Our inspectors are going to enforce new rules about grounding and bonding. It strikes me as wrong because we are moving back 40 years to when I started in this trade. The problem only applies to buildings with a metal water supply and metal internal piping – most buildings that might need a service upgrade.
40 years ago, (when I started) the neutral was grounded to the nearest cold water line and the meter was jumpered to maintain the ground if the water meter was removed. City employees were reportedly getting shocks when they changed water meters.
When plastic water lines became popular so a plumber might replace a section of copper line with plastic, we grounded to the street side of the water meter and bonded the inside copper lines.
Now, we are to ground the neutral at the top of the mast. The ground wire runs to the meter socket where the socket is bonded, and continues to ground rods or a ground plate. My understanding of this type of ground is that it will have a resistance of more than 10 ohms, and a lot higher when the ground is frozen.
From the meter socket, the panel is bonded. The closest cold water line is bonded to the panel. So, the neutral is electrically connected to the water line, but we now call it a bond.
The jumper across the water meter is to be removed.
My issue is that I have a metal water meter. I isolated it and it clearly has 0 ohm resistance across the meter. Removing the jumper doesn't stop electricity from flowing through the meter.
In the future, if we lose an overhead neutral from the poco, the return path will be through the water line, through the meter and through the incoming water line which is bonded to neutral in the neighbor's house. If a plumber cuts a line, or a city employee removes a meter, they will break the new return circuit. I don't think being in parallel with a 10 ohm ground rod is going to save them.
What do you think?
