How to Replace a Faulty Lightning Arrester

Introduction

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.

Discoloration

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

• Match the voltage and type of your electrical system. Arrester types include AC, DC, and communication line models.

• For example, a 120V AC model would be used in a standard household electrical panel.

Energy Rating

• Select the appropriate joule rating. This indicates how much surge energy the arrester can safely divert.

• Higher joule ratings provide more protection, such as a 100kA model for a lightning prone area.

Enclosure Type

• Choose the right enclosure like indoor, outdoor, weatherproof, etc. It must be suitable for the location.

• For outdoor locations, select weatherproof NEMA rated enclosures.

Size

• Match the physical size of the existing arrester. The new one should fit seamlessly into the space without modifications.

Certifications

• Look for units certified by UL or other standards. This indicates they meet established safety and performance standards.

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:

• Disconnect the power to the electrical panel and use a multimeter to confirm it is fully de-energized.

• Carefully remove any covers or barriers to access the arrester and surrounding wires.

• Double check wires are de-energized before disconnecting them.

• Disconnect the ground wire first, then the hot/live wire. Remove any mounting hardware to fully detach the arrester.

• Inspect all connections points and wiring to ensure there is no damage before installing the new arrester. Replace any deteriorated wires.

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:

• Secure the new arrester in the exact same location as the old one if possible. Use any existing mounting points or hardware.

• Connect the ground wire to the arrester's ground terminal first, ensuring a tight and secure connection.

• Next, connect the hot wire to the live terminal on the arrester, again ensuring the connection is tight.

• Double check connections to confirm they are clean, secure, and in the right locations.

• Replace any panels or covers. Make sure the arrester is protected but still accessible.

• Restore power to the panel and ensure normal operation. Do not restore power until all connections are complete.

• Visually verify the new arrester shows no signs of damage, overheating, or other issues.

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

• Use a multimeter to test for continuity between the arrester's ground terminal and the panel enclosure or grounding electrode. There should be 0 ohms resistance.

Resistance Test

• Measure the resistance between the line and ground terminals on the arrester using a multimeter. Consult manufacturer specs, but it should show high resistance in the megohm range.

Voltage Test

• With power on, measure the voltage at the line terminal. It should match your system voltage, such as 120V.

Under Load

• Check the arrester while electrical loads are energized to ensure proper operation.

Visual Inspection

• Do a final visual check for any signs of damage, burns, arcing or melted plastic. This could indicate improper installation if observed.

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

Conclusion

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

• Identify faulty arresters by looking for signs of damage.
• Select an appropriate replacement arrester that matches your electrical system.
• Take safety precautions like disconnecting power before removing the old arrester.
• Install the new arrester securely in the proper location.
• Perform tests to verify proper installation and operation.

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.