What different types of groups do you have in a home?

What different types of groups do you have in a home?: 1-phase and 3-phase connections in homes

The main connection
A home can have a 1-phase or 3-phase main connection:
• 1-phase, e.g. 1x25A, 1x40A or 1x63A
• 3-phase, e.g. 3x25A, 3x35A or 3x40A

The terminal groups
From this main connection at the meter box, we enter the house with a number of types of terminal groups. A terminal group is an electrical chain that feeds appliances and outlets. A terminal group is electrically protected against short-circuits and overcurrents (the circuit breaker) and usually also against fault currents (with the earth leakage circuit breaker). We have the following terminal groups:
• 1-phase, usually 16A
• 3-phase, usually 16A
• Cooking group connection 2x230V mostly 16A

Main connection 1-phase 3-phase
1-phase 230V groups x x
3-phase 380V groups x
2x230V Cooking group x x

• 1-phase 230V group (P+N)
Possible with both a 1-phase and a 3-phase main connection.
Has a maximum load capacity of 16Ax230V= 3,680VA
The conduit in a 1-phase group contains:
• Phase : L (usually brown, but can also be black or grey)
• Neutral : N (blue))
• Earth : PE (yellow/green)
Usually protected by a 16A circuit breaker.
Some of these groups are protected by a common earth leakage circuit breaker. (max.4)
Used to supply wall sockets and lighting groups.
Used Wieland GST18 connector: GST18i3 black L, PE, N possibly GST18i3 coding grey/red and salmon pink are suitable

• 2x230V Cooking group (2P+2N)
Possible with both a 1-phase and a 3-phase main connection.
Has a maximum load capacity of 2x(16Ax230V)= 7,360VA
This is a solution found only in the Netherlands. Consists of two 1-phase groups with a common earth in 1 conduit or 5-conductor cable.
The cable in a 2x230V cooking group contains:
• Phase : L (usually brown)
• Neutral : N (blue))
• Phase : L' (usually black)
• Neutral : N' (blue, but in a 5-conductor cable the grey wire is often used)
• Earth : PE (yellow/green)
Protected with a so-called cooking group circuit breaker. 2 switched 1-phase circuit breakers that switch off simultaneously using a bridging clamp.
Used Wieland GST18 connector: GST18i5 green: 1: L1, brown; 2:L2, black; PE yellow/green; : 3/N N1 blue; 4: N2 grey

• 3-phase group (3P+N)
Only with a 3-phase main connection.
Has a maximum load capacity of 3x(16Ax230V)= 11,040VA
The conduit in a 3-phase group contains:
• Phase : L1 ( usually brown)
• Phase : L2 ( usually black)
• Phase : L3 (usually grey)
• Neutral : N (blue))
• Earth : PE (yellow/green)
The 3-phase group is usually used as a power connection to connect appliances that consume a lot of energy, such as heavy cookers, a jacuzzi or EV charging stations.
Protected by a 3-phase circuit breaker
Used Wieland GST18 connector: GST18i5 black: 1: brown, 2: black, 3: grey, N: blue, PE: yellow/green. Optionally, GST18i5 coding grey/red can also be used.

In a 3-phase group, when the phases are all under maximum load, normally no current runs through the neutral, hence the name. This is because the return currents do not pass through the neutral but through the phases themselves. With unequal loads, a maximum of the rated phase current (16A) can flow through the neutral, which is why, although there is much more power available in the group, the neutral core is as thick as the phases.
The current through the neutral must be prevented from becoming greater than the rated phase current due to either harmonic distortions (due to certain loads such as switched-mode power supplies) or strong capacitive or inductive loads on one of the phases that may cause a phase shift.

It is also possible to split the 3-phase group into 3 1-phase groups only after the meter box.
With conventional residential installations, this is not often done, but in pluggable installations in both residential and non-residential buildings, it is an interesting option to save time, space and material, and have less copper losses in the installation.
This is used, for example, in kitchens where a lot of power is needed. A 3-phase group with a 5-core cable is then routed to the kitchen which is split there into 3 single phases with 3-core cables. In a pluggable installation, this is done with a 3-phase splitter which is fed with a 5-core 3-phase GST18i5 2½mm² cable and from which 3 sections of 3-core GST18i3 2½mm² cables are tapped.
If the 1-phase lines are as thick as the 3-phase line, i.e. normally at least 2½mm², there is no need to install additional protection at the junction point.

Many cookers can be connected in different ways:
• With a cooking group (2P+2N)
• With a 3-phase group (3P+N)
• With 2 phases from a 3-phase group (2P+N). The 3rd phase can then be used to connect the separate oven, for example.
See also our FAQs on cooker connections for this.

The maximum current through the Neutral in a 16A protection system
• In a 16A 1-phase group (P+N), the current through L phase is equal to that through Neutral N, so maximum 16A
• In a 2x230V cooking group (2P+2N), the current through each L phase is equal to that through the corresponding Neutral N, so maximum of 16A
• In a 3-phase group (3P+N), the current through Neutral is ideally 0A, but in the extreme case it is a maximum of 16A.

The above refers to:
• P for phase is the same as the L of Live
• N for Neutral
• PE for Protective Earth or Earth

For an explanation of 3-phase systems see also https://en.wikipedia.org/wiki/Mathematics_of_three-phase_electric_power

Home ← Expertise ← FAQ's ← Pluggable electrical installations and cooking appliances ← What different types of groups do you have in a home?

Share on