Ensuring that the foundation is properly built of the right materials is an integral part of any construction project. Transformer pads are no different. Perhaps even greater consideration is needed because they are buried in the ground, exposing them to many different environmental conditions.
Concrete and fibreglass are the most common materials used to make transformer pedestals. For many decades, concrete has been the leading choice of the Electrical Utilities sector. However, more and more utility companies are making the change to fiberglass. Why is there a shift in industry? Here are 4 reasons for this change.
- Strength to Weight Ratio
For concrete to be able to support the weight of a transformer, the walls of the transformer vault need to be thick and reinforced with rebar. This results in a T-Pad that weighs 2500 – 3000 pounds and can only be moved with the use of heavy equipment.
Fiberglass Reinforced Plastic (FRP) on the other hand is extremely strong for its weight. This strength comes from the combination of layers of chopped fibreglass mat that can be laid in precise directions to ensure maximum strength and the resins used to connect the layers of fiberglass. The final product is a transformer pad that weighs approximately 150 – 200 pounds that can still support transformers that weigh 5000 kg or more.
The high strength to weight ratio of fiberglass transformer pads benefit electrical utility companies in many ways. It means that the installation is easier as the T-Pad can be moved into place by hand if desired. If heavy equipment is used to maneuver the transformer tub into place, it is still safer to be moving something that is a couple hundred pounds versus something that is a few thousand pounds, especially when working in a confined area. The lighter weight FRP transformer base is also ideal for transporting into remote areas such as islands or northern locations that can only be accessed by ice roads.
An added benefit is that the fiberglass transformer vault has much thinner walls than its concrete counterpart creating a larger cavity to allow you to coil excess cable inside for future use.
While a transformer pedestal is almost entirely underground, it is still very susceptible to the effects of the environment around it. As we encounter in our every day lives, concrete is affected by freezing and thawing cycles, weathering, corrosion as well as wear and tear from vehicles and equipment. A traditional concrete transformer pad is not a base that will last generations without showing its age. At some point, it will have sustained enough damage that it will need to be replaced. This means additional labour and supply costs to replace it.
Fiberglass, on the other hand, lasts for generations. When sealed with a marine grade gel coat, it is virtually immune to environmental factors like sun, wind, snow & ice as well as corrosive substances like salt water and chemicals. This finish protects the fiberglass and resins from scratches, UV and moisture damage while adding a smooth, shiny finish. Because FRP is not a typical plastic, it does not become brittle in cold nor is it weakened by heat. An additional benefit of using FRP for your T-Pad is that should it be damaged at some point, it can be repaired on site. Other than needed spot repairs, fiberglass is maintenance free.
3. Shifting & Settling
Transformer Pads can be required to support weights ranging from about 800 pounds for a single-phase transformer to upwards of 25,000 pounds for a large 3 phase transformer. This downward pressure can have a significant effect on a cement transformer base settling and shifting over time.
When you choose an FRP transformer pad, they have been designed with an integrated flange. This flange helps to keep it from shifting because it provides a stable base to rest upon the soil and when it is buried, the downward pressure of the soil on top stops it from being able to shift up, ensuring that the transformer has a flat, stable surface to rest upon.
4. Freight & Storage
As mentioned earlier, a cement transformer vault typically weighs around 3000 pounds, which makes them not only bulky but heavy to ship. Because of their design, concrete transformer vaults cannot easily be stacked to allow for ease of keeping inventory on hand.
The design of an FRP transformer pad with a large cavity and smooth finish naturally lend them selves to stacking. This means that you not only save on freight due to their significantly lower weight, but you can also maximize the space on the transport truck and have more transformer bases delivered per delivery. This same stackability also allows for efficient storing of inventory.
Transformers are an important part of the electrical utility infrastructure and the foundation you choose for your transformer can have significant impacts on your business from the initial purchase and beyond. Ensuring you are investing in the right components, made of the right materials is an important step in the planning and purchasing process.
To find out more about how transformer pads designed by Structural Composite Technologies can help your utility organization, contact us today.