When it comes to maintaining reliable electrical power for your commercial, industrial, or agricultural operation, switchgear maintenance isn’t just a good idea—it’s absolutely critical. The National Fire Protection Association’s NFPA 70B standard provides the roadmap for keeping your electrical systems running safely and efficiently. Understanding these maintenance requirements can mean the difference between smooth operations and costly unexpected downtime.
Switchgear serves as the backbone of your electrical distribution system, controlling and protecting the flow of electricity throughout your facility. Just like any critical piece of equipment, it requires regular attention to perform at its best. The NFPA 70B standard outlines specific maintenance methods, testing intervals, and procedures designed to keep your switchgear operating safely and reliably for years to come.
Understanding NFPA 70B Categories
The NFPA 70B standard breaks down maintenance into different categories, each with its own purpose and timing. Online Standard testing allows maintenance teams to check certain aspects of your switchgear while it remains energized and operational. This means your business doesn’t have to shut down for routine inspections, minimizing disruption to your daily operations.
Offline Standard testing, on the other hand, requires the equipment to be de-energized. While this does mean a temporary shutdown, these tests can identify issues that might not be detectable during online testing. The comprehensive nature of offline testing makes it invaluable for catching potential problems before they become major failures.
There’s also a category called Offline Functional testing, which goes even deeper into verifying that all mechanical and electrical components are working as designed. Think of it as a comprehensive physical examination for your electrical equipment.
The Power of Infrared Thermography
One of the most valuable tools in modern switchgear maintenance is infrared thermography. This technology allows technicians to see heat patterns in your electrical equipment without having to shut anything down. Hot spots often indicate loose connections, overloaded components, or other issues that could lead to equipment failure or even fires.
The beauty of infrared thermography lies in its non-invasive nature. Your operations can continue normally while technicians scan your switchgear for potential problems. According to NFPA 70B, this type of inspection should be performed annually, making it a cornerstone of preventive maintenance programs.
What makes infrared inspection so effective is its ability to detect problems in their early stages. A connection that’s beginning to loosen will start generating excess heat long before it fails completely. Catching these issues early allows for planned maintenance rather than emergency repairs, saving both time and money.
Ultrasonic Detection: Listening for Trouble
Another advanced maintenance technique outlined in NFPA 70B is ultrasonic detection, particularly useful for identifying arcing and corona discharge. These electrical phenomena often produce high-frequency sounds that are inaudible to the human ear but can be detected with specialized equipment.
Arcing within switchgear is a serious concern that can lead to equipment damage, fires, and safety hazards. Corona discharge, while less immediately dangerous, can indicate insulation problems that will worsen over time. Both issues are best addressed before they escalate into major problems.
The annual testing interval for ultrasonic detection makes it a practical addition to your maintenance routine. Like infrared thermography, it can often be performed while equipment remains energized, minimizing operational disruption while maximizing the information gathered about your system’s condition.
Contact Resistance Testing: Ensuring Solid Connections
Contact resistance testing focuses on one of the most critical aspects of switchgear operation: the quality of electrical connections. Poor connections are responsible for a significant percentage of electrical failures, making this type of testing extremely valuable for preventing problems.
This testing method measures how much resistance exists across bolted or breaker contacts. Higher than normal resistance indicates problems such as corrosion, looseness, or contamination that could lead to overheating and failure. The NFPA 70B standard recommends this testing every three years for critical applications and every five years for typical installations.
Understanding when to test is important, but knowing what the results mean is equally crucial. Resistance measurements that fall outside acceptable ranges indicate the need for corrective action, whether that’s cleaning contacts, tightening connections, or replacing components entirely.
Insulation Resistance Testing: Protecting Against Breakdown
Insulation resistance testing, often called “megger testing,” evaluates the condition of insulation materials within your switchgear. This testing is particularly important because insulation breakdown can lead to ground faults, short circuits, and other dangerous conditions that pose risks to both equipment and personnel.
The test involves applying a DC voltage to the insulation and measuring how much current flows through it. Healthy insulation should allow very little current to pass, while deteriorated insulation will show increased current flow. This testing should be performed every three years for critical systems and every five years for typical applications.
Environmental factors play a significant role in insulation degradation. Moisture, dust, chemical contamination, and temperature extremes can all accelerate the breakdown of insulation materials. Regular testing helps identify deterioration before it reaches dangerous levels. See our posts about environmental conditions here and here.
Mechanical and Electrical Function Verification
Beyond electrical testing, NFPA 70B emphasizes the importance of verifying that all mechanical and electrical functions operate as designed. This includes checking that circuit breakers open and close properly, that interlocks function correctly, and that all safety systems respond appropriately.
This type of testing typically requires the equipment to be taken offline, as it involves actually operating various components to ensure they work correctly. The testing interval is more frequent than some other methods—annually to every three years—reflecting the critical nature of these functions.
Mechanical components in switchgear experience wear over time, and electrical components can drift from their original settings. Regular functional verification ensures that when you need your protective systems to operate, they’ll respond as intended. This testing often reveals issues that aren’t detectable through other methods.
Partial Discharge Testing: Advanced Problem Detection
For enhanced or critical applications, NFPA 70B includes partial discharge testing as an option. This advanced technique can detect very small electrical discharges within insulation systems—discharges that might not show up in standard insulation resistance testing but could indicate developing problems.
Partial discharge testing is particularly valuable for medium and high voltage switchgear, where insulation integrity is absolutely critical. The test can identify issues such as voids in insulation, contamination, or manufacturing defects that could eventually lead to complete insulation failure.
While not required for all installations, partial discharge testing provides an extra level of insight into equipment condition, especially for critical applications where unexpected failures would have severe consequences for operations or safety.
Planning Your Maintenance Schedule
Creating an effective maintenance schedule based on NFPA 70B requires balancing operational needs with recommended testing intervals. The standard provides flexibility by offering different intervals for critical versus typical applications, recognizing that not all installations have the same reliability requirements.
Consider your operation’s tolerance for downtime when planning offline testing. Some facilities can schedule maintenance during regular shutdown periods, while others may need to coordinate more carefully to minimize operational impact. The key is developing a schedule that meets NFPA 70B requirements while working within your operational constraints.
Documentation plays a crucial role in effective maintenance planning. Keeping detailed records of all testing results, maintenance activities, and equipment changes helps identify trends and plan future maintenance needs. These records also demonstrate compliance with industry standards and can be valuable for insurance and regulatory purposes.
The Business Case for Proactive Maintenance
While switchgear maintenance requires investment in both time and money, the cost of neglecting maintenance far exceeds the cost of staying current with NFPA 70B recommendations. Unexpected equipment failures can result in extended downtime, emergency repair costs, and potential safety incidents that could have been prevented through proper maintenance.
Regular maintenance also extends equipment life, allowing you to get maximum value from your electrical infrastructure investment. Well-maintained switchgear can operate reliably for decades, while neglected equipment may fail prematurely, requiring expensive replacement years ahead of schedule.
From a safety standpoint, proper maintenance protects your employees and facilities from electrical hazards. Electrical incidents can result in serious injuries, property damage, and business interruption that extends far beyond the immediate cost of repairs.
Working with Qualified Professionals
While understanding NFPA 70B requirements is valuable for any facility manager, implementing these maintenance procedures requires qualified electrical professionals with specialized training and equipment. The complexity of modern switchgear and the safety hazards associated with electrical testing make professional expertise essential.
When selecting a maintenance provider, look for technicians with appropriate certifications and experience with your type of equipment. The investment in quality maintenance services pays dividends through more reliable operations, better safety performance, and longer equipment life.
Remember that maintenance is not just about compliance with standards—it’s about ensuring your electrical systems support your business operations reliably and safely. By following NFPA 70B recommendations and working with qualified professionals, you can maintain the electrical infrastructure that keeps your business powered and productive.
This blog post was created by Ag Electric Services, LLC, an Arkansas based electrical and general contractor serving the following areas of Central and Eastern Arkansas: McCrory, Augusta, Newport, Wynne, Brinkley, Des Arc, Forrest City, Hickory Ridge, Cherry Valley, Tuckerman, Jonesboro, Searcy, Pangburn, Heber Springs, Greers Ferry, Rosebud, Quitman, Romance, Kensett, Georgetown, Cabot, Beebe, El Paso, Hickory Plains, Carlisle, Lonoke, Little Rock, North Little Rock, Sherwood, Jacksonville, Maumelle, Conway, Mayflower, Vilonia. If you would like more information about the services we provide, please click “Services” in the main menu, or contact us through the online information request form on the “Contact Us” page.