Duke Energy Excess Flow Valve (EFV) Program

Excess Flow Valves

Natural gas is a safe and reliable fuel when used properly. However, outside forces (weather, natural disasters, excavation damage) can cause a break in the natural gas service line. An excess flow valve is a device that automatically closes and restricts the flow of natural gas if that flow exceeds prescribed limits, such as when the service line is damaged due to excavation or other similar activities. 

An excess flow valve is designed to permit normal operation of the service line. But, when activated, an excess flow valve may lessen the buildup of natural gas in the service line and may decrease the possibility of accidents caused by such buildup. However, an excess flow valve does not protect against customer appliance malfunction, customer houseline leaks, or small leaks on service lines or gas meters.

Current federal regulation requires Duke Energy to install an excess flow valve on qualifying natural gas service lines for single and multifamily residences and small commercial properties. Where an excess flow valve is not required on service lines installed before the current regulations, customers have the option to install the device at their expense. Operating characteristics and limitations may prevent the installation of an excess flow valve. 

Excess flow valves are designed for use on the gas service line, downstream of the gas main. 
Excess flow valve graphic

EFV Installation Guidelines

Installation of an excess flow valve requires Call Before You Dig notification (811), utility marking, and significant soil excavation on or near customer property where the existing natural gas service line connects to our natural gas main. Natural gas service to the customer’s home or business will be interrupted for a period of time and the customer must be present for natural gas service to be restored upon completion of the excess flow valve installation. The natural gas service line will need to be inspected and all appliances must be operating normally before the customer’s gas service can be restored.

The cost to install an excess flow valve will be the sole responsibility of the customer requesting the installation. The cost to install the excess flow valve varies, depending on the difficulty of the installation, but the average cost of installation is $1,500. Once a customer requests an excess flow valve, Duke Energy will send a representative to the property to confirm that the excess flow valve can be installed and to prepare a cost estimate. The customer will be responsible for the actual cost of installation.

Upon acceptance of the cost estimate and prior to installation, customers will be required to enter into an agreement with Duke Energy. The agreement will contain the terms and conditions of installation including the customer’s obligation to pay for all of the actual EFV installation costs. Installation work will be scheduled at a mutually agreeable date, subject to approval from regulators and permitting authorities, payment arrangements, and weather conditions.

Contact Us

To find out if your property currently has an excess flow valve or to learn more about having one installed at your expense, please call 888.385.3638 or you can email the excess flow valve project team at EFV@Duke-Energy.com to get information about the process. You can also find additional details about the project by visiting www.Duke-Energy.com/EFV.

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Frequently Asked Questions

Excessive Flow Valves

  • An excess flow valve is designed to permit normal operation of a natural gas service line, but will automatically restrict natural gas flow when the flow exceeds prescribed limits, such as when the service line is severed due to excavation and similar activities. When a higher flow rate than the maximum allowed is detected, an excess flow valve immediately snaps shut to restrict the supply of natural gas.
  • An excess flow valve operates similar to electrical circuit breakers that trip when the electricity current exceeds its limit. The excess flow valve is tripped by an excess flow of gas, causing the spring to restrict the flow. The valve is reopened when the excess flow has ceased or the correct pressure is regained.
  • No. An excess flow valve does not protect against small leaks on the service line or gas meter or leaks beyond the meter assembly, such as those involving a customer’s house piping or customer appliance malfunction. It is designed to activate when the service line is damaged due to excavation or other similar activities.
  • An excess flow valve is designed to allow normal operation of the service line. It will automatically restrict the flow of natural gas only when the service line has been severed and the flow of natural gas exceeds prescribed limits.
  • If you smell natural gas inside your home, leave immediately and call 911 and Duke Energy at 800.634.4300 from a safe location.
  • Duke Energy is required by federal regulation to install an excess flow valve in all qualifying new or renewed natural gas service lines that serve single and multifamily residences and small commercial properties. If the installation is not required by federal regulation, customers have the option of requesting an excess flow valve.
  • Duke Energy or one of its licensed contract crews must install the excess flow valve.
  • In those circumstances where installation is not required by federal regulation, it is the customer’s option to install the device at his or her expense.
  • The cost to install an excess flow valve varies, depending on the difficulty of the installation. But the typical cost of installation is $1,500. Duke Energy will work with each customer, on an individual basis, to discuss installation and cost.
  • If it is determined that the excess flow valve can be installed, Duke Energy will provide a cost estimate and discuss arrangements for installation. An agreement and 50 percent deposit will be required before work begins to install the excess flow valve. Duke Energy will work with customers on an individual basis regarding payment of the balance owed.
  • No. The cost to install the excess flow valve must be billed separately and cannot be included on your normal monthly Duke Energy bill.
  • The excess flow valve is installed on the service natural gas line that runs underground between the gas main (usually located in or near the street, alley or easement) and the gas meter on the customer’s property. Installation of an excess flow valve requires digging so that the service line is exposed prior to installation. All areas excavated will be restored once the installation is complete.
  • No. Only Duke Energy or its approved contractor can do the installation.
  • Duke Energy will send out a representative to your home to determine if an excess flow valve can be installed at your home. Due to operating characteristics and limitations, in some instances, an excess flow valve cannot be installed. Each customer location will be evaluated upon request.
  • The device is designed to last the lifetime of the natural gas line. However, if your natural gas service line is replaced in connection with overall system maintenance activities, the excess flow valve will also be replaced. The costs of this replacement would be included in overall maintenance costs.
  • Federal regulations did not require excess flow valves to be installed on newly constructed residential homes until February 2010. To verify whether an excess flow valve has been installed at your property, call Duke Energy at.888.385.3638 and a company representative will contact you regarding this issue.
  • No. Once installed, the excess flow valve becomes part of Duke Energy’s natural gas distribution system and it cannot be removed.
  • No. Installing an excess flow valve will neither increase nor decrease a customer’s natural gas usage.
  • To speak to a member of our Duke Energy EFV installation team, please call 888.385.3638 or you can email the team at EFV@Duke-Energy.com to get additional information about the process. You can also find additional details about the process by visiting www.Duke-Energy.com/EFV.
  • You may request to have an excess flow valve installed at your expense at any time.
  • Installation of an excess flow valve requires digging so that the service line is exposed prior to installation. Duke Energy or its contractor will restore property to its original condition as part of the overall project cost.
  • Yes, installation of the excess flow valve will require us to temporarily shut off the gas supply to your property. As part of the installation process, your existing houseline piping must be retested and appliance pilots will be re-lit if your houseline piping and appliances are operating normally. If the houseline test fails or appliances do not pass inspection, you will be responsible for repairs before natural gas service can be fully restored.
  • Installation of the excess flow valve will be completed on a mutually convenient time and after all necessary permits and regulatory approvals are obtained. The length of time to install will vary based on the complexity of the installation.
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