Millions of Americans rely on natural gas each day to make their lives easier and more comfortable.
According to the American Gas Association, an estimated 69 million homes, about half of all homes in the United States, use natural gas. Whether it’s used to heat homes or run water heaters, dry clothes, help cook food on a gas range, or do myriad other things, natural gas has become a cost-effective and reliable energy option for many Americans.
The Federal Energy Regulatory Commission (FERC) governs nearly 2.5 million miles of natural gas pipeline in the U.S., which serves about 178 million Americans through 110 LNG facilities. Although these companies safely and efficiently provide natural gas to homes and businesses all over the country, there are some rules that need to be followed to prevent unnecessary risks and protect people from dangerous situations.
One aspect of maintaining a safe gas line is to ensure the line is grounded. By grounding, also known as bonding, the gas line, there is much less risk of the tubing holding a charge and possibly causing an explosion. The process also prevents sparking by giving electricity a safe place to go and preventing build-ups or arcs that could potentially damage gas lines.
Grounding gives excess electricity a safe place to go from an appliance back to the earth. If there is a power surge during a lightning storm, or if there is a fault in the wiring system, the electricity has a place to go through the backup pathway the ground wire provides.
Homes without updated electrical installed, for example, those that rely on knob-and-tube wiring systems or have a plethora of two-prong outlets, may not have a ground wire. Without a ground wire, these systems come with a higher risk of shock hazards. They may also short-circuit electronics and appliances during a surge.
The same goes for gas lines that are not grounded. Without grounding, there is a chance the tubing could become damaged by a spark, arc, or other electrical discharge. If the tubing is damaged, a leak could form. Even worse, there could be a fire or explosion.
The first thing to do when deciding to ground a gas line is to determine if it needs to occur. In many cases, gas lines are grounded if they are connected to an appliance like a gas range, water heater, or furnace.
However, this is not always the case. When corrugated stainless steel tubing (CSST) has been installed, grounding wire must be used. The tubing was first made available in the U.S. in 1990 and has plenty of benefits that make it an attractive product for installers. CSST is flexible, making it better across long runs, and offers good damage protection during an earthquake.
Older CSST lines, which are yellow, require bonding with a grounding wire because they are more likely to become damaged, leading to possible damage, fire, or an explosion. Newer lines, which are black, may not require the same grounding. Unfortunately, even if most of the line does not include CSST, the line needs to be bonded using bare or insulated grounding wire.
According to the National Fuel Gas Code (NFGC) Section 7.12.2, CSST lines “shall be electrically continuous and bonded to the electrical service grounding electrode system or where provided, lightning protection grounding electrode system.”
As mentioned previously, grounding may not always be required, especially if the appliances those lines are connected to are grounded already. In Section 7.12.1, the NFGC states, “Gas piping other than CSST shall be considered to be bonded when it is connected to appliances that are connected to the appliance grounding conductor of the circuit supplying that appliance.” In layman’s terms, if the gas utilizing equipment the line is connected to is properly grounded, the line itself is compliant and does not need bonding.
Other organizations maintain similar rules for bonding gas lines, including the National Electrical Code. The NEC states in Section 250.104, “any metal piping likely to become energized must be bonded to a grounding electrode system.” A grounding electrode is a conductive material, like a metal ground rod, water pipe, or steel bar, with a bonding conductor (wire) attached to it. These systems let electrical currents from a fault in the wire flow safely to the ground without causing damage.
Other rules require what size the grounding wire needs to be. In Section 310.1.1 of the NFGC, the bonding jumper must be more than 6 AWG and be a copper wire or equivalent. This sizing prevents the grounding wire from overloading, causing damage to the ground wire or the line it is protecting.
When grounding a gas line, installers can use either a bare copper or insulated copper wire if it meets the size requirements laid out by the NFGC. Other options, including tinned copper, which is copper coated with tin, may also be a suitable grounding wire solution for wet environments and high-temperature situations.
Bare copper is a less expensive option that works well in areas where conductivity and flexibility are vital. Insulated copper is better suited for pulling through conduit, thanks to its PVC or HMWPE insulation, and is better at absorbing abrasion damage than a bare wire. Tinned copper is more corrosion resistant than bare copper and has a longer lifespan.
All three of these wire types accomplish the same goal of grounding equipment and lines. With that said, always consult local codes to see what specifications may be required.
Home and building owners may not always know what is best for them. It’s up to the installer, inspectors, and code enforcers to understand and recognize when gas lines could be non-compliant.
If those lines are not properly grounded, they risk becoming charged, leading to potentially terrible outcomes, including death. By bonding the lines with a copper wire, it is possible to reduce the risk of an electrical arc or spark causing damage and keep people safe.