What is a Lightning Arrester

A single surge can damage your equipment, but if you use a lightning arrestor, it saves your equipment from surges by directing high-voltage surges into the ground. So, in this blog, you will analyse what is a lightning arrestor? How it works, its types, and many more are comprehensively. Stay protected and keep learning!

1) What is a Lightning Arrester?

“As the name suggests, a lightning arrester arrests the lightning. Basically, it is a safety gadget built into electrical circuits so that any sudden, high-voltage surge from a lightning strike is sent safely to the ground.”

In simple words, a lightning arrester is a small device present in the electrical system to shield equipment from lightning strikes. When a surge arrives, the arrester redirects that dangerous extra voltage straight into the ground, like a safety valve for electricity.

Well, you'll see these protectors on power poles, at transformers, and inside substations. Generally, when lightning strikes, it produces a sudden high voltage surge, this surge causes damage to the electrical systems. So, a lightning arrester gives the surge a resistance path to the ground.

Why Lightning Arresters Matter

Today, we lean on electricity for almost everything we do. Even a single lightning strike can damage the whole electrical system, so it requires the costs of thousands to repair. That’s why lightning arresters matter.

Furthermore, they are used in homes, factories, and electrical grids to minimise the risk of damage. Moreover, lightning arresters are present at the site where high voltage surges can occur. Apart from this, you will see them installed at the power poles, building entry points, transformer terminals, and switchgear equipment.

Most importantly, the lightning arrester also matters because it responds instantly. When a surge is produced, it quickly responds to prevent damage. Without a lightning arrester, your electrical system is always at a high risk.

2) How Does a Lightning Arrester Work?

Alright! By knowing what a lightning arrester is, now, a question can arise in your mind: How does a lightning arrester work, right? Great question,  so let’s discuss its working:

Normal Operation

The very first thing is that in normal conditio,ns lightning arresters remain inactive. And, it is connected between the electrical system and the ground, but it does not stop the flow of electricity. Moreover, the voltage across the terminals of the lightning arrester is below its breakdown voltage, so current does not flow through it.

During a Surge

If lightning or another high- voltage strikes occur then the voltage across the terminals of the lightning arrester increases. The components of lightning arrestors such as spark gaps or metal-oxide arresters are made to conduct when voltage exceeds a specific threshold.

So, when voltage exceeds the voltage breakdown, the arrestor suddenly changes to a low resistance state and becomes active.

Diverting the Surge

At this point, the arrester diverts the high voltage surge to the ground. So, electrical equipment remains safe from any damage.

Returning to Normal

Once the surge clears, the arrester comes back to its normal condition of high resistance as quickly as possible. Hence, the electrical system resumes standard operation without missing a beat or needing a manual reset.

3) Types of Lightning Arresters

It is also significant to discuss the types of lightning arresters so that you can pick the right one for your electrical system. So, let’s have a look at the types of lightning arrestors!

i) Rod Gap Arrester

Rod gap arrester is the simplest type of lightning arrester. It is designed as the two metal rods are placed with a small air gap between them. One rod is connected to the electrical system and another one is connected to the ground.

Significantly, when a surge occurs the high voltage surge goes into the ground. Hence, it is a simple and low cost type of arrester. But, the bad news is that it cannot control the lightning surge in the dusty or humid environment. Hence, it is mostly used on rural or older systems.

ii) Sphere Gap Arrester

Another type of arrester is sphere gap arrester, its working principle is the same as the rod gap arrester. But, there is a difference between two sphere gaps instead of metal rods.

Moreover, the curved shape of sphere gap arrester aids to create more controlled discharge way. Furthermore, it usually used in laboratories or testing setups. Most importantly, it requires regular inspection and is sensitive to dirt and weather.

iii) Valve-Type Arrester

Well, the valve-type arrestor mixes spark gaps with blocks of non-linear resistors. When a voltage surge occurs, the gap fires open, and the surge runs into the resistors, which control the flow of current.

After the surge leaves, everything switches back to normal. Moreover, Valve-style arresters are tougher than simple gap arrester but is is mostly replaced by newwer designs.

iv) Metal Oxide Arrester (MOA)

The Metal oxide arrester is the newest and most trusted surge protector in the market. Inside, layers of zinc oxide replace the old spark gaps. Because of this design, it reacts to voltage surges almost instantly.

Significantly, MOAs need no upkeep, last for decades, and protect equipment extremely well. Moreover, you'll find them wired into homes, factories, substations, and the biggest power grids.

v) Expulsion-Type Arrester

An expulsion arrester type pairs a spark gap with a gas filled tube. When a surge produes, then pressure is builds which bursts the gas out, and sends the extra voltage safely to ground. And, this type is usually used in medium voltage overhead lines. The good news is that it costs little but when big surges happened, it needs to be replaced.

vi) Polymer Lightning Arrester

This modern version of the metal oxide arrester is covered with a tough polymer shell. Moreover, it is lightweight, weather-resistant, and safe for outdoor use. Well, it is best for harsh environments because the polymer resists cracking and corrosion.

4) Lightning Arrester vs Surge Arrester

Alright! Lightning arresters and surge arresters both safeguard the electrical system from sudden high-voltage surges. Still, don't mistake one for the other. These two are quite similar at first sight, but each unit has its own design, job, and use. Let's sort out the difference in simple terms!

• What Is a Lightning Arrester?

You know well that a lightning arrester shields equipment from the full force of a direct lightning hit. You will usually spot it mounted outside, close to transformers, poles, or substations.

As we already discussed, when lightning hits the lines, the arrester redirects the high voltage straight into the ground. That quick response stops equipment from melting, burning, or breaking. Most importantly, Lightning arresters mainly serve high-voltage outdoor networks.

• What Is a Surge Arrester?

Conversely, a surge arrester is designed to safe the electrical equipment from internal surges. Moreover, usually these surges come from the switching operations, motor startups or faults inside the system.

Furthermore, these are usually used inside homes, offices, and factories to protect sensitive electronics and gadgets. And, these units are compact and easier to fit into standard panels.

• Key Differences

Let's break down how the two devices differ:

• Source of Surge: Lightning arresters handle surges created by real lightning strikes. In contrast, Surge arresters deal with smaller spikes that come from motors, generators, or the grid.

• Location: Normally, lightning arresters are mounted outdoors, mostly on the top of buildings or power poles. Conversely, Surge arresters are placed indoors near computers, TVs, or any sensitive equipment.

• Voltage Level: Lightning arresters are built for high-voltage lines. But, Surge arresters handle low- or medium-voltage circuits inside an electrical system.

• Purpose: A lightning arrester sends huge strike energy safely into the ground. On the other hand, A surge arrester blocks and diverts the surges before they go into your devices.

• Design: Lightning arresters are heavy, weatherproof units. Conversely, Surge arresters are lightweight and fit inside power strips or panels.

5) Lightning Arrester vs Lightning Rod

Lightning arrester and a lightning rod both deal with lightning, so how can they be different, right? Well, the truth is, each tool protects a building in its own way and works on a separate part of the structure. Let us break down what sets them apart.

• What Is a Lightning Rod?

A lightning rod is a simple metal rod or conductor fastened to the highest point of a building, home or radio towers. Its job is to stand ready and grab any strike of lightning that comes close. The rod then guides that huge electrical surge down a heavy wire and into the ground, where it releases safely.

Hence, these aids prevent fires, structural damage or harm to people inside the building. Generally, a lightning rod is a passive system to provide a safe way for lightning to reach the earth.

• What Is a Lightning Arrester?

A lightning arrester is not the same as a lightning rod. While a rod keeps a building safe above, the arrester guards the gear inside. You'll find arresters wired into power grids, often at substations, pole tops, or transformer pads.

What happens is that when a bolt or a huge voltage spike hits the line, the arrester jumps into action. It quickly diverts the extra energy down to the ground, so sensitive circuits stay safe. Arresters work fast and automatically.

• Key differences

The key difference between the lightning rod and lightning arrestor is discussed below:

• Function: Well, the rod shelters the physical structure. But the arrester shields the electrical devices present inside that structure.

• Placement: Rods are present at the top of roofs and on tall structures. Conversely, arresters are attached close to transformers, poles, or circuit panels.

• Working Method:  Significantly, a rod holds the lightning directly and guides it to the ground. On the other hand, a lightning arrestor holds the voltage surges and quickly redirects them into the ground.

• Application: Rods used in homes, barns, and radio towers.  In contrast, Arresters protect power grids, substations, and factory machines.

• Protection Type: A lightning rod guards your building from fire and heavy damage.  But A lightning arrester shields all the gadgets and wires inside.

6) Delixi Lightning Arrester

Delixi Electric makes dependable lightning arresters for medium and high-voltage lines between 11 kV and 33 kV. These units fit into Delixi's wider power gear range, which features outdoor load switches, drop-out fuses, composite insulators, and other key parts for smooth grid operation.

• 33 kV Lightning Arrester

Delixis 33 kV lightning arresters stand ready to stop severe surges from lightning strikes or routine switching. These are built for tough outdoor use; they resist moisture, dust, and extreme heat or cold. You will typically find them near transformers, at circuit breakers, and mounted on power poles inside substations.

Delixi Electric lightning arresters deliver:

• Quick response to high voltage surges
• Durable construction for a harsh environment
• Compliance with international safety standards

• 11-33 kV Lightning Arrester

Delixi makes 11-33 kV lightning arresters for overhead lines and distribution systems. Moreover, these are designed for easy installation on outdoor structures such as poles and cross-arms.   

Key features

The features of 11- 33kV lightning arrestor are:

• compact size that fits tight work sites
• Insulation rated to handle 11-33 kV
• Consistent protection across multiple voltage levels

Why Choose Delixi Arresters?

Delixi stands out in power transmission because its arresters join a broad lineup that includes switchgear, transformers, fuses, and insulators. When you pick Delixi, you gain:

• support from one trusted partner
• Proven equipment designed to control real-world stresses
• Products built for simple integration with high-voltage systems

You can contact Delixi right now by clicking here.

7) FAQ

1. What is the symbol of a lightning arrester in electrical diagrams?

In most diagrams, the symbol of lightning arrestor looks like a vertical line with a zigzag or curved path leading to ground, clearly showing how it channels dangerous surges away from equipment.

2. Why is a lightning arrester used for transformers?

A lightning arrester for transformers draws away big voltage spikes from lightning or sudden switching, keeping the units safe and saving money on repairs.

3. What is a high-voltage lightning arrester, and when is it needed?

A high-voltage lightning arrester protects electrical systems above 1,000 volts, like substation systems, long transmission wires, and large factory grids, stopping huge surges before they ruin equipment.