 – 16A) and can be roof, ballast or ground mounted in portrait or landscape orientation, depending on the available space.
Key Fact: Panels are grouped in series to form a “string,” allowing voltage to accumulate while current remains constant.
Mounting Structure
Roof Hooks & DC Rails:
Secure the solar panels to your roof with a minimum 10° pitch for self cleaning.
- Tile Hooks are fitted to tiled roofs with DC Rails fitted – this allows the solar panels to be clamped in place. The tiles are physically ground for fitment of the slim roof hook. This does not alter weather tightness and is as good after as was before, no change.
- Slate Hooks are fitted to slate roofs using a flashing to maintain weather tightness. Modern flashings are a game changer with installation in two pieces creating a sandwich seal that does not require the removal of slates. This results in less disruption and a reliable long term seal once installed using the correct method and care.
Flat Roof Ballast Frames:
Used when a pitched roof is unavailable or a poorer choice.
- These are fixed installations with 10° or 15° Pitch options. 15° preferred to optimise performance, 10° preferred when less space available (smaller shadow cast).
- South Ascent frames face same direction and require a gap between rows to deal with shadow projected from panel at front. Usually 10° Pitch to minimise shadow length.
- East/West Ascent frames are shaped in an A. These usually are installed in a 15° Pitch.
- Ballast frames use regular concrete blocks (20kg each) with a minimum of 2-3 blocks per panel, higher wind areas will opt for 3-4, to be sure.
Ground Mount Frames:
Used when roof space isn’t a viable option, allowing flexibility in orientation and pitch. Typically these frames are fitted direct to ground.
- Concrete base structure fitted to bolt frames directly.
- Frames usually stand well clear of the ground to avoid foliage growth and have portrait or landscape options formats to fit solar panels.
Pro Tip: For durability and weather resistance, anodised aluminium or stainless steel are the material of choice.
DC Cabling
High-quality, double-insulated cables (4mm² or 6mm² options) to transport DC electricity from the panels to the inverter. Moontree uses 6mm² for lower resistance and future-proofing.
Fire-Shunt Automatic Isolation Switch
This solenoid device provides emergency DC isolation. It’s a required safety feature and must be installed within 1.5 metres of the point where DC cables enter the building.
- These are available in 3 sizes normally – 4Pole, 10Pole and 20Pole.
- Each string requires 2Pole, so that covers – 2 String, 5 String and 10 String systems.
- Once the Fire-Shunt is energised by AC Power the system will power on and the solenoid switch engages. When AC power is removed it safely disconnects the Strings.
- DC Strings carry 600V DC, Commercial carry 1000V DC, Utility can carry 1500V DC.
Pro Tip: DC Electricity can Arc, so the fire-switch uses a solenoid switch as a double measure to ensure no arcing of energy is possible once it is powered down.
DC & AC Isolator Switches
Allows manual disconnection of the system:
- DC Isolator: Disconnects power from panels to inverter
- AC Isolator: Disconnects inverter from the main fuseboard & powers down the Fire-shunt(s)
Inverter
Converts the DC power into alternating current (AC), suitable for use in your home or business and ready to export. Inverters can be:
- String: For basic conversion
- Hybrid: For use with battery storage
Inverters also communicate with monitoring apps and connect to your router for updates and data logging.
Battery Storage (Optional)
Batterys Store excess solar energy for use later. Stackable lithium-ion batteries with built-in Battery Management Systems (BMS) are most common. Brands like SIGENERGY, SAJ and Dyness are known for compact design and high reliability.
AC Box for Inverter
Includes a mix of:
- MCBs (trip switches)
- RCDs (safety breakers)
- RCBO’s (Combined). 100ma is now acceptable for both Domestic & Commercial, this reduces problematic tripping occurrences.
- Surge protection
- Solar meter for tracking energy flow
Pro Tip: By keeping the Solar system circuit protection separate from the main fuse board, this helps identifying issues and isolating them. Its black & white. This can be done by keeping to a separate row on the main fuse board or preferably fitting a separate AC Box or Gateway.
Monitoring System
Inverters connect to a portal or app via Wi-Fi or cable, allowing live performance tracking, updates, and system diagnostics.
Accessories
- EV Chargers (e.g., myenergi Zappi, Sigenergy AC & DC Chargers)
- Heating Diverters (e.g., myenergi Eddi, Sigenergy Gateway)
Conclusion
A solar PV system is only as strong as the components used and how well they work together. At Moontree Solar, we carefully select, design, and install systems using proven, high-quality components—ensuring every installation is safe, reliable, and built to perform.
Want to understand how these parts fit into a design for your property? Reach out for a custom proposal today.
