Emergency Power System Maintenance: Maintaining Transfer Switches

A transfer switch transfers the building power load from utility feed to generator feed in the event of a power outage. Regardless of the emergency generator a building contains, its operation depends on a transfer switch. To ensure your building transfers from utility feed to generator feed during a power outage, proper switchgear maintenance is necessary. Below is an overview of the required maintenance and testing procedures for a generator system transfer switch.

Weekly inspections

A transfer switch should be inspected on a weekly basis. The inspector should check for signs of corrosion, dust accumulation, and looseness. Proper switch settings should also be checked. Weekly transfer switch inspection takes only a few minutes, but the role it plays in EPSS maintenance is critical.

Monthly testing

An emergency power system should be tested monthly with a simulated power failure test. During this test, a power transfer switch should function in the following manner:

• Signal the generator to start its engine

• Monitor the operation of the generator as it starts

• Transfer the load of a building to generator feed

• Transfer the load to utility feed when the test is complete

• Shut down the generator after its cool down period is complete

If a transfer switch fails to perform the functions above, or fails to perform them in a timely manner, a commercial power service that specializes in EPSS maintenance and repairs should be contacted immediately.

Annual maintenance

National Fire Protection Association (NFPA) codes 110 and 70B require annual switchgear maintenance that consists of the following measures:

• De-energizing the switch prior to maintenance

• Disassembling and checking the switch for signs of deterioration

• Checking the switch contacts for signs of deterioration

• Cleaning the switch

• Cleaning the cabinet that houses the switch

When cleaning the switch, care should be taken to prevent cleaning solutions from touching the inner components. When inner components are grimy, using an industrial, fast drying, no-residue electrical parts cleaner may be acceptable. But consult a commercial power service that specializes in EPSS maintenance before using one.

Annual testing

Annual testing should be performed at the completion of annual maintenance. Unlike the monthly test, which simulates a power failure by manipulating the circuits in a transfer switch, annual testing should consist of a full power failure test in which all components of an emergency power system function as if a commercial outage had occurred.

Annual infrared scanning

Infrared scanning detects abnormal heating patterns in electrical components. Often, these “hot spots” indicate serious problems in their infancy. An invaluable preventative maintenance measure, infra red scanning can also save companies money by identifying problems before they necessitate expensive repairs or replacements.

Prime Power specializes in switchgear maintenance

At Prime Power, we offer a full range of EPSS services, including:

• scheduled maintenance
• repairs
• modernization
• retrofits
• load bank testing
• breaker testing
• EPSS testing
• generator rental
• new equipment installation

If your transfer switch needs maintenance, repair, modernization, or replacement, call us today for a free consultation.

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