Electrical distribution boards, enclosures and accessories
Surface-mount · Flush-mount · Industrial · Construction · IP40–IP65 · 1-phase and 3-phase
The distribution board is the heart of every installation: this is where circuit breakers, RCDs, the meter and control elements connect. A wrongly chosen board – too small, wrong IP class or without reserve – causes overloaded junction boxes, failures and a serious fire risk. The right choice from the start saves money, stress and time.
Single-phase or three-phase – the first and most important question
Before choosing a model, size or mounting type – determine the supply phase:
|
Phase |
Where typically |
How to identify |
Board type |
|
1-phase |
Flats, small houses, garages |
2 wires at entry (phase + neutral) or meter type 1P |
Single-phase metering board |
|
3-phase |
Private houses, farms, industry |
4 wires at entry (3 phases + neutral) or meter type 3P |
Three-phase distribution board |
⚠ Important: Installing a single-phase board in a three-phase system is a common mistake. Result: breakers trip for no apparent reason, cables overheat. If in doubt – check the meter technical data sheet or contact your network operator.
Selection guide by situation
|
Situation |
Recommended type |
Phase |
IP class |
Modules |
See also |
|
Flat, renovation |
Surface-mount metering board |
1P |
IP40 |
18–24 |
Surface-mount boards |
|
Private house, new build |
Flush-mount three-phase board |
3P |
IP40 |
36–48 |
Flush-mount boards |
|
Apartment block unit |
Metering board for apartment blocks |
1P / 3P |
IP40–IP44 |
12–18 |
Apartment block boards |
|
Garage, storage |
Surface-mount enclosure (plastic) |
1P / 3P |
IP54–IP65 |
8–12 |
Specialist enclosures |
|
Construction site |
Portable construction board |
3P |
IP44–IP55 |
with sockets |
Construction boards |
|
Industry, commercial |
Switchgear cabinet (metal) |
3P |
IP54–IP65 |
per design |
Switchgear cabinets |
|
Outdoor installation |
Surface-mount IK10 with lock |
1P / 3P |
IP65 |
as required |
Specialist enclosures |
Surface-mount or flush-mount – two mounting principles
|
Type |
Mounting |
Advantages |
Disadvantages |
When to choose |
|
Surface-mount |
On wall surface |
Fast installation, no wall chasing needed |
Protrudes from wall |
Renovation, basement, garage, industrial premises |
|
Flush-mount |
Recessed into wall |
Aesthetic, does not obstruct movement |
Requires wall recess |
New build, living rooms |
IP class – not a formality, but a safety requirement
|
IP class |
Protection level |
Suitable locations |
Not suitable |
|
IP30–IP40 |
Protection against large solid particles |
Dry locations: living room, corridor, office |
Bathrooms, basements, outdoor |
|
IP44 |
Protection against water splash from any direction |
Bathroom zone 2, basements, garages |
Direct rain |
|
IP54–IP55 |
Protection against dust and water jets |
Garages, warehouses, construction sites |
Long-term submersion |
|
IP65–IP66 |
Fully dust-tight, protected against water jets |
Outdoor installation, car washes, agricultural sites |
— |
⚠ Safety requirement: In a bathroom (zone 1–2) IP class must not be lower than IP44. A board with IP30 in a damp location is a fire and electric shock risk. An outdoor board without IP65 – water enters the enclosure, short circuit, failure.
How to calculate the number of modules correctly
A module is a standard 17.5 mm width on a DIN rail. Each component occupies a certain number of modules:
|
Component |
Modules |
Note |
|
Circuit breaker (1P) |
1 |
One per circuit |
|
Double circuit breaker (2P) |
2 |
Cooker, boiler, A/C |
|
RCD / residual current device (2P) |
2–4 |
Bathroom, kitchen, outdoor circuits |
|
RCBO (1P+N) |
2 |
RCD + breaker in one |
|
Electricity meter |
4–9 |
Depends on model |
|
Relay, timer, controller |
1–2 |
Smart automation |
|
Voltage relay (2P) |
2 |
Overheat and surge protection |
After counting all components, add 30% reserve – not 20. Homes expand: electric vehicles, solar panels, heat pumps. A board full from day one becomes a problem in 5 years.
How to complete a board – what else is needed
Often a board is sold without the full set. Check that you have:
-
DIN rail — 35 mm standard. Some boards include it, others do not. Check the product description.
-
N and PE busbars — neutral and earth bars. Required for every board.
-
Terminal blocks — for cable connections. Select by cable cross-section (mm²).
-
Cable gland fittings — sealing where cables enter the board. Mandatory for IP44+ boards.
-
Lock or latch — if the board is in a public place or accessible to children.
-
Transparent covers — protect against accidental contact with live components.
What to check before buying
|
What to check |
Why it matters |
|
Single-phase or three-phase supply |
This determines the board type and the entire installation layout |
|
Module count with reserve |
A board too small – within 5 years it will need replacing or an additional board |
|
IP class for the location |
Wrong IP class in a damp location = fire and electric shock risk |
|
Mounting type (surface/flush) |
Flush mount requires minimum installation depth in the wall |
|
Contents (DIN rail, N-busbar) |
Some boards do not include these items – they must be purchased separately |
|
Cable entry position and size |
Thick cables must fit through the board opening – check dimensions |
|
Lock or latch |
In public spaces or where children are present – a requirement, not an option |
Most common mistakes – and their consequences
|
Mistake |
Consequence |
|
Board without module reserve |
After a few years – full replacement or second board installation |
|
IP30 board in bathroom or basement |
Moisture enters enclosure, corrosion, short circuit, fire |
|
Single-phase board in three-phase system |
Breakers trip, cables overheat, system does not work properly |
|
No N-busbar or PE-busbar |
Neutral and earth wires connected to breakers – failure and danger |
|
Cable entry openings not sealed in IP44+ boards |
IP class effectively drops to IP20 – protection fails |
|
Flush-mount board in wall too thin |
Cannot be properly installed, board or wall must be replaced |
Frequently asked questions
Can I install a distribution board myself?
A board can be installed by a person with electrician qualifications. Connection to the supply (meter cabinet, cables) must be performed by a licensed electrician – this is a legal requirement. Incorrect connection is life-threatening.
How many modules are enough for a private house board?
An average private house with heating, cooker, boiler, garage and lighting requires 36–48 modules. If you plan an electric vehicle, solar panels or heat pump – get a 54–72 module board. Better to have too much space than too little.
What is the difference between RCD and RCBO?
An RCD (residual current device) protects several circuits at once – economical, but when it trips the whole group loses power. An RCBO combines RCD and circuit breaker in one housing: it protects a single circuit and a fault does not switch off others. RCBO is recommended for bathrooms, kitchens and critical appliances.
Can I buy a board without a DIN rail?
Yes – many industrial and specialist boards do not include a rail. Always check the contents in the product table. DIN rails and N/PE busbars are available in the accessories section.
How do I select terminal blocks?
The terminal current rating and diameter must match the cable cross-section. For a standard 2.5 mm² cable – terminal up to 25 A; 4 mm² – up to 32 A; 6 mm² – up to 40 A. Solid core cables can be connected directly to breakers; flexible (stranded) cables – only with ferrules.
⚡ Doubt = ask us
Not sure about phases, module count, IP class or board contents? Write to us – tell us the object type and supply – we will reply with specific advice and help you avoid costly mistakes.
Tel.: +370 620 72733 | Email: info@elsprendimai.eu
