Buying Guide

Best Transfer Switches for Your Generator

Types of Transfer Switches

Permanently hard-wired to and installed near the electrical panel in your home, transfer switches solve the problem of backfeeding, which occurs when electricity runs backward out of the house and through the utility transformer. 

There are two types of transfer switches: manual and automatic transfer switches. This refers to the way in which the switch is turned on and off during use. 
Per the National Electrical Code (NEC), all transfer switches must have a three-position “LINE-OFF-GENERATOR” or “ON-OFF-ON” switch to keep power from accidentally backfeeding. 
The three-position switch ensures that the switch goes through the off position when traveling from the generator position to the line position, fully disconnecting the generator every time before the main utility switch is turned on. 

Tip: Many areas require a transfer switch to be installed by a licensed electrician. Be sure to check local electrical codes before installing one yourself. 

Manual vs. Automatic Transfer Switches
transfer switches
transfer switches
Description Manual transfer switches Automatic transfer switches
Feature/Benefits These switches are hardwired to your control panel and used to power portable or optional standby generators. They must be manually turned on and off when the electricity goes out or comes back on. This may be problematic if you aren’t home during a power outage. In addition, they are wired to essential circuits in your home, such as lights and furnace blowers that can’t be run with an extension cord. These switches automatically turn the generator on and switch power to it when they detect a drop in line voltage. Then they turn the generator off when they sense the line power is restored. They can be used with portable generators as long as the generator has an electric starter. They are most often used with automatic standby generators, the permanently installed generators that look like central air conditioner units.
Additional Options

Your transfer switches can be pre-wired or attached to an inlet box

Pre-wired transfer switches come with all of the wiring you need to connect the switch to the main breaker panel. All you need to do is attach the conduit to the main box, pull the wires through the conduit, and wire the circuits on the transfer switch to the breakers on the main panel representing the circuits you want to power with the generator. 

An inlet box, mounted to an outside wall and hard-wired to a cord-connected transfer switch, keeps you from having to run the heavy-duty generator extension cord into the house to power the generator. 

Outdoor transfer switches must be encased in weatherproof housing. They are installed on an outside wall as close to the main breaker panel as possible.

Know the difference between an automatic and manual transfer switch to determine which best suits your home's electrical wiring system. Learning how to choose a transfer switch for your generator will ensure the best performance in case of a power outage. You may need a qualified electrician to install it.