What Is a Transfer Switch for Commercial Generators?
Power outages can happen anytime, putting your business at risk of downtime. Many companies avoid downtime at all costs, relying on backup power supplies like commercial generators to kick in when the main power grid fails. As a business owner or manager, you likely don’t have the time, equipment or workforce to connect each electrical device or machine to a generator when an outage occurs. A commercial generator transfer switch lets your business automatically transition from one power supply to another.
Learn more about commercial generator transfer switches and how to choose the right type for your business.
What Is a Transfer Switch?
A transfer switch is a device that transfers an electrical load between a main power source and an alternative or backup source, typically a generator. The transfer switch connects to the main breaker and generator to turn the power sources on and off during an outage to ensure your business maintains consistent power. Transfer switches also help your business comply with various electrical standards and codes, including those outlined in the National Electrical Code (NEC).
These devices can be integrated into generator applications for nearly any industry, including data centers, hospitals, telecommunication facilities and industrial plants.
How Does a Transfer Switch Work?
When a power outage occurs on a main breaker, a transfer switch proactively disconnects your power supply from the main grid and transfers the electrical load to the generator. The switch also works in the reverse order — when power is restored to the main grid, the switch transfers the electrical load from the generator back to the main grid. This operation keeps your electrical load connected to one power supply at a time, making a power transfer switch for generators a crucial piece of safety equipment.
Do You Really Need a Generator Transfer Switch?
Depending on where your business is located, local codes may require you to have a transfer switch installed with your generator. Even where transfer switches aren’t required, they are highly recommended, especially for standby generators. Without a transfer switch, your business, equipment and utility workers are at risk of damage and injury. A generator transfer switch helps prevent two scenarios — back feeding and the main power supply contacting the generator.
Back feeding occurs when the generator isn’t separated from the main grid. The generator’s power can travel back through the transformers, lines and poles on the main grid. If a utility repair worker works on the transformer or line connected to your supply, the back feed can kill them. This dangerous situation is one of the most prevalent reasons for using a generator transfer switch.
Another potential situation includes the main power supply contacting your generator. Without a transfer switch, the main power could be restored and reach your generator before it shuts off. When this happens, you’d have two power supplies feeding your business. The extra electrical surge will likely cause a fire, damaging your generator and connected equipment and putting you and your employees at risk.
Even if a transfer switch isn’t required, it’s best to use one for safety and peace of mind.
Types of Commercial Transfer Switches
Transfer switches are classified based on how they transition between power sources. Consider your electrical load when choosing between commercial transfer switches because some transitions are safer for certain loads. Here are a few transition types worth considering for your business:
- Open transition: An open transition transfer switch disconnects from a source before connecting to a new one. For example, when power is restored after an outage, an open transfer switch completely disconnects from the generator before reconnecting to the main power grid. These transitions are beneficial for loads that experience disturbances when reconnecting too quickly.
- Closed transition: Closed transition transfer switches are the opposite — they ensure a connection is made to the new source before disconnecting from the current source. In this case, the switch would connect to the restored power grid before disconnecting from the generator. With a closed transition, there’s a brief period where your load is connected to both power sources. This transition benefits loads that can’t have power supply interruptions, such as in hospitals.
- Delayed transition: These transition switches are a type of open switch, though they have a longer, intentional delay before switching power supplies. Delayed transition switches are power surge-resistant, making them ideal for loads carrying industrial equipment needing more repower time.
Manual vs. Automatic Transfer Switches
Transfer switch operations are either automatic or manual. Both switch types are beneficial for certain power needs, so it’s important to compare the two to determine which may be best for your business. As their names suggest, one requires manual operation, and the other runs automatically. So, what difference would this make for your company, and how would it affect your power supply?
Manual Transfer Switch
A manual transfer switch gets turned on and off by hand. So, when your power goes out, someone must physically turn on the transfer switch so it can transfer your electrical load to your generator. When you want to switch back to the power grid, you must manually make that switch. Manual switches are typically simple to operate, often requiring moving a lever from one position to another.
Manual switches are less expensive than automatic switches, though they’re less convenient and, in many applications, a liability. With these switches, there’s an inherent delay between transitions to power sources because you’re unlikely to have someone constantly standing next to the switch. In some applications like health care or data centers, even a brief delay in transition can create serious safety or security risks. If your business can withstand a delay until you flip the switch or operate in an area where outages are rare, you may be fine with a manual switch.
Automatic Transfer Switch
An automatic transfer switch automatically transitions between power sources. Automatic switches sense power outages and automatically signal the generator to turn on and vice versa. These more sophisticated devices come with increased convenience at a higher cost. However, the extra cost is worth it for most businesses, especially those that can’t afford downtime or security risks associated with delays between supply transitions.
Automatic transfer switches are more beneficial in many situations, especially if your business operates in an area prone to power outages.
Shop Woodstock Power for Automatic Transfer Switches
At Woodstock Power, we offer an extensive selection of automatic transfer switches suitable for various industries and applications. We’ll work with you to find the right transfer switch and generator combination to ensure your business has the backup power supply necessary to maintain operations in an outage. If you know what you’re looking for, browse our selection of automatic transfer switches. Need help finding the right fit? Contact us for expert help.