TRT®-MODULO Modular retention tank


Galvanised steel tank for electrical transformers exceeding transport gauges

The TRT®-MODULO range comprises several standardised one-piece modular enclosures with welded walls, hot-dip galvanised and fitted with width-adjustable beams. SANERGRID®‘s TRT-MODULO meets all the regulatory, technical, and environmental requirements for dielectric oil transformers from 160 kVA to 2000 MVA.




The TRT MODULO range allows 2, 3, 4, 5 or “N” retention tank modules to be connected using the SNG-Flow™ system. This solution is used for large transformers where the width of the bund exceeds the European transport gauge of 2,500 mm. This makes it possible to equip large electrical installations of up to 60T.


Description of the TRT-MODULO standard range:

  • S235 steel tank, thickness 3 or 4 mm; hot-dip galvanising certificate to ISO EN1461-2022.
  • Double watertight welding on all parts of the retention tank area to guarantee complete watertightness, with individual quality inspection before leaving the factory.
  • At the bottom of each TRT®-MODULO trough, a set of 2 support beams is installed in the width These adjustable beams make it easy to place the electrical transformer in the enclosure and keep it above the ground level of any residual water that may be present at the bottom of the enclosure when used outdoors. You can adjust the position of the TRT® beams on site to suit the centre-to-centre distance of your transformers.
  • The maximum weight of the transformer on the TRT®-MODULO enclosure is calculated according to the NFC 51.51 standard.
  • At the foot of the bund, two watertight wall penetrations are provided by 316L steel/stainless steel inserts to accommodate 1.5-inch diameter valves: the 1st valve to allow the bund to be emptied, and the 2nd to fit an SPI® rainwaters filtration kit. In the standard version, the bund is supplied with the two wall passages closed watertight with stainless steel plugs.
  • A safety siphon is always fitted to TRT-MODULO drip trays. Fitted to the bottom of the drip tray, it allows overflowing water to be drained away without draining oil in the event of heavy rain or blockage of the filtration system. Threaded outlet supplied without plug: don’t forget to remove the plug if using outdoors.
  • Each TRT has 8 earthing points with lugs at each corner of the tray (lugs not supplied).


Its basic design, high degree of solidity, robustness and versatility of use have made the TRT® -MODULO range a benchmark in the transformer retention tank market, whether for indoor or outdoor use, for short or long-term transformer storage, for use with live transformers, for new substations or substation refurbishment.


TRT® MODULO containers guarantee a service life in indoor and outdoor conditions similar to that of the electrical transformer or other machine they are fitted to and offer a high degree of customisation (see Accessories and Options tab).

Accessories and options

The TRT®-MODULO range consists of a series of monobloc retention tanks with the required retention volume and the length and width of the transformers they equip, depending on whether you use the tank indoors or outdoors. Please contact us with your transformer dimensions.


Depending on the configuration of your project, the TRT® range is available in several versions:

  • Width-adjustable beams for adapting the centre-to-centre distance to suit the transformer: TRT-W range
  • Fixed beams where the transformer centre distance is known: TRT-P-F-W range (widthways) and TRT-P-F-L range (lengthways)
  • Addition of a grating for walking on the transformer containment and access to the transformer control unit, DGPT2 or RIS2 type protection relays or auxiliary units: TRT-AUX range
  • When you have rising vertical cable ducts on the HV and LV side: TRT-H range
  • When you have rising vertical cable ducts on the HV or LV side: TRT-U range
  • For skid-mounted photovoltaic applications, to integrate the retention tank between the skid and the transformer: TRT-SKID range
  • Non-bearing bund when embedded in a retention pit, under an HV substation or photovoltaic skid: TRT-NP range
  • Extinguishing retention tanks: TRT-LHD range (monobloc) and TRT-LHD-MODULO range (modular with N connected modules)


This range also includes several accessories and options to suit your needs:

  • PETRO PIT kit, anti-hydrocarbons filter for rainwater drainage when the tank is used outdoors to allow continuous drainage of rainwater.
  • SANERVIB anti-vibration pads for installation at the bottom of the tank to reduce transformer noise and vibration.
  • Galvanic anti-corrosion treatment C5H GALVAGRID®.
  • Earthing of gratings or MALT.
  • Wheel locking calipers SANERBLOCK™.
  • Lifting hooks.

Technical data

Additional information



Conditions of use

indoor, outside



Fire resistance


Use and maintenance

Before installing the tank:

  • Make sure that the surface on which it is to be placed is smooth, flat, clean and, above all, large enough to take the weight of the transformer and the TRT® -MODULO tank.
  • Check that the positioning of the load pick-ups from the floor to the tray is appropriate, aligned and correctly dimensioned.
  • If the bins are stored outside, they must be emptied regularly, and not handled with water inside.


Installing the tank:

The unit must be unloaded using suitable handling equipment. Once installed in its final position, fix the support beams, adjusting the centre-to-centre distance so that the transformer is centred on the supports of the TRT® -MODULO trough.

Installation by crane:

Place the transformer on the trough beams, taking care not to obstruct the rainwater drainage holes. Avoid vertical acceleration or transverse shearing.



Regular visual inspection of the equipment should cover the following points:

  • Tightness at wall penetrations, accessories and/or plugs correctly screwed in.
  • Integrity of the tank walls, no deformation or damage (knocks, impacts, rust, etc.).
  • State of ageing of the hot dip galvanising protective layer and potential touch-ups.
  • Check that rainwater is flowing properly through the filters: if they are clogged, clean the pre-filters, or change the filters if they are saturated or have exceeded their recommended service life.
  • The frequency of these checks depends on the constraints of each site, depending on its degree of corrosion, dirtiness, presence of organic matter, etc.


Refer to the user manual for further details.

Failure to comply with good practice in use and failure to deal with anomalies and defects in the field are the responsibility of the owner of the equipment.

Additional information

Our transformers are in line with EU Regulation No 548/2014 also known as ECODESIGN on the implementation of Directive 2009/125/EC, which lays down eco-design requirements for the placing on the market or putting into service of transformers with a power rating of at least 1 kVA used in 50 Hz electricity transmission and distribution networks or for industrial applications. Called ECODESIGN Tiers 1 (2015) and ECODESIGN Tiers 2 (2021).


Our standard range of SANERGRID TRT retention tanks complies with French, European and international standards and recommendations concerning the retention of dielectric fluids, fire risk management, the management of contaminants and rainwaters in high-voltage substations and the protection of people and property.

  • French standards NF C13-100 and NF C13-200 prevent electrical risks, over currents, earthing problems, fire risks, short circuits and lightning, soil pollution and environmental pollution.
  • Standard NF EN 61936-1, relating to the design and installation of electrical installations, which requires watertight retention representing 100% of the volume of oil used, and provides the necessary indications for pre-dimensioning retention volumes and surfaces, fire safety distances and systems, and rainwater management associated with the outdoor storage of hydrocarbons.
  • CIGRE 23-07 and IEEE 980 recommendations on the use of fire suffocating covers for transformer pits and tanks, as well as guidance on the pre-sizing of indoor and outdoor retention pits and tanks.
  • Our retention tanks are designed and manufactured in accordance with the European norms and standards of EUROCODE 3 (Calculation of steel structures).
  • Our manufacturing plants are certified ISO 9001 for their quality management process and IS0 14001 for their environmental management process and are all based in Europe to encourage short supply chains and limit carbon emissions.
  • Our French and European sites enable us to guarantee that all our steel comes from European production, which is made up of over 50% recycled steel to limit the over-exploitation of resources and limit the carbon emissions linked to our manufacturing activities SANERGRID.
  • Rainwater drainage and oil pollution for outdoor use:
    Thanks to the SPI anti hydrocarbons filter system, the tank is empty most of the time and ready to receive hydrocarbons. In compliance with French water law (decree 77-254), the water discharged from the tanks is not contaminated with more than 5 ppm of hydrocarbons, in accordance with standard EN 858-1 (“light liquid separation installations”).
    SPI® filters are regularly tested by independent laboratories: SANERGRID Bureau Veritas report certified COFRAC I.D.: 003606/2776443/1/1/1 in 2015 (France), SPI Phoenix laboratory reports I.D.: AR67044 in 2002, 2004, 2005, 2009, 2018, 2022 (USA), TÜV report Nr 2432974 in 2016 (Germany), NUA report -Z-11895-1/1-2016. (Non-exhaustive list)


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