# Water heater bonding



## Stubbie (Jan 7, 2007)

mikem201 said:


> when grounding a hot water heater is it best to ground both the hot outlet and cold inlet? Also, what gauge copper wire is best to use?


Are you talking about this which is bonding not grounding


----------



## Jim Port (Sep 21, 2007)

What size is the service?


----------



## AllanJ (Nov 24, 2007)

Bonding at the water heater consists of the following:

1. A bonding jumper, pictured above, between the water heater inlet and outlet. It would be #6 copper for electric services up to 100 amps, #4 for services of 100 to 150 amps, I don't have the table handy for larger services. If either or both of these are plastic then the bonding jumper(s) go from each metal section of the hot water plumbing downstream (upstairs, etc.) to grounding electrode conductors or bonded metal cold water pipe.

2. One of:

2a. For water heaters that use electricity, the properly connected equipment grounding conductor in the electrical feed.

2b. For gas water heaters that don't use electricity, a bonding jumper from the gas piping (anywhere along it) to a grounding electrode conductor or grounding electrode.

Plumbing may not be part of the equipment grounding path from an electrical load (light, appliance, receptacle, etc.) to the panel. One of the reasons is that the chance exists that at a later date a section of plastic pipe may be substituted for metal pipe and installation of a bonding jumper across the plastic section neglected.


----------



## mikem201 (Jan 9, 2009)

Jim Port said:


> What size is the service?


service is 100amps. What is difference between bonding and grounding? FYI my hot water heater is gas.


----------



## AllanJ (Nov 24, 2007)

Bonding -- Interconnecting two metal items using an essentially resistance free electrical connection. If A is bonded to B and B is bonded to C then A is bonded to C. Electrical codes include additional rules that imply how many amperes must be able pass over the interconnection. For example an adequate bond might be a #20 gauge wire between a component and the chassis inside a TV set but might need to be a #4 gauge wire between an electrical panel and a water pipe.

Grounding -- (1) Connecting (bonding) to a properly installed ground base (grounding electrical system) of an electrical system. The GES consists of the ground rods, main water pipe if metal exiting the house underground, neutral/ground bus bar in the panel with the first main disconnect, and fat (typically #6 copper) wires (grounding electrode conductors) connecting these items. (2) Providing contact with the ground (earth, soil) using means such as ground rods or the reinforcing bar inside a buried concrete slab, sometimes metal plates.


----------



## electures (Dec 22, 2009)

mikem201 said:


> service is 100amps. What is difference between bonding and grounding? FYI my hot water heater is gas.


Bonding eliminates any difference of potential. Grounding means connected to the grounded service conductor and grounding electrode system in the building.


----------

