Natural Gas Lines for Standby Generators in Spartanburg, SC

Every generator lists its gas consumption at full load in the installation manual, in cubic feet per hour or BTUs per hour, and lists a separate figure for natural gas and for propane. For a whole-house air-cooled unit that full-load number can rival or exceed everything else in the house combined. We size from the manual for your specific model, not from a rule of thumb.

Sizing has to assume the worst case, because that is when a generator runs. On a cold January night with the power out, the generator is at or near full load and the gas furnace, the water heater and maybe the gas logs are all running too. The line from the meter has to carry the total, and the pipe size depends on that total and on the length of the run, under the tables in the fuel gas code.

Generators also have an inlet pressure range they need to see while running, listed in the manual. We check it with a manometer at the unit, at idle and under load, before the job is done. A pressure that looks fine at rest and drops when the engine loads up is a sizing problem.

Your meter and regulator are sized by the utility for the load they expected when service was set. Add a large generator and the total can exceed what the meter is rated to pass. That is not something a contractor can change; the meter belongs to the utility.

So early in the planning we add up the connected load and tell you whether the utility needs to review the meter. In much of Spartanburg County that is Piedmont Natural Gas, and around Duncan, Lyman and Wellford it is Greer CPW. The utility's own schedule governs any meter change, which is why we raise it at the start rather than on install day.

On propane, the same question applies to the tank and regulators. A tank sized for a furnace and a water heater may not vaporize enough gas to run a large generator in cold weather, and its run time on a full tank may be shorter than you expect. Your propane supplier sizes and sets the tank and its regulators; we run the line from there.

Most generators sit on a pad beside the house, and the gas usually reaches them underground. We run polyethylene pipe below grade with a tracer wire, transition to steel through a riser at the pad, and put a manual shutoff valve there where it can be reached without opening the enclosure.

A generator vibrates when it runs, and a rigid pipe connection would carry that vibration into the riser and threads. Manufacturers specify a flexible connector between the supply piping and the unit's gas inlet, often shipped with the generator, and list where it goes and how it attaches. We follow that, along with any sediment trap the manual calls for at the inlet.

Placement matters too. Manufacturers list clearances from windows, doors, vents and the house wall to keep exhaust out of the home. The generator's location is usually settled with the electrician and the homeowner before the gas line is planned.

A generator install is two trades. The electrician handles the pad, the unit, the transfer switch and the wiring to your panel, under the electrical permit. We handle the gas: sizing, piping, testing and connecting the fuel supply. The work goes smoothest when both are planned together.

We set the riser where the electrician will set the unit, schedule the gas test and inspection so the line is ready when the generator is, and are there when it is first started to confirm the gas pressure under load. If you are hiring the electrician yourself, give them our number and we will coordinate directly.

Some portable generators are built to run on natural gas as well as gasoline or propane. For those, we can run a gas line to an outdoor spot well away from doors, windows and vents, and end it in a shutoff valve and a listed quick-connect coupling, so the generator can be hooked up during an outage without anyone touching the house piping.

The same sizing rules apply on a smaller scale: the line has to carry the generator's rated gas draw along with the furnace and water heater. The generator itself still needs a transfer switch or an inlet installed by an electrician, and it must always run outdoors.