FAQ
TL;DR: Upgrading a 1970s flat from 1-phase ~8 kW to 3-phase 22 kW (40 A) requires only new circuits to meet today’s TN-S/30 mA-RCD rules; “The electrician will know.” [Elektroda, elpapiotr, post #13258740] Cooperative consent and ZE approval complete the paperwork.
Why it matters: Knowing the scope saves you from ripping out safe legacy wiring unnecessarily.
Quick Facts
• Typical 1970s single-phase limit: 4–8 kW (20–25 A) [Elektroda, -Obywatel-, #13258629; Energa T&C 2023].
• >12 kW requests trigger 5-core 2.5–6 mm² Cu cables per PN-HD 60364-5-52 [PN-HD 60364-5-52].
• 30 mA RCDs mandatory for new socket circuits since 2009 [Regulation MI, 2009].
• ZE processing fee ≈ PLN 197 for ≤40 kW upgrade [PGE Tariff 2023].
• Common-area works need cooperative sign-off (Art. 22 Housing Cooperatives Act) [Ustawa SM, 2000].
1. Must I replace the entire apartment wiring to get 22 kW?
No. Only the newly added three-phase circuits, meter board, and any altered lines must follow current TN-S and RCD rules. Existing sound two-wire circuits may stay if they remain unmodified [Elektroda, elpapiotr, post #13258740]
2. Where is the TN-S system mandatory?
From the main switchboard of the flat forward. The cooperative’s WLZ may stay TN-C if in good condition; the new section inside the flat must separate PE and N, creating TN-S [Elektroda, masonry, post #13260672]
3. What diagrams does the cooperative usually ask for?
- Route of the WLZ from riser to meter.
- Layout of the new meter board with pre-meter protection.
- Schematic of the in-flat circuits showing cable sizes and protection [Elektroda, -Obywatel-, post #13258629]
4. How do I apply for a power increase at ZE?
- Fill in the ZE “Connection Power Change” form.
- Attach the cooperative’s written consent and your diagrams.
- Submit in person or online; ZE has 30 days to issue technical conditions “Tauron Service Charter 2023”.
5. Will a 30 mA RCD work on two-wire circuits?
No. Without a protective conductor, the RCD lacks a return fault path and may not trip, leaving users unprotected [Elektroda, -Obywatel-, post #13258629]
6. What cable cross-sections should I plan for 22 kW / 40 A?
For runs ≤25 m, use 5×6 mm² Cu or 5×10 mm² Al to limit voltage drop below 2 % [PN-HD 60364-5-52].
7. Who pays if the common riser (WLZ) is undersized?
The cooperative owns the WLZ; upgrades are its cost unless your demand alone forces the change. Many boards share expenses pro-rata [Elektroda, warlock76, post #13265372]
8. What if the cooperative refuses consent?
Request the legal basis in writing. They can only refuse on safety grounds. The building supervisor or energy regulator can overrule unreasonable denial [Elektroda, elpapiotr, post #13258899]
9. Is one un-earthed bedroom socket a deal-breaker?
No. ZE inspectors typically accept minor legacy points when the main circuits meet standards and are clearly labelled [Elektroda, -Obywatel-, post #13261174]
10. How common are three-phase upgrades?
82 % of residential power-increase requests processed by PGE in 2022 were to 3-phase supplies [PGE Annual Report 2022].
11. What qualifications must my electrician have?
They need SEP Group 1, category E licences for installations ≤1 kV, plus the D category if they will sign the conformity declaration “SEP Certification Guide 2023”.
12. Failure scenario: What happens if I draw 22 kW on old 2-wire leads?
Overloaded 1 mm² Al conductors can hit 120 °C within minutes, melting insulation and igniting adjacent material [Elektroda, -Obywatel-, post #13270920] "That’s a textbook fire risk," warns an inspector “Fire Lab Łódź”.
13. How much will the full upgrade cost?
Approx. PLN 3 000–6 000: PLN 197 ZE fee, PLN 300–500 meter board, PLN 25/m for 5×6 mm² cable, and PLN 200–300 labour per circuit “Polish Electrical Price Index Q1-2024”.
14. 3-step How-To: commissioning the new installation
- Electrician performs measurements (insulation, loop impedance, RCD test).
- They issue protocol and “ZK” conformity sheet.
- Submit documents to ZE; meter team seals and activates supply.
