Thread: Can a service panel be considered grounded with only metalli conduit

Our local utility requires a continuous unbroken ground wire from the ground rod through the meter to the neutral buss in the service panel on new construction. Many of the older services we inspect do not have a ground wire from the meter in and rely only on the conduit for grounding. How do you handle this, does the NEC require the continuous ground wire or is this local preference

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The GEC (Grounding Electrode Conductor) is required to be continuous between the first grounding electrode and the service equipment (or meter, depending on where the utility wants it connected).

No splices (except for exothermic welded or irreversible compression connector).

Originally Posted by Jerry Peck

The GEC (Grounding Electrode Conductor) is required to be continuous between the first grounding electrode and the service equipment (or meter, depending on where the utility wants it connected).

No splices (except for exothermic welded or irreversible compression connector).

Let me try a little harder. If the meter is grounded as above,does metallic conduit leading from the meter base to the service panel provide a proper grounding source or does the ground wire have to continue to the service panel?

Yes, provided the metallic conduit and fittings are of the proper type and installed properly.

In that case, "the meter is grounded as above," service equipment requires bonding.

Can you please describe the (GEC) in your meter situation please.
I ask because you appear to be having a hard time describing the equipment.
Where does it start or end, what is it connected to, both ends.
Also what is the conductor/cable and gauge of the cable?
Do not open or touch anything PLEASE!

Random question, is the meter a disconnect? Breakers at the metering box?

Here is a link from Mike H. on grounding and bonding.
http://ecmweb.com/code-basics/ground...nding-part-1-3
As you can see it is in three parts. It is not simple and admittedly to me some took time to be familiar with the full scope of bonding, grounding and the equipment. And that is just single phase current.

PS: Sorry for the editing.

My recollection is that the NEC says that the GEC terminates in the service equipment, but also allows it to terminate in the meter (I don't have my codes with me).

The meter enclosure and the service equipment enclosure are to be bonded together (thus the specificity of grounding bushings in reference service equipment - but keep in mind that grounding bushings are not an approved "continuous" fitting connection).

Also, some utilities like to try to enforce their regulations beyond where their regulations stop and the NEC starts.

Jerry, when you get back, I say when you get back because typically you are away from your PC when you say, (I don't have my codes with me). I would like to clarify something.
At times ground rods and GEC cables are required for both, the meter and service equipment if I am not mistaken.
If you could clarify this it would be much appreciated.

Have a good outing.

Robert,

Sometimes a meter is installed remotely from the service equipment, sometimes a meter is not related to service equipment - either way the metal meter enclosure is required to be grounded.

How the meter is used and wired controls how it is grounded.

Keep in mind that all grounding electrodes installed for a service/structure are required to be bonded together.

Also, only the first GEC from the service equipment is required to be continuous and not spliced.

Originally Posted by Jerry Peck

Robert,

Sometimes a meter is installed remotely from the service equipment, sometimes a meter is not related to service equipment - either way the metal meter enclosure is required to be grounded.

How the meter is used and wired controls how it is grounded.

Keep in mind that all grounding electrodes installed for a service/structure are required to be bonded together.

Also, only the first GEC from the service equipment is required to be continuous and not spliced.

That I understand. Thanks.
When are two ground rods required.

Originally Posted by ROBERT YOUNG

When are two ground rods required.

When using ground rods one must test and document less than 25 ohms to earth ... or install a second ground rod.

Being as few contractors have the proper equipment or use the proper method of testing ... or want to spend the time to only prove there is not less than 25 ohms to ground ... simply drive a second gground rod.

Here is the worst case I've seen: electrical contractor installed the second ground rod 5 feet from the first ground rod (6 feet is the minimum separation between ground rods) ... he grabbed the top of the second ground rod with his Channel Locks (or other brand) and pulled the ground rod out of the ground, moved about 3 feet, asked if this was good, then shoved the ground rod down into the earth ... as I stood there watching in bewilderment.

The sand allowed to rods to be shoved in an pulled back out that easily.

Of course, though, that raised another question - minimum depth.

Originally Posted by Jerry Peck

When using ground rods one must test and document less than 25 ohms to earth ... or install a second ground rod.

Being as few contractors have the proper equipment or use the proper method of testing ... or want to spend the time to only prove there is not less than 25 ohms to ground ... simply drive a second gground rod.

Here is the worst case I've seen: electrical contractor installed the second ground rod 5 feet from the first ground rod (6 feet is the minimum separation between ground rods) ... he grabbed the top of the second ground rod with his Channel Locks (or other brand) and pulled the ground rod out of the ground, moved about 3 feet, asked if this was good, then shoved the ground rod down into the earth ... as I stood there watching in bewilderment.

The sand allowed to rods to be shoved in an pulled back out that easily.

Of course, though, that raised another question - minimum depth.

I think 6 feet is the required minimum depth but material conduction is the essence of the GEC and equipment.

I used a small excavator to remove a ground once. I have even used a car jack.
When the electrician removed the ground rod effortlessly with channel locks he should have considered conductivity.
Senseless grounding at that point.
Wow.

Originally Posted by ROBERT YOUNG

I think 6 feet is the required minimum depth but material conduction is the essence of the GEC and equipment.

The minimum depth to the top of the ground rod is at permanent moisture level, the minimum rod length is 8 feet.

Originally Posted by Jerry Peck

The minimum depth to the top of the ground rod is at permanent moisture level, the minimum rod length is 8 feet.

Just checking to see if you are paying attention.

How deep is minimum moisture level?

Depends.

Originally Posted by Jerry Peck

How deep is minimum moisture level?

Depends.

Conductivity.
Think of this, slab construction ufer is not 8' deep.
Another grounding principle but, the proper conduction exists.

Thanks.

Originally Posted by ROBERT YOUNG

Conductivity.
Think of this, slab construction ufer is not 8' deep.
Another grounding principle but, the proper conduction exists.

Thanks.

A concrete encased electrode is a completely different animal and has completely different requirements.

It's about 'intended'... or 'hopeful' ... 'conductivity to earth' ... as in 'three ground rods are not required', the second, yes - a third, no. If two don't do it, don't bother with a third.

Ground rings are a different matter - typically ground rings around communication power transformers (all the ones I've inspected anyway) have a ground rod at each corner and typically one in the center of each side that exceeds 10 feet (5 foot spacing in the engineered system) with the ground ring conductor exothermically welded to the ground rods. Special enclosures were installed over and around each connection which required a special tool to open (I still have the one the AT&T guys gave me).

Originally Posted by ROBERT YOUNG

In that case, "the meter is grounded as above," service equipment requires bonding.

Can you please describe the (GEC) in your meter situation please.
I ask because you appear to be having a hard time describing the equipment.
Where does it start or end, what is it connected to, both ends.
Also what is the conductor/cable and gauge of the cable?
Do not open or touch anything PLEASE!

Random question, is the meter a disconnect? Breakers at the metering box?

Here is a link from Mike H. on grounding and bonding.
http://ecmweb.com/code-basics/ground...nding-part-1-3
As you can see it is in three parts. It is not simple and admittedly to me some took time to be familiar with the full scope of bonding, grounding and the equipment. And that is just single phase current.

PS: Sorry for the editing.

Robert

This is a simple meter mounted on the outside of the house typically connected to the 100 amp Service Panel for Jerry (main breaker box for most of us) by 1 1/4" ridged conduit with less than a 10 foot run. wire would be #4 copper and #6 ground wire from the ground rod runs unbroken through the meter base and the ridged conduit to the service panel inside the house. grounding bushing are required at the meter base and the service panel.

Is this clearer. This what the utility wants the question is are they adding to the NEC or is this correct?

Thanks enjoy your answers

Don

- - - Updated - - -

Originally Posted by ROBERT YOUNG

In that case, "the meter is grounded as above," service equipment requires bonding.

Can you please describe the (GEC) in your meter situation please.
I ask because you appear to be having a hard time describing the equipment.
Where does it start or end, what is it connected to, both ends.
Also what is the conductor/cable and gauge of the cable?
Do not open or touch anything PLEASE!

Random question, is the meter a disconnect? Breakers at the metering box?

Here is a link from Mike H. on grounding and bonding.
http://ecmweb.com/code-basics/ground...nding-part-1-3
As you can see it is in three parts. It is not simple and admittedly to me some took time to be familiar with the full scope of bonding, grounding and the equipment. And that is just single phase current.

PS: Sorry for the editing.

Robert

This is a simple meter mounted on the outside of the house typically connected to the 100 amp Service Panel for Jerry (main breaker box for most of us) by 1 1/4" ridged conduit with less than a 10 foot run. wire would be #4 copper and #6 ground wire from the ground rod runs unbroken through the meter base and the ridged conduit to the service panel inside the house. grounding bushing are required at the meter base and the service panel.

Is this clearer. This what the utility wants the question is are they adding to the NEC or is this correct?

Thanks enjoy your answers

Don

[QUOTE=Don Hawley;268342]Robert

This is a simple meter mounted on the outside of the house typically connected to the 100 amp Service Panel for Jerry (main breaker box for most of us) by 1 1/4" ridged conduit with less than a 10 foot run. wire would be #4 copper and #6 ground wire from the ground rod runs unbroken through the meter base and the ridged conduit to the service panel inside the house. grounding bushing are required at the meter base and the service panel.

Is this clearer. This what the utility wants the question is are they adding to the NEC or is this correct?

Thanks enjoy your answers

Don /QUOTE]

Thanks!
Jerry says its like trying to to nail jello to a tree. Ha ha ha

Not quite sure but I did run past an article in Mike Holt's site but had to go out for an inspection.
I will try to find the article again later on.

Originally Posted by Jerry Peck

A concrete encased electrode is a completely different animal and has completely different requirements.

I concur.
I think I mentioned that is my post.

NEC 250.24(A)(1)
Grounding electrode conductor must connect the neutral conductor to (a) grounding electrode at the:
1: Service drop
2: Meter enclosure. As in your case.
3: Service disconnect.

A. Either location is fine with the NEC. The rule states that the grounding electrode conductor must connect the service neutral conductor to the grounding electrode at any accessible location, from the load end of the service drop or service lateral up to and including the service disconnecting means [250.24(A)(1)].

If you return to post #5, is the meter the service disconnect or a metering box only?
Sorry I am asking again.

Originally Posted by ROBERT YOUNG

NEC 250.24(A)(1)
Grounding electrode conductor must connect the neutral conductor to (a) grounding electrode at the:
1: Service drop
2: Meter enclosure. As in your case.
3: Service disconnect.

A. Either location is fine with the NEC. The rule states that the grounding electrode conductor must connect the service neutral conductor to the grounding electrode at any accessible location, from the load end of the service drop or service lateral up to and including the service disconnecting means [250.24(A)(1)].

If you return to post #5, is the meter the service disconnect or a metering box only?
Sorry I am asking again.

The first disconnect will be at the service panel (main breaker box)

As to your inquiries "1: Our local utility requires a continuous unbroken ground wire from the ground rod through the meter to the neutral buss in the service panel on new construction. Many of the older services we inspect do not have a ground wire from the meter in and rely only on the conduit for grounding. 2: How do you handle this, 3: does the NEC require the continuous ground wire or is this local preference"

Looks like I have beaten off more than I can chew.
I would handle this by calling a local AHJ.

Originally Posted by Jerry Peck

Robert,

Sometimes a meter is installed remotely from the service equipment, sometimes a meter is not related to service equipment - either way the metal meter enclosure is required to be grounded.

How the meter is used and wired controls how it is grounded.

Keep in mind that all grounding electrodes installed for a service/structure are required to be bonded together.

Also, only the first GEC from the service equipment is required to be continuous and not spliced.

I know this was covered before. If not here at Inspection news, than at your favourite association, well at least mine although I think it was here.
Separate grounding rods placed within the required distance allowed. One for the meter, one for the service equipment.

Sorry to go off thread.

Originally Posted by ROBERT YOUNG

Conductivity.
Think of this, slab construction ufer is not 8' deep.
Another grounding principle but, the proper conduction exists.

Thanks.

250.53 (G) Requires:
-8 foot length of the rod electrode to be in contact with the soil
-Minimum 8 foot driven depth....except when:
----Rock bottom is encountered...it is permitted to be
------driven at an oblique angle (up to 45 degrees) OR
------Buried in a minimum 30 inch deep trench

Donald W. Kane, PE

To Robert Y, some utilities do not allow grounding in the meter socket.

- - - Updated - - -

Originally Posted by Don Hawley

The first disconnect will be at the service panel (main breaker box)

The first disconnect will be the service. It does not need to be a panel. Also a panel can have a main breaker without being a service.

Originally Posted by Jerry Peck

The minimum depth to the top of the ground rod is at permanent moisture level, the minimum rod length is 8 feet.

Can you cite this requirement ? The NEC only says flush or below grade and at least 8 foot in contact with the soil.