Ultimate Transfer Switch Buying Guide

Customers often ask if any generator can be purchased and used without a transfer switch. The answer depends on the type of generator being used. 

For instance, a standby generator cannot be used without a generator transfer switch; it would be similar to installing an air conditioning system without a thermostat—the system would not function. On the other hand, portable generators do not necessarily require a transfer switch to operate, though using one is more convenient and safer than running multiple extension cords. 

Many times, customers will ask, “What is a generator transfer switch?” or "Which transfer switch is required for a specific generator?" 

In short, a generator transfer switch acts as the "brains" of the system, connecting the generator to the home for direct power. This guide explains how this process works for both portable and standby generators and provides a wealth of additional information. 

Connecting Portable Generators 

There are three primary components used to hook up a portable generator to a home's main breaker: a manual transfer switch, a power cord, and, in many cases, a power inlet box. 

The amperage of a manual transfer switch should match that of the largest outlet on the portable generator. The power cord and power inlet box must also be matched to this amperage, which is why it is recommended to purchase all components at once. 

Manual Transfer Switch 

A manual transfer switch allows select home circuits to be powered by a single cord running from a portable generator to the main breaker panel, though a power inlet box is sometimes necessary. 

In practice, this means any circuits wired to the manual transfer switch can be used during an outage, but these circuits must be determined at the time of installation. 

Without a manual transfer switch, multiple extension cords would have to be run from the generator to various indoor appliances. Furthermore, systems such as a furnace or central air conditioner cannot be backed up without a transfer switch because they are hardwired to the breaker panel. 

For those who experience regular power outages, it is highly recommended to have an electrician install a manual generator transfer switch for easier power access and convenience. 

Power Cord 

A power cord is required to connect the manual transfer switch to the portable generator. 

It is essential that the amperage of the power cord matches the largest generator outlet. If the cord does not match, the generator's full potential cannot be utilized. 

Power Inlet Box 

If an indoor manual transfer switch is used, a method to connect the power cord is required. 

This is the purpose of a generator power inlet box. It is mounted on the exterior of the house and is hardwired to the manual transfer switch inside. During a blackout, the generator is simply plugged into the inlet box via a power cord. 

An outdoor transfer switch has the power inlet located on the bottom of the unit since it is installed outside; in this case, a separate power inlet box is not necessary. 

Transfer Panels 

For greater flexibility regarding which items can be powered by a portable generator, a generator transfer panel may be considered. 

Unlike a manual transfer switch, which is permanently hardwired to select circuits, a generator switch panel can power different circuits at different times because it is connected to the entire breaker panel. Therefore, if a user wants to power the kitchen and living room during the day but switch to the bedrooms at night, the adjustment is easily made. 

Just as with an indoor transfer switch, a power inlet box is required to connect the generator to a transfer panel. 

Connecting Standby Generators 

When a home standby generator is purchased, a transfer switch is required without exception. 

Automatic Transfer Switch 

Standby generators do not work with manual transfer switches. They require an automatic transfer switch, which links the generator to the home. 

An automatic transfer switch constantly monitors the utility power coming into the home. When a blackout occurs, it automatically switches the home to standby power without any manual effort. 

Expert Assistance 

Transfer switches are not the easiest pieces of equipment to understand, but they are extremely important to the operation of a generator. With this information, the function of transfer switches should be clearer. If questions remain, experts are available to discuss which transfer switch is required for a specific application.