Cleaning & Painting 


Preventative maintenance to reduce corrosive attack on transformers is best applied by specialists. Ensuring protective coatings are applied to the most vulnerable areas is vital on all transformers from the smallest distribution transformer to the largest supergrid transformer.

The cleaning and painting process includes steam cleaning and de-rusting, followed by painting with airless spray, or by the flood coating method. On large transformers the radiator banks have to be painted by the flood coating method in order to ensure the more inaccessible areas are properly coated.

Utilising Rosh Engineering's multi skilled workforce ensures that both cleaning, painting and mechanical works can be completed by the same team during our visit to the site. A regular cleaning and painting programme will ensure that no mechanical failure of a transformer or associated equipment during its life cycle, keeping the operating costs down in the long term.

A typical paint specification applied to transformers is one developed by the UK's former Central Electricity Generating Board (CEGB) as follows:


Formulation Standard
Colour Standard
Zinc Phosphate
BS 5493 Type FP3A
BS 5493 Type FU1B
Natural Pigment
Top Coat:
Grey Gloss
BS 5493 Type FF3A
BS 4800 18B25


The British Standard for this specification recommends re-painting every 5 years in a 'marine' environment such as in a coastal location or within a few miles of the sea, and 10 years elsewhere.  Other specifications can be applied according to customer requirements although we recommend choosing a system that will readily accept re-painting without major abrasion being required. Some painting systems offer a slightly longer life between re-application but require all surfaces to be shot blasted or heavily abraded. This is not always possible or practical when transformers are installed, nor easy with large cooler banks having surfaces that are inaccessible.

Rosh engineers are available to give a full assessment on the plant's condition and provide advice for regular maintenance schedules according to each site's individual environmental conditions.

Rosh will also include associated high voltage (HV) plant within the cleaning and painting plans, such as switchgear, structures, auxiliary transformers, Liquid Neutral Earthing Resistors, and if necessary the substation fencing.

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