Bonding of metal piping
Bonding of metallic water lines and gas lines is required by all major codes. Being bonded is not the same as being grounded Bonding refers to the process of connecting different systems together so they have the same electrical potential as the electrical service. This is done to reduce the chance of arcing caused by a sudden surge of electricity from a nearby lightning strike or other unexpected cause.
Metallic water lines
Bonding of water lines is usually accomplished by connecting the water lines to the grounded neutral at the service panel. Connections should occur within the first 5 feet after the pipe enters the structure.
When a water meter or other device, such as dialectic unions on a water heater, breaks the continuous bond, a jumper must be installed.
Non-conductive water lines such as PVC or CPVC etc. do not need to be bonded. Water lines are no longer considered
reliable sources of grounding because of the increased use of non-conductive materials in municipal and private water lines. For specific requirements refer to the National Electrical Code Section 250.104 (A) & (B)
Metallic gas lines
Metallic gas piping is also required to be bonded in the same manner as water lines. Metal piping is considered to be continuously bonded if connected by threaded, soldered, brazed or flanged connectors. Approved flexible metal gas appliance connectors are also considered to be part of the bonding system. For specific information refer to the National Fuel Gas Code section 7.12 and the NEC section 250.104 (A) & (B)
Corrugated Stainless Steel Tubing (CSST) is a flexible gas line gaining use in place of Black Iron gas pipe. Initially limited to trained
plumbing and heating contractors, CSST is now on the shelves of most big box do-it yourself retailers. CSST must be bonded the same as the water and gas piping. For more specific information on CSST pipe refer to the National Fuel Gas Code section 7.12.2 and the NEC section 250.104 (A) & (B)
Generic Bonding Diagram
All work involving electricity should only be performed by a qualified electrician. This is intended only as a guide.
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