Anyone planning to install solar panels, an EV charger, a heat pump, or a serious induction hob runs into the same question early: is my home single-phase or three-phase? Most homeowners don’t know. Most installers will refuse to quote until you tell them. The good news — you can usually figure it out yourself in five minutes, without an electrician, using one of six methods below. We’ve ranked them from most reliable to least. If you’d rather skip the detective work entirely, the free analyzer above reads it straight from your electricity bill in about ten seconds.
Why your home’s phase actually matters
Single-phase: 230 V, simple, dominant in European homes
Single-phase supplies one live wire and one neutral, alternating at 50 Hz, giving you 230 V at every socket. It’s the default for most homes in Spain, France, Italy, the Netherlands, Belgium, and the rest of continental Europe. It comfortably runs an oven, a washing machine, a dishwasher, lights, and a TV simultaneously. Where it starts to feel cramped is when you stack high-power loads: an 11 kW EV charger, an 8 kW heat pump, and a 7 kW induction hob all running together will trip a single-phase setup with anything below about 12 kW of contracted capacity.
Three-phase: 400 V between phases, common in larger homes and small businesses
Three-phase supplies three live wires staggered 120° apart in their AC cycle, plus a neutral. Any single socket still sees 230 V to neutral, but high-power appliances (EV charger, heat pump, workshop motor) can be wired across two phases to receive 400 V — meaning they pull less current per wire for the same kW, reducing heat, voltage drop, and cable cost. Three-phase is the default for buildings with more than about 14 kW of demand, and for homes with workshops or commercial-grade equipment.
Why this matters before you commit to a solar setup or EV charger
Solar inverters come in single-phase and three-phase versions. A three-phase home with a single-phase inverter creates load imbalance (which your distributor may flag) and caps the size of system you can install — about 5 kW per phase is the practical limit on most contracts. EV chargers behave the same way: an 11 kW or 22 kW charger needs three-phase to deliver that speed; on single-phase you’re limited to 7.4 kW. Heat pumps over about 9 kW typically expect three-phase too. Knowing your phase up front avoids buying equipment you can’t plug in.
The six ways to tell
Method 1 — Look at the main circuit breaker (ICP or IGA)
The single most reliable indicator, available to anyone who can see their breaker box without opening it. Spanish homes (and most continental European homes) have a main switch at the top of the breaker panel called the ICP (Interruptor de Control de Potencia) or, in newer setups, the IGA (Interruptor General Automático). It looks like a slightly larger version of a regular breaker switch. Count the toggle positions on it:
- 2 toggles side by side, linked so they move together → single-phase
- 3 or 4 toggles linked together → three-phase
You don’t need to open anything or touch any wires — just look at the front of the panel. This works for over 95% of European homes built in the last thirty years. Don’t try to operate the switch unless you know what you’re doing; flipping the main can be inconvenient at best, dangerous if you have life-critical equipment downstream.
Pro tip if the panel is already open: the incoming wires confirm the same answer — 2 wires (1 live + 1 neutral) means single-phase, 4 wires (3 lives + 1 neutral) means three-phase. Don’t open the panel just for this. The toggle count tells you the same thing without any risk.
Method 2 — Read the technical section of your electricity bill
Open your most recent electricity invoice. Look for a section titled (in Spanish) Datos del suministro, Datos de la instalación, or Datos técnicos. In English-language bills the heading is usually “Supply details”, “Installation details”, or “Technical data”.
Some providers state the phase plainly: “Monofásico” / “Trifásico” / “Single-phase” / “Three-phase”. Iberdrola and Endesa usually do. If yours does, you’re done.
If yours doesn’t state it directly, look at potencia contratada (contracted power capacity). Probabilistic rule of thumb:
- Below 10 kW → almost always single-phase
- 10 to 14.49 kW → could be either; single-phase still dominant
- Above 14.49 kW → almost always three-phase (single-phase tops out at 14.49 kW under current Spanish norms)
This is probabilistic, not proof. If you really need certainty, combine with one of the visual methods.
Method 3 — Check your distribution company’s online portal
Spanish distribution companies (separate from your retailer) maintain online customer portals where you can see every detail about your supply point. Register once with your meter point number (CUPS, printed on every bill), then you’ll find the answer directly:
- Type of installation: monofásica or trifásica
- Contracted power per phase
- Maximum technical capacity available at your address (useful before upgrading)
- Outage history
The Spanish distribution portals are at i-de.es (Iberdrola), e-distribucion.com (Endesa), and naturgydistribucion.com (Naturgy). Look for “Datos del punto de suministro” → “Tipo de suministro” or “Tensión nominal”. “1×230V” = single-phase, “3×400V” = three-phase. In other EU markets equivalent portals exist for Liander/Stedin/Enexis (Netherlands), Enedis (France), your local Stadtwerke or Netzbetreiber (Germany), and E-Redes (Portugal).
Method 4 — Check the meter display
Modern digital electricity meters (Cervantes/CERM in Spain, ZIV, Landis+Gyr, Itron) sometimes show a tiny phase indicator on their LCD screen:
- “1F”, “Mono”, or a single-sine-wave icon → single-phase
- “3F”, “Tri”, or a three-phase icon → three-phase
Older mechanical meters: count the rotating discs visible through the glass cover. One spinning disc → single-phase. Three spinning discs → three-phase.
This method depends on the meter manufacturer and how it’s programmed — some meters don’t surface this info on the default screen. Try pressing the small button on the meter to cycle through screens; you can’t break anything by pressing it.
Method 5 — Find your Electrical Installation Certificate (CIE)
Every legal electrical installation in Spain (and most EU countries) comes with a Certificado de Instalación Eléctrica (CIE) — issued by the electrician when the home was wired or last renovated. In other countries it’s called the Conformity Certificate (Italy), Attestation de Conformité (France), Konformitätsbescheinigung (Germany), or BEE (the Netherlands, partial equivalent). It’s the most authoritative document about your installation. Phase type appears as a voltage notation:
- “1×230V” → single-phase
- “3×400V” or “3×230/400V” → three-phase
Where to find it: closing documents from when you bought or rented the home, the electrical-installation folder kept by the building manager (in apartments), or the records of the electrician who last touched your installation. If you can’t find it, your distributor can issue a copy.
Method 6 — Ask your retailer or distributor
Two different companies are involved in your electricity supply: the retailer (Iberdrola Clientes, Endesa Energía, Naturgy Iberia, Holaluz, etc., who sends your bill) and the distributor (i-DE, e-distribución, UFD/Naturgy, etc., who owns the wires and your meter). Either one knows your phase type from their records.
WhatsApp, app chat, email, or phone with your retailer — they typically answer within minutes. If you’d rather skip the chat, the distributor’s online portal (Method 3 above) is the same answer without waiting on an agent.
Or skip the detective work entirely. Upload your electricity bill to our free analyzer at the top of this page — we’ll read your phase, monthly consumption, and provider in about ten seconds. Jump to the analyzer →
Single-phase vs three-phase: which is better for a home?
Most European homes are single-phase, and that’s usually fine
The vast majority of residential properties in Spain, France, Italy, Belgium, the Netherlands, and Portugal are single-phase. It’s not an inferior setup — it’s the most efficient match for typical home demand. Standard appliances are single-phase. Solar inverters up to 5–6 kW are single-phase. EV chargers up to 7.4 kW (overnight charging, about 36 km of range per hour) are single-phase. Heat pumps up to about 9 kW can be single-phase. If your home demand sits comfortably below 12 kW and you don’t have an industrial use case, single-phase is the right answer and there’s no benefit in upgrading.
When three-phase actually helps you
Reasons that genuinely justify the cost of upgrading:
- EV fast charging at home (11 kW or 22 kW) — three-phase required
- Heat pump over about 9 kW thermal output
- Workshop with welding equipment, machine tools, or air compressors that run on 400 V
- Solar system larger than about 5–6 kW peak combined with battery and EV — a three-phase inverter handles load balance better
- Multiple high-load appliances running simultaneously (sauna + induction + hot tub etc.) — three-phase spreads current evenly
If none of those apply, the cost of upgrading rarely pays back.
What it costs to upgrade (rough ranges)
Switching a single-phase home to three-phase in Spain typically runs €600–€2,500, depending on:
- Distance from your home to the nearest three-phase distribution line (often the biggest cost driver)
- Whether your meter cabinet needs replacement
- Whether your breaker panel needs upgrading (almost always — three-phase needs a wider ICP and additional protections)
- New CIE issued by an authorised electrician (€150–€300)
- Paperwork with your distributor (free in most cases, occasionally a connection fee)
For homes in a building that already has three-phase to the building entry, the internal upgrade can be done in a day. For standalone homes far from a three-phase line, the distributor charges per metre of new cable trench and the cost can balloon.
When you should keep single-phase even if you could afford the upgrade
If your only motivation for going three-phase is “future-proofing” without a specific load that justifies it, keep single-phase. Inverters, EVs, and heat pumps are perfectly happy on single-phase up to surprisingly high power levels. The €1,500 saved is better invested in actual equipment than in capacity you may never use.
You know your phase. Now what could your roof actually produce?
Knowing your phase is one input — but it doesn’t tell you whether solar makes sense for your home. The real question is what your specific roof, with its specific orientation, its specific shading, and your specific consumption could realistically produce over the next twenty-five years.
The Enera calculator answers that. Drop a pin on your house, place panels on your roof, and you’ll see in thirty seconds: how many panels fit, how much energy they produce monthly and annually, and what percentage of your consumption they would offset. No signup, no email, no obligation — just the numbers for your roof.
If you uploaded your bill above, your phase and consumption are already filled in. The only step left is showing us where your house is.
Try the calculator on my roof →
Frequently asked questions
Does my electricity bill state phase type clearly?
Sometimes yes, sometimes no. Iberdrola and Endesa often write “Monofásico” or “Trifásico” plainly in the “Datos del suministro” section. Holaluz, Repsol, Som Energia, and many smaller retailers don’t always show it directly. If your bill doesn’t say it explicitly, look at the contracted power: below 10 kW is almost always single-phase.
Can I have very high contracted power and still be single-phase?
In Spain, yes — single-phase is permitted up to 14.49 kW under current regulations. Above that the installation must be three-phase. Most other EU countries cap single-phase at similar levels (10–15 kW). If your home draws more than this, it’s three-phase by definition.
Does single-phase vs three-phase change the cost of installing solar?
Slightly. Single-phase inverters are typically €100–€300 cheaper than equivalent three-phase models for systems up to 6 kW peak. Above 6–7 kW peak, three-phase is required (or at least strongly recommended for grid-export approvals). The savings on the inverter are small compared to total system cost — phase type is not a major price driver.
Do I need three-phase for an EV charger?
Depends on the speed you want. Single-phase home chargers cap at 7.4 kW (about 36 km of range per hour) — plenty for overnight charging of any EV. If you want 11 kW (60 km/hr) or 22 kW (120 km/hr), both require three-phase. For most home users, single-phase 7.4 kW is enough.
Can I switch from single-phase to three-phase myself?
No. It’s a substantial technical modification requiring an authorised electrician, a new CIE, and formal paperwork with your distribution company. DIY work here is illegal, voids your home insurance, and creates real safety risks (improper grounding, neutral imbalance) that can fry appliances or start fires.
Is three-phase more expensive in my monthly bill?
Not directly. The per-kWh tariff is the same. However the fixed monthly charge for contracted power capacity (término fijo) is per kW per day — so if you contract more capacity (which often happens when upgrading), your fixed costs increase. The energy consumed for the same workload is identical.
My new-build apartment — is it single-phase or three-phase by default?
Depends on contracted power and building type. Apartment blocks built since 2010 in Spain typically have a three-phase feed entering the building, but individual flats are usually wired single-phase from a centralised distribution panel. Single-family homes built since 2010 with electric heating or central AC may be three-phase by default. Check the CIE in your closing documents.
My neighbour has three-phase and I don’t — same building. Why?
Either historical (some flats were upgraded for specific tenant needs, others weren’t) or because they contracted higher power. In a multi-unit building, each flat has its own meter and its own contract; phase type is per-flat, not per-building. Building infrastructure usually supports three-phase, but the per-flat connection is provisioned based on each contract.