Ufer distance from ground rod

[CCallahan]

On a jobsite where conflicting information is being thrown around (I'm sure many of you are familiar) and it has me doubting myself.

Couple questions...

1) Does a ground rod have to be a minimum of 6' away from the ufer ground?

2) Does the ground rod and ufer need to be bonded together before connecting into the panelboard? When the code says they must all be bonded together does that include the neutral/ground bus in the panel or no?

3) The new structure being built is going to store paint. I have read that in NFPA 780 it requires the ground rods to be apart the same distance as length of the rods to help with lightning dispersion for places with volatile liquids. However, I don't have a copy of the 780 and we typically go off NFPA 70 (which states no less than 6' apart) so what should be my thinking on this?

 

[Dennis Alwon]

On a jobsite where conflicting information is being thrown around (I'm sure many of you are familiar) and it has me doubting myself.

Couple questions...

1) Does a ground rod have to be a minimum of 6' away from the ufer ground?

You do not need a ground rod if you have a ufer so no it does not need to be 6' away although if you use the rod it would be beneficial to keep it 6' away

2) Does the ground rod and ufer need to be bonded together before connecting into the panelboard? When the code says they must all be bonded together does that include the neutral/ground bus in the panel or no?

No the ufer and rod can be connected in the panel

3) The new structure being built is going to store paint. I have read that in NFPA 780 it requires the ground rods to be apart the same distance as length of the rods to help with lightning dispersion for places with volatile liquids. However, I don't have a copy of the 780 and we typically go off NFPA 70 (which states no less than 6' apart) so what should be my thinking on this?

The NEC req. 6' or more I don't know about NFPA 780

 

[Smart $]

Regarding 2)...

The NEC does not prohibit more than one GEC.

Bonded together includes the grounded conductor if at or before the service disconnecting means. It does not if after the service disconnecting means, such as at a separate building or structure supplied by a branch or feeder circuit, or for an auxiliary grounding electrode.

 

[CCallahan]

You do not need a ground rod if you have a ufer so no it does not need to be 6' away although if you use the rod it would be beneficial to keep it 6' away


No the ufer and rod can be connected in the panel



The NEC req. 6' or more I don't know about NFPA 780

I believe local code is requiring the use of both however I will find out for sure very soon. Also, I assume since you say beneficial it is not required per NEC? I could not find any place in the 2014 that talked about this.

Regarding 2)...

The NEC does not prohibit more than one GEC.

Bonded together includes the grounded conductor if at or before the service disconnecting means. It does not if after the service disconnecting means, such as at a separate building or structure supplied by a branch or feeder circuit, or for an auxiliary grounding electrode.

The last statement contradicts the previous Moderator's response. Can anyone supply me with an article number for reference on this?

 

[Smart $]

...
The last statement contradicts the previous Moderator's response. Can anyone supply me with an article number for reference on this?

For bonding at or before the service disconnecting means, 250.24(D).

For separate buildings and structures... 250.32(D)

 

[gsstaley@sbcglobal.net]

Can I get a definition from the group for a U-fer ground, and it's relevence as compared to a ground rod?

 

[kwired]

Can I get a definition from the group for a U-fer ground, and it's relevence as compared to a ground rod?

U-fer is a name that comes from the founder of this electrode "Herbert G. Ufer". See this article for more.

NEC calls it a Concrete Encased Elecrode, and defines minimum construction requirements to consider an object to qualify as a "CEE".

NEC also has a list of electrodes that if present must be used as an electrode and the CEE is on that list. Ground rods and other "made" electrodes are only required when there is no other electrodes present, but you have a choice of which "made" electrode you wish to use, ground rods just happen to be the most convenient and are also reasonable when it comes to cost and are the most preferred for those reasons.

If you have a CEE, NEC doesn't require also using rod(s) but at same time does not prohibit them. Keeping the rod 6 feet away from any other elecrode will help maximize the effectiveness of that rod, at closer distances you get more overlap of the "sphere of influence" of said electrodes which minimizes the maximum potential effectiveness you may be able to achieve. Some will tell you you need even more then six feet, but that is the range where effectiveness typically starts to drop pretty rapidly if it hasn't dropped pretty significantly already

 

[gsstaley@sbcglobal.net]

Great, thanks. Now if my rebar and concrete-encased electrode are within a vapor barrier with no true contact with earth, it's purpose (or use) without a ground rod?
Sorry to jump in someone else's post!

 

[Smart $]

Great, thanks. Now if my rebar and concrete-encased electrode are within a vapor barrier with no true contact with earth, it's purpose (or use) without a ground rod?

It doesn't qualify as an electrode if the concrete is not in direct contact with earth.

 

[kwired]

Can I get a definition from the group for a U-fer ground, and it's relevence as compared to a ground rod?

Great, thanks. Now if my rebar and concrete-encased electrode are within a vapor barrier with no true contact with earth, it's purpose (or use) without a ground rod?
Sorry to jump in someone else's post!

As Smart$ mentioned if isolated from earth it is not a qualifying electrode. But if it is in direct contact with earth is usually (more like almost always) much lower resistance to earth electrode then a typical ground rod. Much more surface contact with earth then there is with a rod.

 

[fmtjfw]

On a jobsite where conflicting information is being thrown around (I'm sure many of you are familiar) and it has me doubting myself.

Couple questions...

1) Does a ground rod have to be a minimum of 6' away from the ufer ground?

2) Does the ground rod and ufer need to be bonded together before connecting into the panelboard? When the code says they must all be bonded together does that include the neutral/ground bus in the panel or no?

3) The new structure being built is going to store paint. I have read that in NFPA 780 it requires the ground rods to be apart the same distance as length of the rods to help with lightning dispersion for places with volatile liquids. However, I don't have a copy of the 780 and we typically go off NFPA 70 (which states no less than 6' apart) so what should be my thinking on this?

1) Which part of the UFER?

 

[GoldDigger]

1) Which part of the UFER?

Any part of the concrete that shares the rebar system with electrical continuity.
If you use a wire UFER at one end of the building and do not connect it to the rebar system (or the rebar is insulated) you might not have much of a zone of influence effect at the other end of the building.