What is the quickest way to find out what benefit I have?

Usually the main switch and panel indicator lights give the most direct picture. Alternatively, the DEDDIE bill and meter clearly confirm this.

If I have three lights on the panel but one is off, does that mean I went single phase?

No. The indicator light may be burnt out or a phase may be missing due to a fault. It is not in itself an indication of a change in type of provision.

How to Check if Your Home Has a Single or Three Phase Panel: A Quick Visual Check for Beginners

You are moving to a new apartment or have just bought a second-hand property. You want to apply for a new electricity contract or are thinking of buying a large electrical appliance. The first question the operator will ask you at the telephone service is: "What supply does the property have? Single phase or three phase?"

Often, the previous owner does not know, and you are not an electrician to open wires. The good news is that you don't have to be a techie or call a professional to find out. Your electrical installation is full of visual "signs".

As engineers, we made this simple, practical guide to identify your current type in less than 1 minute using 4 different methods.

Method 1: Look at the Master Switch on the Table (Quickest)

Open the door of the electrical panel inside the house. Look to the upper-upper left, where the Master Switch is (usually the largest component, often with a red or black lever). The difference in size "shouts" the type of supply:

If it is Single Phase

The master switch is tight. It usually takes up the space that would be taken up by 2 simple fuses side by side (in the language of electricians, it is "bipolar"). It has a single, relatively narrow lever to raise and lower.

If it is Three Phase

The master switch is bulky. It occupies the space that 4 simple fuses would take (it is "four-pole"). Its plastic lever is very wide, because it essentially joins four separate switches internally that all go up and down together.

Method 2: Count the "Lights" (The Indicator Lights)

This is probably the most beginner-friendly way, as long as the board is not completely ancient. Right next to the Master Switch, there are some indicator lights (usually red, orange or green).

If you have 1 bulb

The house is almost certainly Single Phase. It lights up to show you that "one" phase is bringing power from the street.

If you have 3 bulbs (in a row)

The house is three-phase. Each light corresponds to one of the three phases of the network (L1, L2, L3).

Caution (Engineer's Tip)

If you have 3 lights, but one is off, it doesn't mean it "became" single phase. It means either that the light bulb burned out, or that DEDDIE has a fault and "lost" one phase in your neighborhood!

Method 3: Look at the DEDDIE Clock (On the Sidewalk or Underground)

If the house is locked and you don't have access to the internal panel, you can find the answer by going down to the ground floor of the apartment building or checking the "box" (meter) on the sidewalk.

Find the clock that corresponds to your apartment and look at the labels and letters on the dial (whether it's the old analog with the rotating disc, or the new digital):

Illustration for Method 3: Look at the DEDDIE Clock (On the Sidewalk or Underground)

Single Phase Meter Signals

You will see it say "Monophase", or "1-Phase", or the 1Φ symbol. Also if you look at the operating voltage it will just say 220V or 230V.

Three Phase Meter Signals

You will see it say "Polyphase", "Three-phase", or the 3Φ symbol. The clearest sign is that the voltage will say 3x230/400V (or 3x220/380V in older ones). Also, the physical size of a three-phase meter is noticeably larger.

Method 4: The Power Bill (Without Getting Off the Couch)

If you have your hands on an old electricity bill for the property (any provider), the answer is printed there, as long as you know where to look.

Go to the section of the bill that lists the technical characteristics of the connection (usually where it says "Type of Provision" or "Agreed Power"):

If the "Agreed Power" says 8 kVA (the most common), 10 kVA or 12 kVA

The house is single-phase. (Also often listed as "Delivery 1" or "Delivery 2").

If "Agreed Power" says 25 kVA, 35 kVA, 55 kVA or above

The house is 100% Three Phase. (Also listed as "Delivery 3", "Delivery 4", etc.).

Summarizing

As you can see, there is no mystery surrounding furnishing your home. Whether you check the thickness of the master switch, count the light bulbs, or just look at the bill, the information is readily available. Now you're ready to talk to your carrier or order your new devices with confidence!

Next Step: We have seen how the three-phase current looks like in the table. But how is this powerful current transferred to specialized devices? Certainly not with the simple, classic wall outlet. Continue to the next article: Three Phase Outlets & Industrial Plugs (CEE): What they are, where they fit and how to connect safely, to learn about the world of "red plugs".

Single-Phase or Three-Phase Current? The ultimate guide to choosing what your home needs When to Upgrade to Three-Phase Supply: Heat Pumps, Wallboxes and "heavy" consumptions Power Extension (DEDDIE): The process, supporting documents and costs step by step (Guide 2026) Can a Single Phase Home Sustain an Electric Car? What is true in practice?

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