Photovoltaic & electrical installation – Professional PV system connection
Photovoltaic systems are sustainable and economical. However, the electrical installation is complex. This guide explains DC wiring, inverters, storage and grid connection.
💰 Profitability
A 10 kWp PV system generates approx. 9,000-10,000 kWh/year. At 30 ct/kWh this saves approx. 2,700-3,000 € annually.
Components of a PV system – Overview
Solar modules
Convert sunlight into direct current (DC). Typical power: 350-450 Wp.
Inverter
Converts DC current into grid-compliant AC alternating current (230V/400V).
Battery storage (optional)
Stores surplus power for evening/night hours. Increases self-consumption to 60-80%.
Bidirectional meter
Measures power purchase and feed-in. Installed by grid operator.
Electrical requirements of PV installation
DC wiring (solar modules → inverter)
DC voltages up to 1000V require special caution and special material.
- UV-resistant solar cables (H1Z2Z2-K 4 mm² or 6 mm²)
- MC4 connectors for secure connections
- DC disconnect point on roof and inverter
AC connection (inverter → grid)
The inverter feeds into the house grid. AC wiring must be sized for full feed-in power.
| Inverter power | Connection type | Cable cross-section |
|---|---|---|
| bis 5 kW | 1-phasig, 230V | 5x 6 mm² |
| 5-15 kW | 3-phasig, 400V | 5x 10 mm² |
| über 15 kW | 3-phasig, 400V | 5x 16 mm² oder größer |
Surge protection and earthing
PV systems are at risk of lightning. Multi-stage surge protection concept (Type 1 + Type 2) is mandatory.
Grid connection and registration with network operator
Step 1: Grid compatibility check
Register PV system with network operator. Check if grid can handle feed-in power.
Step 2: Request bidirectional meter
Old electricity meter is replaced by bidirectional meter.
Step 3: Commissioning and declaration of conformity
System checked by electrician. Test report transmitted to network operator.
Step 4: Registration in master data register
Every PV system must be registered with the federal network agency – otherwise feed-in tariff expires!
Battery storage: Is retrofitting worthwhile?
A battery storage increases self-consumption from 30% to 60-80%.
Advantages of storage
- Higher self-consumption: Use solar power in the evening too
- Less grid purchase: Electricity bill decreases (500-1,000 €/year)
- Emergency power capability (optional)
To consider
- Storage costs 6,000-12,000 €, payback 10-15 years
- Service life: approx. 10-15 years
- Space requirement: approx. 1 m², ventilation needed
Monitoring and maintenance of PV system
Use monitoring system
Regularly check yield and error messages.
Module cleaning every 2-3 years
Cleaning can bring 5-10% additional yield.
Take out maintenance contract
Annual check: visual inspection, connections, insulation measurement.
Conclusion: PV installation requires expertise – but it's worthwhile
A PV system generates clean electricity for 25-30 years. Installation is complex and requires expertise.
Important: PV systems must be registered in the master data register!