Grounding to Water Pipes

[safetyman2010]

I was recently asked a question by our water meter crew regarding residential grounding to water pipes and the changing of water meters. I work for a public agency that, among other things, provides drinking water to a large metropolitan city. One of our crews was changing meters in a residential area and found a ground wire attached to the pipe near the water meter. Not wanting to be shocked or electrocuted, they requested the homeowner have the power to their house shut off prior to the meter change out. The local electrical utility assisted in the shut-off.

My question: Is there a way to determine if there is current flow in/on a water pipe that has a visible ground, or nonvisible ground, attached to it? it is not convenient nor feasible to request our customers to shut off power to their residence or structure for each meter change; additionally, that residence or structure may not be the source of electricity.

 

[bphgravity]

My question: Is there a way to determine if there is current flow in/on a water pipe that has a visible ground, or nonvisible ground, attached to it? it is not convenient nor feasible to request our customers to shut off power to their residence or structure for each meter change; additionally, that residence or structure may not be the source of electricity.

There will always be current flow on a community underground water pipe. How much can vary greatly depending on specific grounding arrangement of surrounding services and amount of loads operating at the time of contact.

Even with the power off, if the utility grounded (neutral) conductor remains connected; current can flow over the grounded parts. Current may be present from a neighbor?s service or even remotely grounded services.

 

[don_resqcapt19]

Some water companies require that their employees use a temporary bonding jumper around the meter or other pipe part that is being replaced. You could use a clamp around amp meter to check for current but that won't tell you if there is a real hazard to your employees. If the grounded conductor is in good condition and there is current on the water pipe, there will be very little voltage between the pipe sections when they are disconnected. However, even with the same amount of current you could have a fatal voltage between the disconnected pipes if the grounded conductor is open.
Don

 

[hockeyoligist2]

A few years back I had a water pipe that I kept geting shocked on, called POCO and they shut down all the power for miles up the road,still had 75 V, I was the end of the line for the CO-OP. Duke was 2 miles the other way. Bonding it to my ground rod didn't help. So I finally made use of it. I connected a Light to it and to the ground rod and the shocks went away and I had a free night light!

 

[problemsolver600]

Bonding Jumper

Bonding Jumper

Most AHJ's in the Chicago area require electrical bonding to the water lines, but also require a bonding jumper be installed at the meter to make meter replacement safe. Even if the electrical system is grounded after the meter, the bond is required "just in case".
The other side was a home inspection in Bourbonnais, IL where the inspector required a bonding jumper on a 1' pvc feed, because!?