When it comes to public transformer placement,  ground-mounted transformers and three-phase pad-mounted transformers are quite similar to pole-mounted transformers since these transformers are commonly seen on public, which is why learning the pad-mounted transformer diagram is a great way to understand how these transformers are safe in public

With the help of DAELIM, a company that has been manufacturing ground-mounted transformers for decades, you will be able to understand what this electric device is capable of, and if you should consider purchasing one for your project.

Choosing the right transformer manufacturer is also just as important as choosing the right type of transformer. High-quality transformers will go for as long as 40 years if manufactured professionally, and regularly maintained by the owner.

The Complete Guide to Ground Mounted Transformer

Single Phase and Three Phase Pad-mounted Transformer From Daelim
Single Phase and Three Phase Pad-mounted Transformer From Daelim

Pad-mounted Transformer

We can provide you single phase and three phase pad mounted transformer

Dry-type Transformer

Type:Cast resin; Rated Capacity: Up to 25MVA; Rated Voltage: Up to 36KV;

Pole Transformer

TypeCSP type Frequency: 50/60Hz; Rated Power: 5~167kva

Dry-type Transformer

Frequency: 50/60Hz Rated voltage:10kv, 20kv,30kv Rated Power: 400~2500kva


What are Mounted Transformers?

Since this article will be focusing on two types of mounted transformers, which is the ground-mounted transformer and pole-mounted transformer, it is best to learn first why they are called mounted transformers.

Basically, transformers are usually seen on the ground, whether it is near a building, inside a power plant, or some remote area. The point is that transformers are basically seen standing in their place or on the ground.


Whereas mounted transformers are specifically mounted on to something while they are operating. They are leveraged to operate efficiently, this is why their sole purpose and design has a mounting utility on it.

What Are Ground-mounted Transformers?

Ground-mounted transformers are basically transformers that are placed on a concrete pad that is mounted to the ground. These are distribution transformers with a kV rating that is significantly lesser than typical distribution transformers.

This is because their build or construction is much smaller than normal transformers that can fit in more components that is a major contributor to the increase in kVA rating (kilovolt-ampere). Moreover, the material of the plate or pad that it is settled in can be made out of solid wood or concrete since these are non-conductive materials.


When it comes to the Ground-mounted transformer’s enclosure, they basically look like a small or big cabinet since there are ground-mounted transformers that can be as small as a storage box and some can be as big as a locker.

Regardless of the size, they are normally seen in a locked metal cabinet and the purpose of this is to keep people, animals, debris, and other outside elements from tampering with it while it is operating.

Small or big, ground-mounted transformers will always have a pad underneath them.This makes them easy to identify and distinguish among other transformers.


ground-mounted transformers have a unique working principle that allows primary cables to be connected with help of elbow connectors. This will be operated when it is energized, and with a use of a hot stick. Moreover, this enables users to repair and do maintenance much easier.

Ground-mounted transformers are also known to have underground connections, specifically underground utility lines that lead to service drops, which is an overhead electrical line that is running from a utility pole towards a consumer’s house or establishment.

The main function of this is to do what distribution transformers usually do, which is to decrease or “step down” the primary voltage on the utility distribution lines that is direct to a lower voltage. Specifically a lower secondary voltage for supplying consumer needs.

This is why ground-mounted transformers are able to supply electricity to numerous buildings, which is why it is not surprising to see a single ground-mounted transformer supplying a single household or large building.

This is why a lot of consumers, businesses, and companies prefer ground-mounted transformers since they are of the right size, easy to operate, and have the ability to provide sufficient electricity, which is good for almost any kind of project.

Get the most complete Pad Mounted Transformer information now!


In terms of the area of where ground-mounted transformers should be placed, a lot of consumers tend to ask whether they can be placed indoors and underground, but you will get to know the answer to that in the frequently asked questions section.

Focusing on where you can commonly find ground-mounted transformers, as mentioned they can be seen almost anywhere in public. Some are even near pedestrian lanes, which does make you think if it is just safe to pass by or pass through.

Maintenance Procedures for Pad Mounted Transformers

Daelim's pad mounted transformer installed in Honduras
Daelim's pad mounted transformer installed in Honduras

Basically, it is not uncommon for ground-mounted transformers to be seen in residential areas. This is actually the reason why this type of transformer is also called “residential pad transformers” since it is normal for them to be seen in people’s front yards or front lawns.

The reason why they can be seen outdoors and near buildings is because unlike other types of transformers, ground-mounted transformers have their contact points that are live stored in a grounded metal box. The result of this makes the overall transformer safe to showcase or present in public areas, including houses that are close together in residential areas.

As you may have observed with other transformers, specifically ones that are not suitable for public locations, they are normally seen enclosed in a metal fence to protect pedestrians from coming in. 

When it comes to ground-mounted transformers this is simply not necessary. However, you do normally see them with a safety lock to avoid pedestrians from tampering with it..

What is a Single-phase Ground-mounted Transformer?

Single Phase Pad-Mounted Distribution Transformer near house
Single Phase Pad-Mounted Distribution Transformer near house

Single-phase ground-mounted transformers enable vertical feed to the primary and secondary bushings of the transformer. Single-phase ground-mounted transformers are the ones you normally see on industrial and residential applications. Because of this, there is a wide range of kVAs required and as well as a lot of cable involved.

Moreover, single-phase ground-mounted transformers accept single-phase alternating current (A.C) power. This involves the output for the single-phase A.C power that is usually between a higher or lower voltage level.

During this process, energy is also transferred from one circuit to another through the law of electromagnetic induction.


What is a Three-phase Pad-mounted Transformer?

When it comes to Three-phase pad-mounted transformers, the distinct difference between them compared to single-phase ground-mounted transformers is that they are used to change voltages with three phases.

Basically, three-phase pad-mounted transformers go through this process. This means that they are commonly used for power generation and as well as electrical distribution network applications.

2021 Ultimate Dry Type Cast Resin Transformer Guide

What is a Pad-mounted Transformer Diagram?

A pad-mounted transformer diagram refers to what the transformer itself does, and as well as how it works. As mentioned, ground-mounted transformers are operated with the help of underground electric power distribution lines at service drops, which is to step down the primary voltage to the lower secondary voltage to provide consumers electricity.

Those big green metal utility boxes in the streets of towns and residential areas are ground-mounted transformers that are operating to lower high voltage to standard consumer voltage.

Part worth noting of the pad-mounted transformer diagram is that these transformers are not in any way protected like the way overhead lines and substations are.

What Are Pole-mounted Transformers?

Basically, pole-mounted transformers are those barrel-shaped objects that you usually see at electricity poles or utility poles. Pole-mounted transformers are also part of the distribution transformer category but instead of being planted on the ground, these transformers are mounted on an electric service pole that is made out of concrete or wood.

In terms of their height in a utility pole, these are leveled with electric wires, which is the reason why you see a lot of wires connected to a single pole-mounted transformer.

The Complete Guide to Pole-Mounted Transformer

Pole-mounted Transformers
Pole-mounted Transformers

What is the Rating of Pole-mounted Transformers?

The usual rate of Pole-mounted transformers range from 16 kilovolt amperes to 100 kilovolt amperes. It may not seem much but in terms of how much electricity they can transform, they have the ability to shrink 11,000 Volts – 33, 000 Volts to 400 Volts. They may be small, but there is no question about their ability to do that.

Another use case for pole-mounted transformers is converting distribution voltages to the 120/240 rate of the power system. This is the common rate that is used by consumers such as houses and other small to medium sized establishments.

Seven Technical parameters of Pad-mounted Transformers

What Is Inside a Pole-mounted Transformer?

For starters. pole-mounted transformers are considered as static devices that have no moving parts in them, but this does not mean that they are completely inside. Like most transformers, pole-mounted transformers have a magnetic core that is generated from laminations of silicon sheet steel. This is also known as “transformer steel”. The arrangement of this setup is stacked with the primary and secondary wire windings wrapped around them.

parts of pole-mounted transformer
parts of pole-mounted transformer

What are the Wires Connected to a Pole-mounted Transformer?

Each building or establishment may or may not have a transformer drum in their vicinity and it is mounted to a utility pole. However, this is not always the case for pole-mounted transformers since they can be located underground if buildings are too close to each other, like suburban neighbourhoods. Each house will have a transformer box underneath them.

2021 Ultimate 3 Phase Transformer Chart Guide

What is the Main Difference between Single-phase and Three-phase?

For starters, single-phase, like single-phase ground-mounted transformers, need two wires. On the other hand three-phase, like three-phase pad-mounted transformers need three or four wires.

Single-phase ground-mounted transformers simultaneously change the supply voltage of an alternating current power by a system.

Furthermore, single-phase power is a two-wire A.C power circuit while three-phase is a three-wire A.C power circuit. In terms of the three-wire A.C power circuit, each phase is expected to be 120 electrical degrees apart

Are Ground-mounted Transformers Hazardous?

Basically, the design of ground-mounted transformers is what makes it a safe public transformer. This goes to show that ground-mounted transformers do not pose a threat to people who are standing near it or passing by.

But for the safety of the pedestrians, it is best to avoid contact with a ground-mounted transformer. Better yet, put a warning sign near since children might play around with it or worse, play on top of it.

The safe distance recommended is at least 3 letters from any ground-mounted transformer.

How to ground the pad-mounted substation?

Can Ground-mounted Transformers Be Placed Indoors?

When it comes to transformers that can be placed indoors, people who have knowledge about transformers would usually think of dry-type transformers as a best example for indoor placement.

However, for ground-mounted transformers, this usually depends on the transformer if its rating meets the safety standard of the establishment. Since ground-mounted transformers make use of transformer oil or mineral oil, this means that they are highly flammable.

Public buildings have fire codes with them, so depending on the rating and fire code of the building, ground-mounted transformers may or may not be placed indoors.

2021 Ultimate Different Types of Transformer Guide

What is the Difference Between Indoor and Outdoor Transformers?

Install Pad-mounted Transformer
Install Pad-mounted Transformer

Aside from the obvious and simple explanation that indoor transformers are specifically for indoors, while outdoor transformers are specifically for outdoors, there are standards to consider to declare if a transformer belongs to the indoor or outdoor transformer category.

For ground-mounted transformers, it is best to locate them outdoors. They are highly flammable so it’s best to keep them out of establishments. Nevertheless, it is not worth taking the time to worry about its condition outdoors since the design is very solid.

How to Choose a Power Transformer From China?

Final Thoughts about Ground-mounted Transformers

There is no doubt here that ground-mounted transformers are excellent transformers. But if your project requires higher voltage levels, then it is best to choose pure distribution transformers or power transformers.

But if your project only requires electricity that can provide one to multiple buildings, then ground-mounted transformers are definitely for you. They are small, easy to operate, and safe to place outdoors.

Should you have any questions or concerns, please do not hesitate to contact DAELIM’s team of professionals for professional help.

Custom Ground-Mounted Transformer

Each country has its own electrical industry regulations. They will have their own requirements for ground-mounted transformers according to their own conditions. If you find that the existing transformer cannot meet your requirements. Daelim is willing to use its 15 years of transformer design and production experience to produce and design a Ground-mounted transformer suitable for you.

Contact us and you will have Daelim’s efficient and stable Ground-mounted transformer.

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