While extension cords might do the trick, there’s a better and safer way to run a generator when the power is out—transfer switches. Master electrician Heath Eastman helps a homeowner install a set in his home.
There’s nothing quite as handy as a backup generator when the power goes out. These devices can keep the house warm, keep the lights on, and ensure everyone stays safe. But they’re not quite as safe as they can be if they’re hooked up to extension cords and running inside an attached garage. There are better options, and master electrician Heath Eastman helps a homeowner set theirs up correctly.
First Things First: Move the Generator Away from the Home
The first thing a homeowner must do to run a generator safely is to move it away from the home. Running a generator inside a garage or even close to a window can allow exhaust fumes containing carbon monoxide into the home, creating very dangerous conditions.
Instead, the generator should be moved outside to a level, stable surface at least 10 feet from the home. Also, position the generator so that the exhaust is pointing away from the home to prevent the fumes from drifting back in.
Hooking Up a Generator to the Home
A power inlet box is necessary to hook the generator up to the home. These devices are installed on the home’s exterior and feature a port that the homeowner can use to connect the generator to the home. These devices are weather-resistant, but power inlet boxes with bottom-mount inlets are the safest to use.
Power cords are necessary to connect to these inlet boxes, but these cords are far beyond typical extension cords. They generally feature a twist-lock design, which means the homeowner inserts the prongs into the outlet and twists, locking the cord into the outlet to prevent it from pulling out.
Connecting to the Panel: Transfer Switch vs. Mechanical Interlock
For a generator to be used safely, it should be connected to the home’s breaker panel. This way, it can feed electricity through the home’s wiring rather than extension cords lying across the floor and running from room to room.
There are two ways to hook up a generator to the home’s electrical system: transfer switches or a mechanical interlock. These devices prevent the home from receiving both utility power and generator power at the same time.
A transfer switch is installed between the electrical panel and the power inlet, and it allows the user to power up certain circuits such as heating, refrigeration, and outlets or lighting throughout the home. However, it cannot power the entire home unless the generator is designed to do so.
A mechanical interlock installs in the electrical panel and connects the generator to the electrical panel. This device has mechanical bars that prevent the main breakers and generator breakers from being in the “On” or live position at the same time. However, the user will have to manually monitor and select the circuits that are active to prevent overloading the generator.
For simplicity’s sake, transfer switches are typically the easiest to use.
Generator Hook-Up Procedure
A licensed electrician should perform a generator hook-up installation, but here are the general steps involved in the installation.
- Call the local utility company to shut off the power to the panel. They’ll pull the meter and then test it to ensure there is no power feeding the panel from the utility company.
- Choose a location for the transfer switch and install a mounting board. Typically, this will be a plywood board attached to the frame in close proximity to the electrical panel.
- Run flexible conduit from the transfer switch to the electrical panel and connect the individual circuits. Each set of two wires is labeled, and one will run to the breaker while the other is connected to the wire that came off the breaker.
- Choose a location for the power inlet box. Be sure to check outside to ensure that it won’t interfere with deck stairs or other outside items. Run conduit through the home to the inlet box, and wire the inlet plug to the transfer switch box.
- Test the generator and the transfer switches before calling the utility company to replace the meter.
For the generator hookup, the homeowner chooses to have Heath install a transfer switch.
Heath mounts a piece of plywood to the wall studs to provide a secure and safe area for
the transfer switch to be installed.
Heath uses a hole saw to cut through the shelves to run the conduit from the transfer
switch to the exterior receptacle.
All materials used can be found at most home centers.