Switchgear testing or evaluations are critical in ensuring the safety and reliability of electrical systems. This is especially true for industrial, commercial, and utility environments. That said, all sectors must have reliable electricity installations. 

A switchgear combines electrical disconnect switches, circuit breakers, and fuses to protect and control electrical equipment. Your building’s switchgear should be regularly tested to ensure it works properly and prevent potential failures that could cause a dangerous situation.

If you have a switchgear test coming up, whether for maintenance or compliance reasons, it is always good to be well prepared. Keep reading to find out how to prepare and ensure the process goes smoothly. 

Why Is Switchgear Testing Important?

Switchgear testing confirms that all the components that should work do. The testing process can also detect faults, wear, or damage that may cause a problem later. 

Crucially, testing can ensure that switchgear meets the standards and guidelines set out by official bodies such as the National Fire Protection Association (NFPA) and the Institute of Electrical and Electronics Engineers (IEEE).

Moreover, testing can help prevent electrical hazards that may endanger other equipment or your workers. 

Regular switchgear testing can extend the lifespan of your equipment and ensure that your electrical system continues to operate safely and efficiently. 

Review Testing Requirements and Standards in Preparation for a Switchgear Test

The best way to prepare for a switchgear test is to educate yourself about the relevant testing standards and requirements. In the U.S., these standards are dictated by the abovementioned organizations and the Occupational Safety and Health Administration (OSHA).

It is important to familiarize yourself with the standards that apply to your building and equipment, but several key standards should generally be considered. 

• NFPA 70B: This standard provides guidelines for electrical equipment maintenance, including switchgear.
• IEEE C37.09: This outlines testing procedures for AC high-voltage breakers used in switchgear. 

OSHA regulations and standards may require specific safety protocols during testing to protect workers from electrical hazards. 

What Does Switchgear Testing Entail?

Your building’s switchgear protects it against electrical problems. If your system is larger, you will have more switchgear components typically grouped as a switchgear lineup. 

Testing switchgear involves looking for deterioration caused by corona discharge or moisture. 

Requirements for Switchgear Tests

The requirements for switchgear tests also include several mandatory tests outlined by the IEC 62271-100 standard. This standard dictates testing requirements for medium- and high-voltage three-phase AC circuit breakers operating at 50- or 60-hertz frequencies. 

Sometimes, more tests and inspections are needed to ensure that switchgear meets standards and works as intended. 

Some of the mandatory tests include: 

• Mechanical operation test: This routine test checks whether all switchgear components have been correctly fitted and work well. It also checks the mechanical operating times at different voltages to ensure that all mechanisms function as they should. 
• Insulation resistance test: This test involves applying a voltage to switchgear insulation. This helps determine the megaohm value of the insulation’s resistance. 
• High-potential test: This test involves using a high voltage on circuit breakers. It confirms that the insulation is of good quality and in good condition. The high-potential test also monitors leakages and should be done after the necessary repairs and cleaning. 

Preparing for a Switchgear Testing Procedure

You should prepare your staff for a switchgear test by getting the necessary materials together and checking your equipment history. Let your employees know when you are doing this, and give them a test schedule so they know what is happening. 

Disconnect everything before testing commences. Make sure all safety measures are followed before doing an initial inspection and cleaning. If essential parts need replacing, do so. 

If your employees experience issues after the test, ask them to write a report so you can compile all the problems in one document.

What Types of Testing is Done on Switchgear?

Switchgear tests check for more than just the physical condition of equipment. It also ensures that the equipment works and will continue to function as needed. If you have MV and LV switchgear components, they will likely be subjected to the following tests:

• Contact resistance: This refers to the contact resistance between conductors
• Functional: This test checks for overall unit function.
• Auxiliary circuit insulation test: This test measures insulation for low-voltage units
• AC insulation test: This is required to measure insulation between open contacts, lines, and ground. 
• Tightness test: This checks the tightness between each breaker connection. 

When Should Switchgear Be Tested?

Your building’s switchgear should ideally be tested once a year. The more consistent your testing schedule, the better your switchgear system will work. 

However, it is also important to perform regular checks to see whether any of the components are discoloring or if debris is building up. 

When your annual test is done, and the results are poor, you should address all the fixes immediately. If you do not resolve the issues, your system will eventually break down. 

Additionally, you must check all critical elements of the switchgear system and manually test them for function. These elements include:

• Switches
• Insulation
• Disconnect points
• Termination tightness
• Wiring
• Circuit breakers
• Thermostats
• Temperature control panels
• Mounting bolts

Remember to re-energize your switchgear when all the tests are done and the necessary repairs are completed. Your facility will have protocols for re-energization, which you should follow carefully. When the system is up and running again, it is crucial to monitor the performance to ensure everything keeps working. 

If you notice anything unusual, including readings, sounds, or smells, take immediate action to address these issues. 

Switchgear Testing Can Be Complex But Is Necessary

There is no shortcut when it comes to switchgear testing, maintenance, and fixes. If your building’s switchgear is in poor condition, it will impact the safety of the building itself. If the switchgear is never tested or maintained, the circuit breakers can malfunction.

This could lead to arc faults or flashes that will damage your business assets, and that could potentially seriously injure your employees. It is simply not worth the risk, especially when it comes to human lives. 

So, have your building’s switchgear inspected so you can ensure a safe and efficient electrical infrastructure for everyone. 

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