Thread: Grounding rod attached to your electric meter panel

When did is it become code to have a grounding rod attached to your electric meter panel?

Our home was built in 1980 and this was flagged in a home inspection for not having one.

Is it not grandfathered in if it did not become code til about 10 years ago?

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Grounding has always been required, certainly long before your house was built.
There may be grounding present, but it seems the inspector was unable to determine that, so he is calling for a closer look. It is a serious safety concern.

From the 1978 NEC:
- 250-81. Grounding Electrode System. If available on the premises at each building or structure served, each item (a) through (d) below shall be bonded together to form the grounding electrode system. The bonding jumper shall be sized in accordance with Section 250-79(c) and shall be connected in the manner specified in Section 250-115.
- - (a) A metal underground water pipe in direct contact with the earth for 10 feet or more ...
- - (b) The metal frame of the building, where effectively grounded.
- - (c) An electrode encased by at least 2 inches of concrete, ...
- - (d) A ground ring encircling the building or structure, in direct contact with the earth at a depth below earth surface not less than 2-1/2 feet, consisting of at least 20 feet of bare copper conductor not smaller than No. 2 AWG.
- 250.83. Made and Other Electrodes. Where none of the electrodes specified in Section 250-81 is available, one or more of the electrodes specified in (s) through (d) below shall be used. (blah, blah, blah continues)
- - (a) An electrically continuous metal underground gas piping system ...
- - (b) Other local metal underground systems or structures, such as piping systems and underground tanks.
- - (c) Rod and Pipe Electrodes. Rod and pipe electrodes shall not be less than 8 feet ...
- - (d) Plate Electrodes. Each plate electrode shall expose not less than 2 square feet of surface to the exterior soil. (blah, blah, blah continues)

What does the above mean?

It means that if no other ground can be verified, than one of the electrodes in 250.83 shall be installed.

If the inspector did not find any evidence of grounding, they recommended 250-81 be followed (i.e., a ground rod be installed as that is the easiest type of electrode to install, of electrodes covered in 250-81).

You could have the electrical contractor verify that your service is already properly grounded to what was required back then, but ... my guess is that it will be less expensive to install a ground rod.

On Friday I was inspecting a service to a lift station, the engineer specified a minimum of 3 ground rods a minimum of 10 feet apart with 25 ohms or less to ground each, or, install additional ground rods. I asked the electrician to document that there there was 25 ohms to ground at each ground rod, or, install additional ground rods. I explained to the contractor that is usually is less expensive and easier to install the additional ground rods than to verify that each ground rod has less than 25 ohms to ground - the contractor called the electrical contractor who said they would just add additional ground rods because that is easier than documenting 25 ohms to ground or less and then not getting 25 ohms or less and having to add the additional ground rods anyway - works for me is what I told the contractor.

Originally Posted by Jerry Peck

From the 1978 NEC:
- 250-81. Grounding Electrode System. If available on the premises at each building or structure served, each item (a) through (d) below shall be bonded together to form the grounding electrode system. The bonding jumper shall be sized in accordance with Section 250-79(c) and shall be connected in the manner specified in Section 250-115.
- - (a) A metal underground water pipe in direct contact with the earth for 10 feet or more ...
- - (b) The metal frame of the building, where effectively grounded.
- - (c) An electrode encased by at least 2 inches of concrete, ...
- - (d) A ground ring encircling the building or structure, in direct contact with the earth at a depth below earth surface not less than 2-1/2 feet, consisting of at least 20 feet of bare copper conductor not smaller than No. 2 AWG.
- 250.83. Made and Other Electrodes. Where none of the electrodes specified in Section 250-81 is available, one or more of the electrodes specified in (s) through (d) below shall be used. (blah, blah, blah continues)
- - (a) An electrically continuous metal underground gas piping system ...
- - (b) Other local metal underground systems or structures, such as piping systems and underground tanks.
- - (c) Rod and Pipe Electrodes. Rod and pipe electrodes shall not be less than 8 feet ...
- - (d) Plate Electrodes. Each plate electrode shall expose not less than 2 square feet of surface to the exterior soil. (blah, blah, blah continues)

What does the above mean?

It means that if no other ground can be verified, than one of the electrodes in 250.83 shall be installed.

If the inspector did not find any evidence of grounding, they recommended 250-81 be followed (i.e., a ground rod be installed as that is the easiest type of electrode to install, of electrodes covered in 250-81).

You could have the electrical contractor verify that your service is already properly grounded to what was required back then, but ... my guess is that it will be less expensive to install a ground rod.

On Friday I was inspecting a service to a lift station, the engineer specified a minimum of 3 ground rods a minimum of 10 feet apart with 25 ohms or less to ground each, or, install additional ground rods. I asked the electrician to document that there there was 25 ohms to ground at each ground rod, or, install additional ground rods. I explained to the contractor that is usually is less expensive and easier to install the additional ground rods than to verify that each ground rod has less than 25 ohms to ground - the contractor called the electrical contractor who said they would just add additional ground rods because that is easier than documenting 25 ohms to ground or less and then not getting 25 ohms or less and having to add the additional ground rods anyway - works for me is what I told the contractor.

What is the difficulty in documenting less than 25 ohms

Originally Posted by Phil brody

What is the difficulty in documenting less than 25 ohms

Using the right equipment and doing the test properly.

Originally Posted by Jerry Peck

Using the right equipment and doing the test properly.

I guess there might be a geographical difference to the equipment carried typically by the electrician and typical rod performance with soil types, but understandably to pacify the engineer 1st - quality of installation 2nd. Since this was a lift station enough said.