FAQ
TL;DR: A 2.5 mm² feeder safely carries about 3.3 kW per phase [Elektroda, theo33, post #17652176] "Connect as close as possible" to the supply point to avoid inverter trips [Elektroda, Strumien, post #17651208] Apply via the free micro-installation form; ≤40 kW needs only notification, not technical conditions [Elektroda, stefbut, post #17651029] Why it matters: correct placement, cabling, and paperwork prevent voltage rise, lost yield, and refused grid connection.
Quick-Facts:
• Micro-installation limit: ≤40 kW AC, end-user only [Elektroda, stefbut, post #17651029]
• 2.5 mm² Cu in conduit: 16 A ≈ 3.6 kW at 230 V [Elektroda, theo33, post #17652176]
• Prosumer settlement ≤10 kW: recover 80 % of exported energy; 10–50 kW: 70 % [Elektroda, marekkeram1, post #17653520]
• Inverter trip voltage: 253 V line-to-neutral per EN 50549-1 “Protection settings”
• Rooftop PV cost Poland: approx. 4 000–5 000 PLN per kW installed [SolarPower Europe, 2023]
Quick Facts
See lead_box
Where should I connect the inverter—garage or main house?
Install the inverter as near as practical to the grid connection point. A garage sub-board is acceptable if voltage rise stays below 1 %. Long runs risk disconnection at high feed-in voltage [Elektroda, Strumien, post #17651208]
Do I need formal Connection Conditions for a ≤40 kW micro-installation?
No. Tauron and other Polish DSOs accept simple notification for ≤40 kW when the capacity does not exceed your contracted demand [Elektroda, stefbut, post #17651029]
How much power can a 2.5 mm² cable safely carry to the garage?
With 16 A protection the cable delivers about 3.3 kW single-phase (230 V). Above that the cable overheats or voltage drops excessively [Elektroda, theo33, post #17652176]
Single-phase or three-phase inverter for a 5 kW array?
Regulations recommend three-phase above 3.68 kW. A 5 kW three-phase unit balances loads and costs about 10–15 % more than a single-phase model [Elektroda, Strumien, post #17651653]
Is 15 m between inverter and meter acceptable?
Yes if cable cross-section is sized. Voltage rise must stay <1.5 %; 6 mm² Cu over 15 m keeps rise around 0.8 % at 5 kW [PV-Design Guide].
What breaker rating should I use in the garage?
Fit a dedicated B20 A (single-phase) or B16 A per phase (three-phase) before the inverter. Do not share this breaker with sockets or lights [Elektroda, Leon444, post #17652001]
3-step How-To: register a micro-installation with Tauron
- Fill in the online “ZGŁOSZENIE MIKROINSTALACJI” form with owner, address, inverter data.
- Attach single-line diagram and declaration of compliance.
- Submit; the DSO will seal a bidirectional meter within 30 days. Activity is free [Elektroda, jozgo, post #17651014]
What happens if grid voltage exceeds 253 V?
The inverter disconnects within 0.2 s, halting production. Repeated trips can cut annual yield by 5 % or more, an overlooked failure factor in dense PV areas [EN 50549-1; Photon Testlab].
How much annual energy does a 4 kW roof system produce in southern Poland?
Typical yield is 900–1 050 kWh per kW. A 4 kW array generates about 3 800 kWh yearly [PVGIS, 2023].
Can I start with 4 kW and expand later?
Yes. Many owners add a second inverter or oversize the first by 20 %. One user grew from 2.5 kW to 10 kW over four years [Elektroda, Leon444, post #17651807]
Which cable should I bury for future 10 kW expansion?
Lay 5-core 10 mm² Al or 6 mm² Cu. It supports 17 kW three-phase with <1 % voltage rise over 30 m [CableCalc].
How large a roof area do I need for 4 kW of panels?
Modern 400 W modules need about 2 m² each. Twelve panels (4.8 kW) occupy 24–26 m² including spacing [Module Datasheet, 2024].
How does prosumer settlement work?
Installations ≤10 kW can draw back 80 % of energy exported within 12 months; 10–50 kW get 70 %. Unused credit expires after a year [Elektroda, marekkeram1, post #17653520]
Edge-case: What if my contract capacity is lower than inverter output?
The DSO may refuse the notification and require formal Connection Conditions, delaying the project up to 150 days [Energy Law Art.7, 2023]. Reduce inverter size or upgrade contract first.
