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Transformer Maintenance Checklist 101

Transformer Maintenance Checklist 101

Transformer Maintenance Checklist

Transformers, like any other electrical equipment, require regular maintenance as well. With proper care, a transformer can function smoothly, increasing your productive workflow and ensuring a longer equipment life. We understand that putting a regular transformer check on your schedule might be hectic, with many different parts and components requiring individual care and attention almost daily, some even hourly. Hence, we have come up with the most comprehensive checklist for the maintenance of electrical transformers. Read on to learn more about the essentials to keep your transformer healthy in this article.

What Is The Importance Of Transformers In An Electrical Power System?

Transformers can be generally defined as voltage-controlling devices allowing the distribution and transmission of current. It is widely used in electrical industries to handle high voltage electric current and distribute it in low voltages for consumption. This is necessary as the high voltage current, when distributed directly to your homes, may lead to short circuits and destroy your electrical appliances.

Electrical transformers work on the principle of electromagnetic induction and work by increasing or decreasing the supply voltage. Thus it helps in the seamless movement of electricity from generating power plants to homes and offices. As such, the importance of transformers in an electrical power system would include:

  • Converts high voltage AC to low voltages so that it’s safer to distribute 
  • Safe medium to distribute electricity over long distances.
  • Helps prevent damage from High Voltage AC in a circuit
  • Controls the power of AC, which helps in lowering your electricity bill

How Does An Electrical Transformer Work?

As we know, a transformer works on the principle of electromagnetic induction and alternates current from higher to lower voltages. Hence, a transformer doesn’t itself create energy but is a mere distributor of energy by changing the voltages to suit the needs of different circuits.

The electricity enters the transformer through the primary coil. With this, there forms a moving magnetic field around the coil. The secondary coil from which the current is distributed at a lower voltage is placed near the primary coil. Thus, with the moving electric field, the current is either increased or decreased based on turns taken by the current. Wrapping the two coils together ( the primary and secondary coil) with the primary one with a few more loops than the other one generates a current at a lower voltage in the second coil than it is present in the primary coil.

Checklist For Daily Maintenance Of Transformers

There are a few components of transformers that are required for daily maintenance. This type of regular checking on your transformers is also known as conditional maintenance. As such, your daily checklist for electrical transformer maintenance must include the following:

  • Check the transformer yard to ensure no object may disrupt the transformer’s working.
  • Ensure that the re-extinguishers are free from dust so that they may quickly work in the face of an emergency.
  • Make sure the transformer is clean and placed in a proper space.
  • Keep track of any abnormal noises in the transformer to avoid costly breakdowns.
  • Look out for loose connections in your transformer, mostly around earthing and surge arrestors.
  • Keep a note of the reading on the winding temperature of your transformer.
  • Check the incoming supply of current. Keep it is in the ON position.
  • Also, look at the re-buckets occasionally to check for enough sand.
  • Ensure you check the oil temperature, hourly level, and voltage points.

Components That Require Annual Maintenance Of Transformers

You must get the transformer checked in detail, on a yearly basis. Some of the parts you need to check may include oil pumps, air fans, control circuits, and other components that work together for the function of the cooling system. With the cooling system checked, you can get an overview of the physical condition of your transformer. 

The bushing must be cleaned with soft cotton cloths and checked for cracks. Though it is recommended to have a half-yearly check for the oil condition of your transformer, a yearly oil test is mandatory for your transformer. You must also get a mechanical inspection done as a transformer works under heavy current pressures, which makes it prone to damaged parts.

Apart from this, you must get the marshalling boxes cleaned and checked along with other functions like illumination, space heaters, terminal connections, relays, alarms, control switches, etc. Other important aspects to check for may include insulation resistance, battery power, and DGA (Dissolve Gas Analysis).

The Ultimate Monthly Checklist For Your Electrical Transformer Maintenance

Transformer Maintenance Checklist

The ultimate checklist for your monthly electrical transformer maintenance would include the following:

  • Examine the transformer tank, bushings, cooling system, and accessories for any signs of damage, such as oil leaks, corrosion, rust, or physical damage.
  • Inspect the transformer for any debris, plants, or other objects that might interfere with its ventilation.
  • Utilize the gauge glass or level indicator to determine the oil level. Maintain the oil level within the prescribed range.
  • Check the oil for pollutants, color, clarity, and presence of contaminants. Take a sample of the oil for testing if it seems fuzzy or includes particles.
  • Utilize the sensors or gauges installed into the transformer to monitor the operating temperature. Keep a watch out for any abnormal increase in temperature.
  • Check the condition and functioning of the fans, radiators, and cooling fins.
  • Ensure sure that nothing that can restrict heat dissipation is in the way of cooling systems, such as dust, dirt, or obstructions.
  • Check for fractures and discoloration or symptoms of tracking in bushings and insulators.
  • Maintaining proper insulation may require cleaning insulators.
  • Check and tighten all electrical connections, including grounding connections and terminal nuts.
  • Keep an eye out for loose connections or overheating.
  • To ensure efficient moisture control, check the breather for the right color (typically blue to signify dryness), and replace or regenerate silica gel as necessary.
  • Check the functionality of any suitable pressure relief devices and reset them if necessary.
  • If the transformer has a gas monitoring system, examine gas levels for unusual activity or problems.
  • Keep thorough records of all maintenance tasks, including any anomalies noticed and the steps followed.
  • Ensure that all service staff receive regular training and remain acquainted with the most recent practices and safety regulations.
  • Consider setting a timetable or employing maintenance management software to track and organize normal repairs.
  • To reduce downtime, keep spare parts, oil, and necessary tools close at hand.
  • Consult a qualified transformer service provider for additional evaluation and repairs if serious problems or anomalies are found.


Given the importance of transformers in an electrical power system, a routine check of your transformers is worth it. In short, the key to better performance, higher reliability, longer durability and safe working of transformers is proper electrical transformer maintenance on a regular, daily basis. With so many intricate components and high pressure operations, scheduled maintenance of transformers can prevent your business from costly breakdowns or potential electrical hazards. 


1. What Are The Maintenance Requirements For A Distribution Transformer?

As with any other type of transformer, checking for oil level, voltage surges, connections, and regular visual and performance tests would be enough to manage a well-maintained distribution transformer.

2. Why Do Transformers Need Maintenance And Services?

Transformers work under high-pressure conditions converting high-voltage AC to lower voltages. Due to this, they may heat up faster, and they are open to the risks of electrical hazards. Hence, regular maintenance is necessary to ensure security and avoid the breakdown of a transformer.  

3. What Is Oil Needed In Maintenance Of A Transformer?

Oils inside the transformer can serve various purposes like lubrication, cooling, insulation, arc quenching, and damping.

Difference Between Surge arresters And Lightning arresters

Difference Between Surge arresters And Lightning arresters

Difference Between Surge arresters And Lightning arresters​

Surge arresters and lightning arresters are often confused interchangeably. This is mostly because both of them are used to keep your electrical applications safe and secure. With the advancement and adoption of new technologies, and mostly electrical systems, it’s important to understand what is a surge arrester and what is a lightning arrester in detail. In this article, we will go deeper and understand the surge arresters and lightning arresters in detail and highlight the key differences that make them unique to their name. 

In this article, we will explore the difference between a lightning arrester and a surge arrester, explaining what each one is and how they function and answering the frequently asked question about what is a surge arrester and what is a lightning arrester.

What Is A Surge Arrester?

These electrical devices help protect your electrical equipment by limiting the voltage surges and the current flow. In the main current line, voltage surges often occur due to various factors like lightning, power outages, temporary overvoltage, etc. This fluctuating voltage can be harmful to your appliance. That’s where surge arresters come into place.

Surge arresters help deviate the excess current and limit the voltage to prevent overpressuring your electrical appliances, protecting them from electrical outbursts or short circuits. Surge arresters can be used for various appliances, homeware, or utility substation equipment.

What Is A Lightning Arrester?

The most common and destructive voltage surges occur during lightning. Lightning can lead to high transient voltage, sparks, surge currents, etc. Thus, a lightning arrester is used to protect electrical equipment against lightning. 

A lightning arrester is generally placed higher, like on top of transmission poles, buildings, or towers. The system is well connected through ground wires and securely discharges the current using earthing. When the lightning surges, the lightning arrester absorbs the high voltage current and slowly discharges it through the ground wires, reverting back to normal. 

Lightning Arresters are generally used for heavy appliances that need protection, while surge arresters are installed to handle common voltage fluctuations. 

A Few Other Related Terms To Know

There are a few other terms you must be aware of when learning about surge and lightning arresters. Some of the major ones are:

  • Surge suppressor: It is a device installed to protect your home wiring from voltage fluctuations. A surge protector, or suppressor, is installed on the home distribution board to protect the electrical system from internal fluctuations of the contractor switch itself while also protecting it from main current fluctuations. 
  • Lightning rod: It is a metal rod installed on top of buildings, towers, and poles to protect them from lightning. If a lightning strike directly hits the current lines, it may lead to a dangerous situation involving voltage crashes, power outages, and sometimes even electrical blasts. Hence, a lightning rod, also called a lightning conductor, is installed to prevent these dangers. 

Key Differences Between Surge Arrester And Lightning Arrester

Key Differences Between Surge Arrester And Lightning Arrester

Types of Lightning Arresters

There are various varieties of arresters when we talk about lightning arresters. Some of them are:

  • Electrolytic lightning arresters 
  • Rod gap lightning arresters
  • Expulsion-type lightning arresters
  • Valve-type lightning arresters
  • Metal oxide lightning arresters
  • Oxide film lightning arresters
  • Sphere gap lightning arresters
  • Horn gap lightning arresters
  • Multiple gap lightning arresters
  • Impulsive protective gap lightning arresters
  • Thyrite lightning arresters
  • Auto valve lightning arresters

Surge Arresters Or Lightning Arresters: Which One Do You Need?

This is a contradicting question. Surge arresters or lightning arresters? After you’ve learned what is a surge arrester and what is a lightning arrester and analyzed their key differences, you pose the most important question- which one of them do you need?

To answer this, it depends on your needs and reasons. Both of the arresters are well-suited and perfect devices to protect your homes, eliminating your electrical risks. And if you’re looking around for arresters for your home security, you can get either of them installed. 

Maintenance Of arresters

Proper and dedicated maintenance of arresters is required to ensure complete security and safety. Be it a surge arrester or a lightning arrester, both require timely care to lead to proper functioning. Some of the general tips you can follow are:

  • Inspect them at least once per year or half-yearly in case of severe climatic areas or conditions.
  • Check for loose connections, as they might lead to high-resistance joints 
  • Make sure all system components are secured on their mounting surfaces
  • Keep a check record for corrosion of internal components of the arrester
  • Ensure a clean space around the arrester to avoid contamination and corrosion in the future.
  • Evaluate performance tests to check the functioning of the arresters 
  • Keep a record of ground wire connections and their functioning 

Can A Surge Arrester Be Used As A Lighting Arrester?

Did you know that surge arresters can replace a lightning arrester, but you cannot use a lightning arrester as a surge arrester? As both surge arresters and lightning arresters are designed to provide security against voltage surges and transient voltages, a surge arrester can be used as a lightning arrester in general cases.

While surge arresters are more flexible and can handle broader outages, lightning arresters are structured to handle massive surge currents through lightning strikes. Hence, surge arresters can be used in place of lightning arresters as a temporary security measure. However, lightning arresters are more suitable to be installed in the long run to ensure the effective protection and functioning of your applications. 


Both lightning arresters and surge arresters are important electrical systems designed to protect our electrical appliances from potential electrical surges and lightning damage. You can get any of them installed, as they are almost identical except for some of the key differences we identified.

However, after understanding what a surge arrester and a lightning arrester are, you must have understood how different their purpose and performance are. While you may select anyone, you must consider your needs and preferences in the first place to ensure a safe and secure environment. 


  • What Is The Difference Between Surge Arresters And Surge Suppressors? Surge arresters can deal with high-voltage surges without affecting the insulation, while surge suppressors have a low voltage capacity and cannot withstand harsh voltage surges.
  • Do Lightning Rods Attract Lightning? Yes, a lightning rod is designed to attract and absorb lightning, leading it to the ground through an electrical pathway. It helps to prevent any potential damages to buildings and structures.
  • Where are surge arresters located? A surge arrester is generally found inside the main panel board of your home electrical system. qualitybeste telefoonhoesjes tegen vallen