Transformer capacities: from 5kVA to 100MVA
- Grupo Edmar
- Sep 3
- 4 min read
September 03, 2025 - Transformer capacities.
Transformer capacities: from 5kVA to 100MVA.
In the world of electrical energy, transformers are essential components for ensuring that electricity reaches where it's needed safely and efficiently. These devices are manufactured in a wide variety of capacities , from small 5 kVA models to giants reaching 100 MVA , capable of supplying entire cities or large industries.
Knowing these capabilities not only helps you understand the scale of each transformer, but also helps you make better decisions when choosing the right equipment for each project.
What does the capacity of a transformer mean?
When we talk about the capacity of a transformer, we are referring to the amount of apparent energy it can handle without overheating or compromising its operation .
It is measured in kVA (kilovolt-amperes) for smaller equipment.
It is measured in MVA (megavolt-amperes) for high-capacity equipment.
In simple terms, capacity works like the “engine size” of a car: the larger it is, the more power it can deliver and the more applications it can cover.
It is important to emphasize that not choosing the right capacity can lead to serious problems:
If it is too small, the transformer will be overloaded and its lifespan will be reduced.
If it is too large, the cost will be much higher than necessary and investment will be wasted.
Small Transformers: from 5kVA.
Transformers with capacities between 5 kVA and 75 kVA are typically used in installations with moderate power consumption. They are compact and easy to install, making them a versatile option for multiple sectors.
Typical applications:
Residential : condominiums, small buildings or houses with high energy demand.
Commercial : offices, self-service stores, restaurants.
Light industrial : mechanical workshops, carpentry shops, small factories.
Example: A 25 kVA transformer can comfortably power the lighting, air conditioning, and equipment in a medium-sized office.
Additionally, small transformers are typically affordable, making them a practical investment for growing businesses.
Medium capacities: from 100kVA to 5MVA.
Transformers in this range are considered medium-duty and are designed for installations requiring higher continuous power. This is where we move into projects with more serious energy demands.
They are used in:
Hospitals , where electrical stability is crucial for the operation of medical equipment.
Shopping centers , which require power for retail stores, lighting, escalators, and air conditioning systems.
Medium-sized manufacturing plants , which require a constant supply of machinery.
Corporate buildings with multiple floors and centralized systems.
Example: A 1 MVA transformer can easily power an entire hospital, ensuring that all equipment operates even during peak demand times.
These devices are a compromise: robust, reliable, and capable of supporting high loads without having to match the cost or size of high-capacity transformers.
Large capacities: from 10MVA to 100MVA.
In this range, we find the giants of the electrical sector. Transformers from 10 MVA to 100 MVA are intended for large-scale projects , where huge amounts of energy need to be handled to supply entire regions or large industrial parks.
Some applications:
Electrical substations for regional distribution.
Power generation plants (hydroelectric, thermoelectric, wind).
Industrial megaprojects , such as automotive, mining or steel plants.
Industrial parks with multiple factories operating simultaneously.
Example: A 50 MVA transformer can power an industrial park that houses dozens of manufacturing companies.
This type of equipment requires more complex installations, advanced protection systems, and specialized personnel for its operation and maintenance.
Factors to consider when choosing capacity
The choice of a transformer cannot be based solely on price. There are several key factors that help define the correct capacity:
Current electrical demand : how much energy the project needs in normal operation.
Future demand : It is recommended to calculate a growth margin to prevent the transformer from becoming obsolete.
Type of load : whether it is electronic equipment, electric motors, air conditioning systems, etc.
Current regulations : compliance with local and international regulations is mandatory.
Environmental conditions : height, ambient temperature and available space influence the choice.
For example, a business planning to grow in the coming years should consider a transformer with a slightly larger capacity, in anticipation of expansion.
Availability and delivery times.
One of the main challenges in transformer procurement is immediate availability . While a small transformer may be in stock, large-capacity transformers are typically made to order, with lead times ranging from 12 to 36 weeks .
This is where having a supplier like Grupo Edmar is key, as we manage available inventory in certain capacities and offer rapid solutions for urgent projects.
For example, a company that needs to start operations in less than two months can't wait half a year for a transformer. Having the option of rapid delivery becomes a huge competitive advantage.
Standards and Certifications.
A quality transformer must not only meet its rated capacity but also be certified under standards that guarantee its safety and performance. Among the most important:
NOM (Mexican Official Standard) : required in Mexico for most electrical equipment.
ANSI (American National Standards Institute) : a widely used standard in North America.
IEC (International Electrotechnical Commission) : international recognition for global projects.
Compliance with these standards ensures that the transformer is reliable, efficient, and accepted in official audits or inspections. It also provides peace of mind to the buyer knowing their investment is supported.
Edmar Group: a reliable choice in any capacity.
At Grupo Edmar, we have experience supplying transformers in a wide range of capacities, from 5 kVA for small projects to 100 MVA for large substations.
Our added value is not only in sales, but also in:
Personalized advice to choose the right capacity.
Immediate availability in certain capacities.
Compliance with national and international standards .
Thus, our clients can rest assured that they will find in Grupo Edmar a reliable partner for any electrical project, regardless of its size.
