In Swedish
In English
In Danish

Construction description

Steel construction

We use steel as the construction material in our transformer stations - a natural choice thanks to the material's good characteristics. Steel is strong, workable and cost effective and can be used in many different contexts. The Swedish Environmental Protection Agency classes steel as the most eco-friendly construction material:

  • Steel is 100 per cent recyclable.
  • Steel is produced wholly or partly of recycled material.
  • Steel is part of a perpetual cycle. It can be recycled without any direct loss of properties.


Transformer station materials and their surface treatment are of critical importance for a station's lifetime. The sheet steel we use in our manufacturing process is aluzinc. The combination of aluminium and zinc delivers extremely good protection against corrosion, and when scratches occur zinc complements the aluminium by providing cathodic protection.

Aluzinc functions excellently in harsh environments where other types of surface treatments are not viable. For example, Aluzinc provides up to six times better corrosion protection than hot-dip zinc coated steel sheet. Aluzinc is a good environmental choice, not only for its long life but also from a recycling standpoint.

The above-ground part of the station is manufactured in Aluzinc, AZ150, while the station base is manufactured in AZ185, which offers heavier protection.

This is so the base is able to withstand the greater stress it is exposed to when embedded in the ground.


All of the sheet surfaces in the base are finished with a paint with excellent adhering abilities specially developed for use on zinc-coated surfaces. The paint is alkali resistant, which makes it extremely suitable as a coating for surfaces exposed to moisture as it prevents electro-chemical reactions.

Exterior walls
After priming, the exterior walls are finished with waterbased paint. The paint is well suited for treated sheet surfaces and any surface damage is easy to touch-up. Colours available are according to the NCS scale.

The station is supplied as standard with smooth walls that have a texture imparted by the paint.

The choice of exterior design, colour finish and facing etc. is in principle unlimited. There are three optional types of facing panel to choose from.

The roof is primed and then coated with the same type of paint used on the station's exterior walls. Roof colours available are according to the NCS scale. All standard roofs have a slope of at least five degrees to facilitate water run-off.

We are able to provide many different roof designs such as pitched roofs with 20 or 30-degree slopes, hip roofs or round roofs.

Exterior locks for non walk-in stations
The transformer station's outer doors are secured by padlock. A cover protects the padlock from snow and ice. In order to minimize the number of padlocks on certain types of stations the transformer door is opened from the low voltage compartment.

Exterior doors for walk-in stations
The station's exterior door is a multifunctional industrial door that can be fitted with locks of different manufacture. It can also be fitted with a panic bar and emergency exit signs.


Interior, roofs and ceilings in non walk-in stations

The ceiling and the inside of the station roof are treated with a well-proven water-based coating compound with excellent absorption and evaporative qualities that prevent the formation of condensation droplets.

The compound has good adhering properties on most surfaces and works well as heat insulation on aluminium or steel sheet roofs. The compound is flame and fire-resistant according to NT Fire 004 Class 1. In addition, the compound gives off no emissions to the environment; it also acts as a vibration and acoustic damper.

We use the compound in our stations chiefly because of its excellent ability to prevent the formation of condensation droplets on electrical equipment in the station. The indoor climate is improved considerably thanks to its range of application.

Floors in walk-in stations

The floor is made from board with a surface laminate that renders it durable, moisture resistant and easy to keep clean. The board is specially designed for electrical rooms. It has anti-static and flameproof protection, and because it's recyclable it's an eco-friendly choice.

The floor panels rest on steel joists welded together to form a framework. This framework creates a cable cellar that allows cable entry under the floor. A lifting tool is provided with each station, to facilitate the lifting of floor panels to access the cables beneath.

Internal walls in walk-in stations

After priming, interior walls are finished in a light colour with a paint developed for use on steel structures.

Insulation in walk-in stations

The station walls and roof are insulated with glass wool, which is water repellent and reduces the risk of corrosion. The cable cellar is uninsulated.

Ceilings in walk-in stations

After priming, the ceiling is finished with the same paint used for the interior walls.

Ventilation in walk-in stations

Switchgear room
The switchgear room is ventilated by the convective ventilation principle. As the station equipment gives off heat the latter rises in the station and is led out through ventilation ducts located high up. This creates a draught as ventilation ducts placed low down draw cold outside air in. The greater the temperature difference between the outside air and the air in the station, the greater the air flow. Air must be able to flow freely around ventilation ducts for the convective-ventilation principle to work.

Cable cellar
The formation of condensation on the underside of the floor panels is prevented by cable cellar ventilation through grilles installed in the station foundation.

Roof space ventilation
The space between the station roof and ceiling is ventilated via a narrow opening in the roof frame. This ventilation keeps the insulation dry and prevents the formation of condensation inside the roof.

Transformer compartment
Oil spill collection
There is always a risk of leakage in the event of an oilimmersed transformer breakdown. Therefore, beneath the transformer, there is a collection space that can accommodate the entire volume of transformer oil. Oil is collected in this space to avoid contaminating the environment.

The oil spill sump also acts as the station floor. If the transformer is not factory installed, supporting beams are included in the delivery to act as mountings. However, the floor is not built to withstand the weight of the transformer, but must rest directly on the ground beneath the station. Thus it's the ground that supports the weight of the transformer.

The transformer space is ventilated by the convective ventilation principle. Large ventilation grilles located low down draw in air from the outside. The air is heated by the transformer and exits the station through smaller grilles or the roof frames.

In certain circumstances forced air cooling may be necessary. In this case a thermostatically controlled fan can be installed to improve ventilation.


You can download manuals and our product catalogue in PDF format:


We always seek for the the most tasteful and practical solution possible in each individual case. Look at some examples of exterior design.
Gallery »