Its grounded or not

[Bill Wieczorek]

The home in question is only 3 YO. The questions is this.The box is grounded outside with a rod. Inside they ran a green wire in a piece of conduit (marked ground) to the copper plumbing and jumped it to the copper pipe going out thru the foundation. The problem is this house has a well and there's a piece of plastic between the copper and where the pipe goes out so its not grounded in essence. Is the grounding rod next to the box outside going to be sufficient.
I'm thinking they have done the grounding via the copper pipe if city water was made available at some point. Thoughts ???

[Jim Port]

From your description it sounds like they jumpered over the plastic section and a metal line leaves the foundation to the well. Is this correct? Is the metal outside the foundation in earth for 10' or more?

[Jerry Peck]

Inside they ran a green wire in a piece of conduit (marked ground) to the copper plumbing and jumped it to the copper pipe going out thru the foundation.

What type of conduit? PVC or metal? Makes a big difference.

I'm thinking that may be their interior metal water piping bond conductor, that it is not for "grounding" but for "bonding". Yeah, I know it was marked "ground", but whoever marked it may not know the difference.

[Robert Meier]

What's "the box" and where exactly is the ground rod terminated?

[Bill Wieczorek]

What they did Jim was to jump from what I thought to be the ground wire (green) and marked (ground) on a section of metal conduit. They used a thick piece of copper and ran it to the copper plumbing pipe that goes to the connection from the well in the front yard which is plastic, that won't ground anything. As jerry said it may be marked incorrectly.

The box I referred to is the meter casing where power enters the house. That has a ground rod with a wire coming from it going to the rod in the ground.

Does this clarify.

[Jerry Peck]

Bill,


What type of conduit? PVC or metal? Makes a big difference.

Metal conduit or plastic conduit?

I ask because if the conduit is metal, and if that is a grounding wire, then the metal conduit needs to be bonded to the wire at both ends of the metal conduit, if PVC it does not matter.

[Bill Wieczorek]

Jerry, it is metal conduit.

[Jim Port]

I would say unless there is proof that the single rod electrode was less than 25 ohms, it needs to be supplemented with another rod. It does not sound like the water line connections are doing anything.

[Eric Barker]

Bill, I also think that the connection to the water pipe is primarily for bonding. Ideally there would be two ground rods but the only time I can remember seeing two is on my house. Even if a grounding conductor was fastened to an incoming metal water pipe (on a private well system) I would wonder how far that pipe extended out into the soil before reverting to plastic pipe. Let's face it, very often we're just not sure of what was done.

As you know there is not much regulation over electricians around here and getting some of them to understand electricity can be a neat trick. A local inspector who I highly regard has given up on commenting on improper grounding and bonding because it's such an uphill battle with contractors who have no clue what he's talking about. It's a real problem and I understand where he's coming from. I gave up on CO testing for the very same reason.

[cuba_pete]

The problem is this house has a well and there's a piece of plastic between the copper and where the pipe goes out so its not grounded in essence...Thoughts ???

Sections 250.104(A)(1) and (A)(3) require the metal water piping system of a building or structure to be bonded to the service equipment or grounding electrode conductor or, where supplied by a feeder or branch circuit, to the building or structure disconnecting means or grounding electrode conductor. Where it cannot be reasonably concluded that the hot and cold water pipes are reliably bonded through mechanical connections, an electrical bonding jumper is required to ensure that this connection is made. Isolated sections of metal piping (such as may be used for a plumbing fixture connection) that are connected to an overall nonmetallic water piping system are not subject to the requirements of 250.104(A). The isolated sections are not a metal water piping system. The special installation requirements provided in 250.64(A), (B), and (E) also apply to the water piping bonding jumper.

Also may be applicable:
250.68(C)(1) Interior metal water piping located not more than 1.52 m (5 ft) from the point of entrance to the building shall be permitted to be used as a conductor to interconnect electrodes that are part of the grounding electrode system.

I cannot find an NEC reference for mandatory labeling of the water piping bond. Labeling it as "ground" is probably a lot more explanatory that labeling it "bond" in this case. Our family lake cabin has this label on the water pipe bond. I understood it, but I guess we cannot assume that everyone would.

There is an excellent paper which encompasses this subject and is written just for home inspectors:
http://www.prospex.us/DOCS/ELECTRICAL/ELECTRICAL%20SYSTEM%20BONDING%20AND%20GROUNDING%20 .pdf

I shudder to think that home inspectors have to explain these things to electricians and electrical contractors.

[Garry Blankenship]

Grounded ~ probably; legally grounded ~ probably not. Bonding to the ground path is encouraged, but isolated auxillary ground paths are discouraged by the code. If your project is only 3 years old, it likely has a main service bonding jumper and the ground path established there is supposed to be maintained as an exclusive path. Aside from the undesired effect of creating multiple ground paths, it is a witch hunt to really know how effective an isolated ground point is. A ground rod driven in a really dry area could be totally ineffective.