Installing your own generator can provide you with backup power during utility outages. While hiring an electrician is recommended for most homeowners, with proper precautions and planning, you can safely install your own generator. In this comprehensive DIY guide, I will walk you through the entire process of selecting, siting, installing, and maintaining a home backup generator system.
Choosing the Right Generator
The first step is choosing the appropriate generator for your needs. Here are the key factors to consider:
Power Output
The power output, measured in watts or kilowatts (kW), must be sufficient to operate your essential appliances and equipment during an outage. Add up the wattages of items you want to run to determine the minimum output. Be sure to account for startup wattage which is momentarily higher than running wattage.
For reference, here are the typical wattages of common items:
- Refrigerator: 500-2000 Watts
- Furnace fan: 800-1500 Watts
- LED light bulb: 5-15 Watts
- Window AC unit: 500-1500 Watts
To run your whole house, size the generator at 1.5 times your main electrical panel capacity. A 10,000W unit can cover 6-8 major appliances.
Fuel Type
Common fuel types are:
- Gasoline - Less expensive but requires refueling every 5-10 hours.
- Propane - Convenient and long-lasting but propane tanks take up space.
- Natural Gas - Hooks up to your gas supply line for unlimited run time. Requires professional installation.
For most homeowners, a gasoline or propane generator is the simplest option.
Portability
Stationary standby generators are permanently installed outside and connect to your home's electrical panel automatically when power goes out. More expensive but very convenient.
Portable generators offer flexibility in exchange for manual operation. You plug appliances directly into the generator's outlets.
Noise Level
Generators range from 65-80 decibels when running. Sound enclosures can reduce noise. Consider your proximity to neighbors.
Budget
Generator prices range from $500 for a basic portable unit up to $5,000 or more for a large whole house model. Set a budget before shopping.
Generator Siting
Proper placement of your generator is critical for safety and convenience. Follow these guidelines:
- Outdoors only - Never run a generator inside due to deadly carbon monoxide emissions.
- Away from doors, windows, and vents - Exhaust fumes must not enter your home.
- On a flat, stable surface - Prevent tipping over or sinking into the ground.
- Near your electrical panel - Minimizes cord lengths for connecting.
- Sheltered from weather - Protects the generator from damage.
- Away from flammable items - Prevents fire risk from engine heat.
- With access to fuel supply - Allows convenient refueling.
For portable generators, allow at least 5-10 feet clearance on all sides for ventilation. Construct a small ventilated shed if needed.
Electrical Connections
You must safely connect your generator to your home's electrical system to back up your household circuits.
Circuit Breaker Panel
The generator feeds power to your main breaker panel which distributes it throughout the house.
To connect it:
- Turn off the main circuit breaker.
- Connect the generator output to the input of the main breaker panel.
- Turn on the generator breaker in the panel.
- Turn on individual circuit breakers to restore power to those circuits.
Never energize the panel while connected to the utility grid - serious hazards can occur!
Backfeeding
An alternative is backfeeding circuits by plugging appliances directly into the generator.
This is only recommended for smaller portable generators on a limited number of circuits. The generator must have enough capacity for all connected loads.
Use thick, outdoor-rated 10/3 NM-B wiring cable and NEMA L14-30 plugs rated for 240V 30A.
GFCI Protection
Use ground-fault circuit interrupter (GFCI) outlets on the generator and cords for protection against shocks. Test them regularly.
Isolation Switch
For legal and safety reasons, a double-pole double-throw transfer switch should be installed to isolate the house wiring from the utility lines when running the generator. This prevents backfeed which could harm utility workers.
Hire an electrician if you are uncomfortable making these connections yourself.
Operating the Generator
Follow the manufacturer's instructions precisely when using your generator. Key steps include:
Start-up
- Check oil and fuel levels.
- Make sure appliances are turned off before starting.
- Engage the choke if the engine is cold.
- Set the circuit breakers to "off" before starting.
- Pull the starter cord vigorously until the engine starts.
Electrical Connection
- Let the generator reach stable running speed.
- Carefully plug in appliances or switch on breakers.
- Turn on appliances individually to prevent overloading.
Shut-down
- Turn off and unplug all appliances.
- Let the engine run for a cool-down period.
- Turn off the fuel valve if present.
- Switch off the breaker on the generator.
Refueling
Always shut down the generator first and let it cool before refueling. Gasoline and propane are highly flammable - exercise extreme caution.
Routine Maintenance
Your generator will provide many years of reliable service with proper maintenance. Follow the product manual, and perform tasks like:
- Changing oil and filters per the specified interval.
- Replacing spark plugs as needed.
- Checking and replacing air, gas, and carbon filters.
- Cleaning and adjusting carburetors for optimal fuel flow.
- Testing and resetting automatic transfer switches.
- Inspecting all electrical cords and connections for damage or corrosion.
- Draining old gas and sediments from the fuel tank.
Keep spare parts like oil filters, plugs, and fuses on hand for urgent repairs.
Hire a certified technician annually for a complete tune-up and safety inspection.
By selecting the appropriate generator, safely integrating it with your home's electrical system, operating it correctly, and maintaining it properly, you can successfully install a generator for backup power even without professional assistance. But never hesitate to call in an electrician if you feel unsure about any aspect of the project.
Frequently Asked Questions
How much load can I connect to a portable generator?
Consult the owner's manual but do not exceed 80% of the rated wattage for safe operation.
Where should I buy my generator?
Big box stores, hardware suppliers, and specialist dealers offer various generator models. Compare prices and features.
Does generator installation require a permit?
Permits are often needed, especially for permanent standby generators. Research your local codes.
What maintenance does a generator require?
Check oil, filters, spark plugs, and air filters regularly. Change oil based on operating hours. Clean fuel system annually.
How long will fuel last in my generator?
Gasoline generators run 5-10 hours on a tank. Propane lasts 10-20 hours per 20 lb. tank. Refueling depends on load size.
With proper planning and precautions, installing your own home backup generator is an achievable DIY project that will provide peace of mind during power outages for years to come.