Generator Power Inlet Box Buying Guide

A generator inlet box, also known as a power inlet box, functions like an electrical outlet for a house. It allows a portable generator to be connected to a manual transfer switch in a basement quickly and easily. 

What is a Generator Inlet Box? 

A power inlet box is used when a portable generator must be connected to a manual transfer switch located in a basement. Although power cords can be run through a basement window, this is not always ideal, depending on the location of the window. Instead, an electrician can install a generator inlet box on the side of a house and hardwire it to the transfer switch. It is important to remember that a generator must remain outside and away from windows to avoid carbon monoxide from leaking into a home. 

Put another way, when connecting a manual transfer switch to a portable generator, the generator inlet box serves as the link, or gateway, that allows power to flow into essential circuits to power the house. The diagram below visually depicts where a power inlet box falls in a typical manual transfer switch basement application. 

Installing a Generator Power Inlet Box 

An electrician installs the power inlet box on the side of the house near the main electrical panel. Inside, it is hardwired to a manual transfer switch, which restores power to the main electrical panel. 

When the power goes out, one end of a power cord is simply connected to the portable generator outlet. The other end is plugged into the power inlet box. The process is as simple as plugging in outdoor holiday lights. 

When to Install a Power Inlet Box 

Before an electrician begins drilling a hole in the side of a house, it should be confirmed that a power inlet box is truly necessary. 

If the main electrical panel is installed in a garage, an inlet box is not required. A power cord of at least 25 feet and a manual transfer switch with an outlet are sufficient. In this setup, the generator connects directly to the transfer switch through the garage. It is vital to ensure the generator is far enough away from the house to avoid the inhalation of any fumes. 

The same applies to a basement. If a nearby window is available and convenient, the power cord can be dropped through the window and connected directly to the transfer switch. 

If the decision is made to install a power inlet box, there are a couple of options to consider. First, the inlet box amperage must match that of the power cord and transfer switch. Second, selecting a paintable model allows it to blend in with the exterior of the house. 

Connect Your Power 

A generator inlet box serves as a convenient connection point when a power cord cannot be run directly to the transfer switch.