How Does an Automatic Transfer Switch Work?

An automatic transfer switch (ATS) connects a facility’s electrical power to a backup generator. Under normal circumstances, electricity flows from the utility to a building’s main electrical panel that powers all circuits. Essentially, the ATS acts as the “brain” of the entire electrical system, monitoring power levels 24 hours a day, seven days a week. If it detects that power has dipped below preset limits—in a blackout, for example—it automatically switches the building to generator power. When the ATS detects that power has been restored, it switches the facility to utility power.

No place an ATS can’t help

Any facility or operation that requires standby electrical power can use and benefit from an ATS. Although ATSs are primarily found in permanent buildings, they also support temporary facilities, like construction sites and military bases.

Although a solution to a handful of essential facilities, the most likely place to find an ATS is in any facility with life safety requirements. For example, high-rise buildings, hospitals, convention centers, schools, and hotels are all facilities where large numbers of people are likely to assemble. The National Fire Protection Association (NFPA) 101 Life Safety Code spells out the electrical safety requirements for the design and maintenance of such locations. In addition, the code includes electrical requirements that ensure the safety of all people in emergency situations.

Imagine the power goes out in a large hospital. NFPA 101 dictates that life-safety loads must be restored within just 10 seconds, including emergency lighting, alarm systems, ventilation, smoke control, fire pumps, and life-saving medical equipment .In other words, automatic transfer switches are instrumental in ensuring continued safety in emergencies.

Must-have maintenance

Automatic transfer switches require a special level of care, as a well maintained and tested ATS ensures reliable and dependable power to mission-critical systems. Not everyone is equipped to handle ATS maintenance.

When maintaining, testing, or troubleshooting an ATS, a properly trained and licensed electrical technician will look for worn, loose, or broken components. Insulation and wiring can experience deterioration from abrasions, wears, and cuts. Finally, they will seek any burning odors, melted pieces, or oxidized metals caused by overheating.

Automatic transfer switches are often found in industrial settings. Unfortunately, this means environmental contaminants—like moisture, dirt and dust—are likely to accumulate. A knowledgeable technician will know to avoid cleaning at ATS with a blower or compressed air as they can cause contaminants to become lodged in the equipment. Instead, the technicians will use a vacuum, cloth, or brush. The tech will then lubricate the transfer solenoid mechanism, tighten the control wires and check the primary contacts with an infrared camera.

An ATS continuously monitors utility power, and ATS deployment criteria should be carefully calibrated. If the utility voltage falls below the level predetermined by a facility, the ATS will decide the power source is unacceptable and initiate the transfer to generator power. Alternatively, the pickup voltage identifies when the power source is acceptable again. Both voltages are set depending on the given needs of a facility. A technician will carefully calibrate the dropout and pickup voltages to ensure proper operation.

Trust the experts

Automatic transfer switches are critical pieces of any facility’s emergency power system. If these complicated yet potentially life-saving. Transfer Switches aren’t handled correctly, they can be dangerous pieces of electrical equipment. Installing, maintaining, or troubleshooting an ATS requires specialized training and licensing.

The unfortunate reality is this: we live in a litigious society. When the power goes out, it’s the facility owner that’s on the hook if someone gets hurt. By using technicians properly licensed and trained technicians for the ins and outs of automatic transfer switches, you avoid potentially devastating legal consequences.

EPC Electric adheres to the strictest safety protocols, ensuring the well-being of our technicians, our client’s personnel and property, and the general public. We service all brands and types of emergency power systems, and our work adheres to the strict guidelines of the National Fire Protection Association (NFPA).

Get in touch with us today to learn more.

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