The flat is allowed 4.6 kW. A winter evening needs 6.7.
With the floor heating on and dinner cooking, the limiter cuts power to the whole flat. Switch things on and off to see where the limit is.
The figures are from the building's electrical design, except the ones marked as estimates. The 3 kW for the living-room floor is the value set on its thermostat. Floor heating switches fully on and fully off, so the power cuts look random: they come when the floor starts heating while someone is cooking.
Where 4.6 kW comes from
The building's electrical design from November 2020 (glavni projekt, sheet 11.1) added up everything in the flat and assumed that about a quarter of it would ever run at once.
The list behind that sum has no living-room floor heating. The only floor heating in the design is the bathroom, drawn at 0.35 kW (the installed bathroom floor is 450 W). The 3 kW living-room floor came later, and the connection stayed the same size.
The evidence
Photos of the flat's panel, the building's electrical design and the living-room thermostat.
What is established, and what still needs a check
Established from the photos
- The limiter is 20 A. The photo shows L20, and the design says "limitator 20A".
- The design sizes the connection at 4.589 kW, using a simultaneity factor of 0.26.
- The design has one floor-heating circuit: bathroom, 0.35 kW on paper (450 W installed).
- The living-room thermostat is set up for a 3000 W floor.
- The flat's main switch and RCD are rated 40 A, and the feed cable is 3×10 mm² according to the design.
Still to check
- The real power of the living-room floor. The 3000 W was typed in when the thermostat was installed. To measure it, switch off everything except that floor and read the electricity meter.
- Which breaker feeds it. The panel has the same 20 breakers as the design, so the floor sits on an existing or spare circuit. F01.18 and F01.20 are outputs with no appliance named.
- Whether the building can give the flat more power. HEP ODS decides that when it answers the request.
- Exact appliance figures. The simulator uses the design's numbers, or estimates where marked. The rating plates have the exact ones.
The fix: a bigger connection
The owner asks HEP ODS to raise the connection (povećanje priključne snage), and HEP swaps the limiter. The limiter is sealed and nobody else may touch it.
How the cost is worked out: the added kW × 193.00 €/kW, which is HEP ODS's unit price for a low-voltage connection, plus 25% VAT. That gives 277.44 € for 25 A and 665.85 € for 32 A. These are estimates; the binding amount is in HEP's offer. "Winter evening" means both floors heating and the hob on all zones, 6.7 kW.
How the request goes
- The owner files a request for an electricity approval (Zahtjev za izdavanje EES, form PM 1.2.1) and ticks "povećanje priključne snage". HEP recommends its Moja mreža app.
- HEP ODS issues the approval together with an offer and a new network-use contract.
- The owner pays the fee and returns the signed contract.
- HEP ODS replaces the limiter.
An electrician should confirm on site that the flat's wiring suits the new current. On paper it does: the design shows a 3×10 mm² feed, and the main switch and RCD are rated 40 A.
Until then
- Set the thermostat schedules so the floors do not heat while someone cooks.
- Run the boiler at night.
- An electrician can fit a priority relay that switches the floor heating off while the hob is drawing current.
These reduce the power cuts. The flat still cannot heat and cook at the same time.