ground rod loop

[Danny R Chavez]

The last service I had inspected the inspector asked me to run a loop to a single ground rod. My understanding of the necessity for the loop is on a two rod grounding system it eliminates the possibility of a difference on potential between the two rods. I don't understand what I gain in looping to a single rod. Will someone please educate me before I argue with the inspector on my next service.

 

[Dennis Alwon]

The code requires 2 rods unless you can show 25 ohms on one rod. There is absolutely no reason to loop the grounding electrode conductor back to the service. Basically you are installing a parallel conductor-- don't think it can hurt but it is not required.

 

[George Stolz]

My understanding of the necessity for the loop is on a two rod grounding system it eliminates the possibility of a difference on potential between the two rods.

Why would you care about the potential of a ground rod?

The inspector is respectfully out to lunch - er - requesting odd things not required by the NEC.

 

[infinity]

Either he's enforcing a local code or making up his own. As stated this is not an NEC requirement.

 

[iwire]

I agree with the others, there is no NEC requirement for a loop for one or a dozen electrodes.

 

[roger]

The inspector is respectfully out to lunch - er - requesting odd things not required by the NEC.

Agreed.

Roger

 

[iwire]

As this graphic shows there are many options as far as connecting electrodes but none of them have to be looped.

 

[kwired]

Difference of potential between the rods? They will be same potential if connected together, aside from any resistance in the connecting conductor, but that will be negligible for most practical purposes.

 

[Danny R Chavez]

Thanks for the input

Thanks for the input

In upstate NY the practice is if there is a city water system you must bond to it and drive one rod, in rural applications without city water two ground rods must be driven and the conductor must be run from the panel to the rods in a loop both ends are attached at the neutral bar. Never did understand the difference in potential argument if they both ends attach at the same point in the panel. Then it wasn't my place to discuss it but times have changed.

 

[kwired]

In upstate NY the practice is if there is a city water system you must bond to it and drive one rod, in rural applications without city water two ground rods must be driven and the conductor must be run from the panel to the rods in a loop both ends are attached at the neutral bar. Never did understand the difference in potential argument if they both ends attach at the same point in the panel. Then it wasn't my place to discuss it but times have changed.

If somebody is requiring that, they have a misunderstanding. That loop coming back has very little benefit - especially for a typical rod type electrode that likely has much higher impedance to earth than the impedance of the conductor supplying it.

 

[GoldDigger]

If somebody is requiring that, they have a misunderstanding. That loop coming back has very little benefit - especially for a typical rod type electrode that likely has much higher impedance to earth than the impedance of the conductor supplying it.

The only possible benefit that I see is, like the case for ring circuits in the UK, if one conductor is accidentally cut, the ground connection will still be there.

 

[kwired]

The only possible benefit that I see is, like the case for ring circuits in the UK, if one conductor is accidentally cut, the ground connection will still be there.

How will you ever know if one or both have gone bad, outside of physically seeing it disconnected or something like that?

When it comes to grounding electrode conductors, there are rules for connections and protection and connection devices are often required to be listed for grounding that do reasonably assure there will be good continuity of the conductor.

 

[RLyons]

I've Adapted the loop method due to certain inspectors "requiring" it. Between inspectors and utility grounding requirements I stick with overkill rather than to argue with them as my time cost more than the cost of the extra copper.

 

[kwired]

I've Adapted the loop method due to certain inspectors "requiring" it. Between inspectors and utility grounding requirements I stick with overkill rather than to argue with them as my time cost more than the cost of the extra copper.

Don't you also save some time if you do not install the loop?

 

[Joe Villani]

Ground rod Loop

Ground rod Loop

One of the utility companies in my area, NYSEG, shows in their spec book the ground rods looped and back to the service disconnect.

Often the electrical inspector in the area has to inspect both to the NEC and the utility company spec.

This is enables them to issue a "Cut in card" or "temp" and not having the utility company to preform an additional inspection.

Check your utility companies spec book and see what they are requiring.

This is more than likely not an NEC issue. More than likely the inspector is enforcing a utility company spec.

Joe Villani

 

[kwired]

One of the utility companies in my area, NYSEG, shows in their spec book the ground rods looped and back to the service disconnect.

Often the electrical inspector in the area has to inspect both to the NEC and the utility company spec.

This is enables them to issue a "Cut in card" or "temp" and not having the utility company to preform an additional inspection.

Check your utility companies spec book and see what they are requiring.

This is more than likely not an NEC issue. More than likely the inspector is enforcing a utility company spec.

Joe Villani

I don't understand why a POCO should care what you do with a service disconnect. A meter socket I can understand. Even it the socket it not theirs the meter that plugs into it generally is.

NEC is not too specific on where to connect the GEC - can be anywhere from service disconnect to the connection of service drop or lateral.