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From the Field
Running a Gas Line to a Standby Generator
What the gas side of a standby generator involves, who handles each part, and what to ask before you buy.
Quick answer
Short answer: A standby generator that runs on propane or natural gas needs a gas line sized for the generator and the rest of your gas appliances. A licensed plumber runs and tests the gas line, an electrician wires the generator, and your county or city usually wants permits.
- Who this is for: homeowners planning a standby generator on propane or natural gas.
- What Ryan does: gas line installation, propane and natural gas. The generator itself is set by its installer or an electrician.
- What decides pipe size: the generator's fuel use, the length of the run, and the other gas appliances on the line.
- When to start: before you buy, so the fuel and the permit plan are settled.
Many people search for a unit by its size, such as a 16 kW Generac, and then wonder what the gas side takes. The generator is only half of the job. Fuel has to reach it in a safe, steady way, and that is plumbing work. This page covers the gas line only, in general terms.
Ready to talk through the gas side?
Text Ryan the generator model and where the gas meter or tank sits. He answers his own phone.
Who Does What
- Generator installer or dealer: sets the unit, handles the pad and the manufacturer's rules.
- Electrician: wires the generator and the transfer switch, the device that keeps your house power from feeding back into the grid. Generac's own guidance calls this work for professionals.
- Licensed plumber: runs the gas line to the generator, with the right pressure regulator, then purges and tests it. Ryan is a licensed Master Plumber and does gas line installation.
- Building department: usually issues permits for the electrical and gas work.
Ryan does not set or wire the generator. If you already have an installer, he can work on the gas line alongside them. Call or text him to talk through your plan.
Propane or Natural Gas?
Natural gas comes from a utility line in the street. In the mountains around Ellijay, Blue Ridge and Blairsville, many homes sit past the end of the gas main, so propane in a tank is common. Check with your gas utility to find out if natural gas reaches your address.
- Natural gas: no tank to refill, but the line from the meter must carry the generator's load plus your furnace, range and heater.
- Propane: stored in a tank on your property that a supplier fills. The tank size matters for how long the generator can run in an outage. Your supplier can help you size it.
- Both: the piping and regulators must match the fuel. The two are not interchangeable.
If you already have a propane water heater or range, the new generator shares the same fuel supply. See our guide on gas, electric and propane water heaters.
How the Gas Line Gets Sized
Gas pipe size depends on three things: how much fuel the generator burns at full load, how far the pipe runs from the meter or tank, and what else is on the same line. The generator's manual lists its fuel use. Do not guess the pipe size from the kW number alone.
A generator that pulls from a line that is too small can starve under load. That is why installers and building departments want sizing calculations in the permit plan. Generac's support page says piping should follow NFPA 54 for natural gas, and NFPA 58 or the ICC fuel gas code for propane, and that pressure should be checked so it does not drop once the generator runs.
Permits and Testing
Permit rules differ by county and city. Call your local building department before work starts, since some places need an electrical permit and a separate gas permit. Your homeowners association may have rules on where the unit can go.
After the pipe is in, the line should be purged and leak tested. Generac says to purge and leak test the fuel line and verify pressure. If anyone ever smells gas near the unit or the line, leave first and call from outside. See what to do if you smell gas.
Generator Safety You Should Know
The CDC says never to use a generator inside your home or garage, even with doors and windows open. CPSC says portable units go outside only, at least 20 feet from the home, with the exhaust pointing away. A standby unit is built for permanent outdoor use, but the same carbon monoxide risk is the reason clearances matter. Our page on carbon monoxide and gas appliances covers alarms.
Why Mountain Homes Plan Ahead
A power outage on a well means no water, because the pump is electric. Our post on well water during a power outage explains what to do. A generator that covers the well pump, the heater and the furnace keeps a house livable in a winter outage. Plan which loads you want to cover, and tell your installer.
What to Have Ready When You Call
- The generator model, or the one you plan to buy.
- Whether you use propane or natural gas, and where the meter or tank is.
- A rough idea of where the generator will sit compared to the meter or tank.
- A photo of the existing gas meter or tank and any gas appliances.
Ryan gives a free estimate, so you know the price of the gas line work before it starts. Work is backed by a warranty, with terms given in writing at the estimate. See the gas line installation page.
Common Questions
Does Ryan install the generator?
No. Ryan runs the gas line, propane or natural gas. The generator itself is set by its installer or an electrician.
Can I run propane or natural gas to a generator?
Yes. Units are made for one or the other, and some can switch with a kit from the maker. Check the manual, and use the right pipe and regulator for the fuel.
How do I size the gas line?
It depends on the generator's fuel use, the length of the run and the other appliances on the line. The manual lists fuel use. A plumber does the sizing.
Do I need a permit?
Often yes, for the gas and the electrical work. Call your county or city building department first.
Can a generator run my well pump?
It can if the unit and transfer switch are sized for the pump. Your electrician and installer decide that.
Is it safe to run a generator in the garage?
No. The CDC says never to run a generator in your home or garage, even with doors open.
Related Reading
Planning a gas line for a generator?
Call or text Ryan. He gives a free estimate, so you know the price before any work starts.