How to Replace a Faulty Lightning Arrester

How to Replace a Faulty Lightning Arrester


Replacing a faulty lightning arrester is an important electrical safety task that homeowners should not take lightly. Lightning arresters, also known as surge arresters, provide critical protection to your home's electrical system by diverting lightning strikes and power surges safely to ground. However, arresters can wear out over time. When that happens, it's crucial to replace them promptly to maintain protection.

In this guide, I will walk through the complete process of replacing a faulty lightning arrester in depth. I'll cover how to identify when an arrester is faulty, selecting the right replacement, safely disconnecting the old unit, installing the new arrester, and testing it is working properly. Follow along to learn how to do this job safely and ensure continued protection for your home.

Identifying a Faulty Arrester

The first step is determining if one of your home's lightning arresters needs replacing. Here are the signs of a faulty unit:

Physical Damage

Carefully inspect the arrester housing. Look for any cracks, holes, burn marks or other visible damage. Any physical damage means the arrester can no longer provide full protection.


Check for discolored sections on the arrester or burn marks. This can indicate the arrester has diverted surges but is now weakened. For example, a gray or white porous surface means the interior components have been damaged.

No Ground Wire

Verify the ground wire is intact. Lightning arresters must be grounded to divert energy. If the ground wire is disconnected or damaged, the arrester cannot function properly.

Frequent Power Issues

Consider any appliance damage or electrical issues. If you've had frequent problems like bulbs blowing out or electronics getting damaged, it may mean your arrester is faulty and surges are getting through.

If you notice any of these warning signs, it's best to be proactive and replace the arrester. I would not ignore these problems since a faulty arrester leaves your home vulnerable.

Choosing the Right Replacement Arrester

Once you've determined a faulty arrester needs to be replaced, the next key step is selecting the proper new arrester. Here are the key factors to consider:

Electrical Configuration

Energy Rating

Enclosure Type



Selecting a directly compatible arrester makes installation faster and ensures optimal reliability. Check the manufacturer’s specifications to match all criteria.

Disconnecting the Old Arrester

With the new arrester ready, it's time to safely disconnect the faulty old one. This step is critical - always take precautions when working with electrical systems:

Safety first! Follow all guidelines for working with electrical systems. I cannot emphasize enough how critical it is to fully disconnect power and lock out the panel before disconnecting the arrester. Take no risks when replacing these important protective devices.

Installing the New Arrester

Once the old arrester is removed, it's time to install the new replacement unit:

Take care when installing the replacement to guarantee all safety guidelines are followed.

Testing the New Arrester

Once installed, the new arrester should be tested to verify proper installation and operation:

Ground Continuity Test

Resistance Test

Voltage Test

Under Load

Visual Inspection

Catching any issues now ensures your home's electrical system remains protected. Replace the arrester immediately if testing reveals any problems.


Replacing a lightning arrester is an important task that requires care, safety preparations, and attention to detail. Follow these steps:

Never ignore a potentially faulty arrester - replacing them promptly ensures ongoing protection against surges. Follow this guide to complete this important safety task correctly. Your home's electronics and electrical system will remain safe from lightning strikes and voltage spikes.