Medium voltage

Compact stations have been developed for all insulated medium voltage switches manufactured in Europe. Applying open switches is also possible.



The Diabolo transformer substations are available with the following capacities:

  • 630 kVA
  • 1,250 kVA
  • 2,500 kVA


Low voltage

Virtually all imaginable specifications can be built due to the special modular construction system.



The stations can host low-loss or used transformers with capacities up to 2,500 kVA.


Solid casing

The station is cast monolithic, meaning the entire station is cast as a single piece. The exposed side is made of smooth, grey concrete. The concrete quality is at least B45.


Temperature control

Specially developed Alfen grids guarantee optimal ventilation. Choose from K10, K20 or K30 stations, that fully comply with IEC 61300 (K20 is the default option). Grids are detachable for inspections and maintenance.


Oil drip tray

All stations are equipped with an integrated monolithic cast oil drip tray for maximum security and environmental protection.


Water discharge

The clever roof construction design and level differences in the sidewalls, rain water follows a regulated, natural path toward the earth’s surface.


Detachable front panels

A lightweight, shared, detachable front panel is located under the door. The Diabolo transformer substations are available with waterproof concrete sealing (equipped with cable entry points).


Available in every possible color

The station can be delivered in every possible RAL color. By default, all stations have a smooth concrete surface with an anti-graffiti coating.



Whatever the soil composition is, Alfen has the right foundation available, for instance with steel or pile foundations. Of course these foundations can also be installed by Alfen.


Transport and placement

Alfen can carry out all transport placement tasks at any possible location. To ensure a safe and professional execution, all staff members involved are SCC certified.



Construction type Prefab concrete with detachable roof
Dimensions 310 x 250 x 210 cm (L x W x H) (height above surface level)
Clearance MV opening 210 x 130 cm (W x H)
Clearance LV opening 210 x 130 cm (W x H)
Clearance transformer opening 80 x 120 cm (W x H)
Lock Door handle with 17 mm euro profile cylinder
Cable entries MV side Access through detachable front cover panel
Cable entries LV side Access through detachable front cover panel
MV installation dimensions (max)   200 x 80 x 160 cm (W x D x H)
LV installation dimensions (max)   200 x 45 x 160 cm
Transformer installation dimensions (max)  205 x 120 x 220 cm (L x W x H)
Casing weight 8,750 kg
Design standard IEC 62271-202
Temperature class Class 20
Finishing concrete Exposed concrete light grey. Anti-graffiti coating.
Finishing cover panels Varnish color light grey (RAL 7044)
Lighting MV and LV area Lamp operated by door switch
Wall socket MV and LV area Wall socket with 16A grounding
Security lighting 16A circuit breaker
RCCB  25A 30mA
Power supply 230V-50hZ
Grounding equipment Equipment and metal parts connect to grounding bus bar
Grounding electrode MV and LV area Connection terminal 25-95mm2
Connection point grounding equipment MV and LV area Ball knob round 25mm
Drawings Dimension sketch MS4408A801. Foundation MS4408A109