Water Heater Bonding Wire Size

The bonding jumper is to be sized using table 250 66.

Water heater bonding wire size.

4 copper wire is sufficient for service not exceeding 200 amps. 1 in. Each bonding jumper must be sized in accordance with table 250 66. This is from a different table of sizes for grounding electrode conductors as opposed to ground wires from main panel to subpanel grounding conductors.

A bonding wire is an external part that is attached to the water heater. The system amperage usually 100 or 200 amps determines the required gauge of the bonding wire you need. Wire a hot water heater with wire that s sized to accommodate the heater s current requirement. It should be noted that the national electric code does not require a bonding wire on a water heater.

Smaller less expensive copper wire is allowed for services between 100 and 175 amps. 10 sol str 2str. An acquaintance has an older mobile galvanized branch water lines and his water heater. For gas piping you can bond it to the same things as mentioned for water piping.

Next time you install an electrical system be sure to check both the hot and cold water lines to ensure proper bonding of the water piping system to the service. For example a 20 amp hot water heater needs 12 gauge wire a 25 amp hot water heater requires 10 gauge wire and a 30 to 40 amp hot water heater requires 8 gauge wire. For 200 amp service use a 4 gauge copper wire from the panel to the water pipe within 5 feet of where it enters the house and also between where it enters and the meter. 40 gal 240v dual 4500w 18 75a connected to the circuit breaker panel double pole 40a breaker with a 12 20amp cable.

For 200 ampere service you ll probably be using 4 awg copper or 2 awg aluminum. Some large heaters draw up to 50 amps requiring 6 gauge wire. Again both the hot and the cold water pipe must be bonded to the separately derived system. The southwire water heater grounding kit is designed for residential water heater use but can be used across any continuity break in residential plumbing.

One clamp is placed on the cold water pipe while the other goes on the hot water pipe. Kit includes two brass ground clamps and copper conductor. This bonding is essential to maintain continuous ground path.