Lightning Arrester: A Protective Device For Your Electrical Systems

When lightning strikes, it creates a voltage surge. Both cloud-to-cloud lightning and cloud-to-ground lightning can result in voltage surges.  Now, this voltage surge wants to equalize itself as soon as possible, and it can do so by short-circuiting your electrical equipment. For example, it can either directly hit your house or strike on a cable line that passes over your home. Thus, a simple way to protect from this surge is to give it a safe path to neutralize. Therefore, you need to have a lightning arrester.

Image: arrester house lightning icon

Methodology to Suppress Lightning and Voltage Surge

To neutralize the surge in voltage, you can adopt one or all of the different ways mentioned here:

• You can create a reliable grounding system for your electrical equipment. Otherwise, the electricity will look for the microchips in your electrical systems. For a sound grounding system, put several grounding rods in the soil around your home.  Make sure that rods are UL approved and have a connection with heavy and solid copper wire. Try not to use clamps as they corrode over time. Corrosion increases the resistance of copper wires. 
• Other than the grounding system, you can install a lightning arrester in your electric service panel. A lightning arrester can stop large voltages that affect power lines and take the surge voltage to the grounding wire. However, without enough grounding wires and rods, an arrester will fail to do its job.
• Apart from the above two, you can install a “point of use” surge suppression device. You can also call them transient voltage surge suppressors. However, you have to use this along with the grounding system and arresters, and it can just stop the surge missed by grounding wires and lightning arresters. 

How Does a Lightning Arrester Work?

It has two terminals; a high-voltage and a ground one.  You have to install a surge arrester near the point of entry of voltage. This can be your electrical panel or a generator. After installation, if the lightning strikes, the device activates itself. However, you must know that it does not stop the lightning but diverts it to a safe route. It is like a home defense system that protects electrical devices from the drastic effects of high currents.

Image: lightning arrester system

You can find lightning arresters in power transmission and telecommunications systems. In such scenarios, there are small arresters known as surge protectors. These devices allow the average current to flow in the machines. However, when there is a high voltage, it takes that high-voltage current to the ground safely. 

Types of Lightning Arresters

There are several types of lightning arresters available.

Expulsion types: You can also call it a protector tube. You can use this arrester in systems that operate at a voltage of not more than 33kv. It mainly consists of three parts:

• A fiber tube that evolves the gas effectively. The tube has two electrodes; an upper one connects to the rod gap, and a lower one connects to the ground.
• An isolating external series gap
• A spark gap in the fiber tube.

When a surge voltage arises over the expulsion tube, it spans the series gap. As a result, arc forms between the electrodes of the box. Now, this arc causes the fibrous material in the tube to evaporate in the form of gas. This gas passes through the vent. One of the electrodes is hollow; it allows the gas to pass and extinguish the arc, similar to circuit breakers. 

Valve-type lightning arresters:

You can also call them non-linear diverters. Unlike, expulsion type, you can use this on systems with high voltage operations. This arrester has a divided spark gap with a resistance in series, and the opposition has non-linear features. The spark gaps, non-linear resistors, and coil units are in a porcelain container.

The spark gap has several gaps connected in series. You will find two electrodes with space in each hole. There are some resistors across the gaps to linearise the voltage. These are grading resistors. During average voltage, you will see no spark. However, when there is surge voltage, the air between the gaps creates an arc between the electrodes. Now, this arc takes surge current to the ground with the help of non-linear resistors.

Gap-less metal oxide arresters:

You can call them zinc-oxide diverters or gapless surge diverters. Here the base material is zinc, and the oxide is Zinc oxide, and this material is semiconducting and has a coating of insulating oxide.

Power fills a disc-shaped structure. A ceramic housing having sulfur hexafluoride encloses this disc. So, the arrester has a barrier at the zinc oxide edges. In normal conditions, this potential obstacle stops the flow of current. However, the obstacle breaks in case of a voltage surge, and the high voltage current passes safely to the ground.

Image: technician installing lightning protection system rod on top of a building.

Classification of lightning Arresters

Based on the nominal discharge current, lightning arresters are divided as under:

Station class: You will find them in electric power stations. Among all the arresters, this type gives the best discharge voltages. It can handle high energy and can withstand the highest fault current. You can find this in ratings of 3 to 684kv. The cantilever strengths of station lightning arresters can vary depending on their applications. 

Intermediate class: They also offer suitable discharge voltages and high fault current bearing capacity. Usually, their ratings range from 3 to 120kv.

Distribution arresters: You can find them on transformers. These have voltage ratings between 1 to 36kv. You can find three categories in this; namely light-duty, standard duty, and heavy-duty.

There is a riser pole arrester in heavy-duty LA (lightning arrester) which protects from the surge voltage faced by underground cables and other equipment. High lightning applications use Heavy-duty LA. On the other hand, low lightning applications generally use regular duty LA.

Secondary arresters: you can use these arresters to protect businesses and homes from lightning strikes. These have voltage ratings below 1000V, and these arresters mainly protect from the secondary surge and reduce the failure rates of the transformer.

Ldentification of Surge Arresters

You can identify a surge arrester based on information available on the nameplate or rating plate. Identification is based on the: 

• Rated voltage
• Rated frequency
• Nominal discharge current
• Long-duration discharge class
• Manufacturer’s name or trademark
• Type of arrester

Standard ratings of a Lightning Arrester

When you pick a lightning arrester, your objective should be to choose the lowest-rated arrester. These arresters offer considerable protection from the insulation of the equipment.

Rated voltage: A lightning arrester must bear the maximum continuous operating voltage or MCOV. Any leakage current that passes through the arrester limits itself to its specific rated value on this voltage. An arrester’s rated voltage depends on 

• System line-to-line voltage
• System grounding method
• Type of lightning arrester used

Make sure that the voltage rating is more than the highest sound phase to ground voltage.

Rated frequency: The standard rated frequencies of lightning arresters are 50Hz and 60Hz.

Rated nominal discharge current: This is the discharge current that an arrester picks during discharge of surge current. 

System Voltage	Normal discharge current
Above 66kv	10KA
Greater than 22kv and less than 66kv	5KA
Less than 22 kV	1.5 or 2.5KA

Service Condition of lightning Arrester

You can use a lightning arrester for regular operation under normal service conditions.

• Ambient air temperature should be within -40^oC- +40^oC
• Altitude should not be more than 1000m
• Solar radiation
• The frequency of AC power supply should be within 48Hz-62Hz
• Wind speed should be less than or equal to 34m/s

Sometimes, surge arresters need to work in abnormal working conditions. For this, the manufacturer has to design its structure based on its applications. The abnormal service conditions may include:

• Temperature less than -40^oC or more than +40^oC
• Altitudes higher than 1000m
• Frequency level above 62Hz or below 48Hz
• High wind speed more than 34m/s
• Unusual transportation or storage situation

Why Should you Install a Lightning Arrestor

Here is a list of advantages that a lightning arrestor offers.

• Prevents property damage: When lightning strikes, it can damage the exterior structure of the building. If you are at a location where you face regular lightning, you can prevent this damage. For this, you need to install a lightning arrestor on the exterior of your property.
• Prevents line damages: Lightning can damage the wires and cables outside your home. As a result, there may be significant damage in the electrical systems. Investment in lightning arresters is way less expensive when compared to that damage. Further, damaged wires can lead to serious consequences, including the death of a person. 
• Easy to use: A simple lightning arrester is quite easy to install and use. Indeed, this is one of the best solutions when compared with others. You just need to invest some money, call an electrician and enjoy its benefits.  
• Avoid outlet surge: If you install a lightning arrestor inside a building, it can prevent an outlet surge. For this, you can pick from simple to complicated devices. No matter what you pick, all these devices will protect you and your devices from all types of surges.
• Prevent electromagnetic interference: Most of the electricity filtering devices used in homes have lightning arresters along with other features. These small-scale arresters prevent electromagnetic interference in your electrical devices when a surge arises.

Difference between Surge Suppressor, Surge Arrester, Lightning Rod, and Lightning Arrester 

You often use these words for the same purpose. However, these terms are different based on what kind of systems you use and how you want to protect them.

• Surge arrester: With this, you can protect electrical devices and installations from transient voltage. This voltage may occur due to a spark, lightning, short circuit, or electrical faults. You can install a surge arrester inside the panel to cancel out the voltage surge.
• Lightning arrester: With this, you can protect electronic devices and circuits from lightning with high transient voltage surges. You have to install them outside your home ground to cancel out the effect of lightning.
• Surge suppressor: You can call it a surge protector or transient suppressor. You need to install it on the home panel to protect devices from voltage spikes.
• Lightning rod: You need to install this device at the top of your home or transmission towers. These rods provide an easy path to lightning towards the ground. With this lightning rod, buildings are protected from lightning surges.

 Image: lightning rod against a dark cloud sky

Recommended Equipment for Outdoor Antenna Lightning Protection

IIf you use an outdoor antenna or Ethernet cables, you must install a TV antenna lightning arrester kit. These are some of the options.

• Lightning Arrester for LTE, Wi-Fi, and LoRa- Bolts of lightning-induced surge current and over-voltage. You can secure your transceivers and N-type antenna by installing this surge protector. Also, you can secure your radio communication systems through the ham radio lightning arrestor. Similarly, a polyphase lightning arrestor also protects your sensitive equipment such as radio.
• Lightning Arrester for GPS antenna: You can connect this device between the antenna and GPS receiver. As a result, it protects transceivers against surge current and transient voltage.
• Antenna Feeder line: With a coaxial lightning arrestor, you can get optimal coverage by positioning gateway antennas in a better way.

Image: antenna cable

• Single surge protective device: You must use this protective device for category 6 and category E cables. You can use this in office or industry wiring and other telecommunication systems.
• Ethernet cabling: For this, you can use CAT5 Ethernet Cable as an Ethernet lightning arrestor. This cable connects the PoE injector, Ethernet/POE port, Ethernet SPD, and the switch.

Conclusion:

So, now, you can see how a lightning arrester can protect your valuable devices and electrical systems. And for any help related to your outdoor antenna lightning protection, you can contact Cloom, and we deal in high-quality cable assemblies and wiring harnesses.