Required to use ufer ground?

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  #1  
Old 03-15-14, 08:51 PM
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Required to use ufer ground?

I have a new house (2013) in Pasco, FL. The house has a meter on one side and the incoming service wires go from the meter across the attic to the other side of the house to the garage where the service panel is located. Along with the main service wires from the meter pan is a stranded ground wire that runs to the other side of the house and down the outside (under stucco) then out the stucco at the bottom of the house, There it was connected to a ground rod (just one) and continued on to rebar coming out of the foundation (ufer ground I assume).

At some point, the ground wire was partially broken so only half the strands were continuous. I had an electrician come out to see if they could repair it in place. The recommended simply running two new ground rod back on the meter side of the house and a new grounding conductor from the meter pan to the rods (to be placed 8 ft apart). I agreed this would be fine. I actually thought this might be better since it presented a shorter path to ground for incoming surges over the mains.

Anyway, they went ahead and did this and everything was fine. I asked about the old ufer ground because I saw him remove the old ground wire from the meter pan when he attached the new one for the new ground rods. He said I did not need to have the ufer connected to the grounding system.

In some various info I've read online I came across something in the code that said if an ufer ground was present in the building, it HAD to be connected to the grounding system. Is this true? If I have two ground rods, am I still required to have the ufer ground connected?

Thanks for any input anyone may have on this topic.
 
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  #2  
Old 03-15-14, 09:20 PM
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Your grounding electrode system must include at least one Ufer (rebar) ground (if any), at least one one cold water pipe exiting the house underground (if metal), two ground rods at least 6 feet apart (one if a certain electrical impedance test qualifies it) and all other ground rods about that building and presently in use to ground other things like antennas.

If the building was built before a certain date (I don't recall) and there are no exposed rebars in below grade concrete components, then that building is considered to not possess a Ufer ground. If there was/were a Ufer ground(s) in use, one must continue to be included in your grounding electrode system regardless of when the building was built.

The existing Ufer ground may be readily reconnected simply by attaching its wire (a grounding electrode conductor) (using a clamp) to the new GEC going to the new ground rod.
 

Last edited by AllanJ; 03-15-14 at 09:35 PM.
  #3  
Old 03-15-14, 11:05 PM
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Thanks. Unfortunately, the old ground wire (from the ufer) was partially severed just before its connection to the ufer rebar. The driving of two new ground rods was the alternative to trying to cad-weld the old wire to repair it since there was very little wire exposed outside the stucco. Also, I believe they cut the old wire inside the meter pan so I don't know if I could (according to code) clamp a new wire onto the old ufer wire to extend it and then again clamp it to the new GEC. Would it need to be a special clamp (irreversible) or cad-weld for both those connections (1 to extend it and 2 to connect to the new GEC)? Could the old GEC (from the ufer) simply be connected to the meter pan since the new GEC is also connected to the meter pan? Does that count as continuity for code purposes?
 
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Old 03-15-14, 11:22 PM
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You are correct, any splices need to be irreversible or thermal welded like a Cadweld.
 
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Old 03-21-14, 04:12 PM
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Here's some additional information. Upon further inspection of the old grounding rod and conductor, I noticed the old ground wire from the meter pan was clamped to the old ground rod. Another ground wire was also clamped to the old ground rod and went directly into the concrete (Ufer ground I assume). That is, there was no exposed rebar from the foundation -- the wire went directly into the concrete footer/foundation where I assume it was connected to some rebar.

Upon further reading about the requirement of an ufer ground, I noticed this statement from the NEC code:

Exception: Concrete-encased electrodes of existing buildings or structures shall not be required to be part of the grounding electrode system where the steel reinforcing bars or rods are not accessible for use without disturbing the
concrete.

Does this change the requirement for an ufer ground in my case? Even though it was originally installed at build time, there is no exposed rebar or reinforcing bar to attach a new GEC to. Yes, I could clamp to the wire coming out of the concrete and connect that back to my new grounding rod(s), but now I'm not sure that's required in light of this statement.
 
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Old 03-21-14, 07:24 PM
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The connection to the rebar can be encased by the concrete.
 
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Old 03-21-14, 08:45 PM
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Thanks. I don't have any doubt that it's ok for the connection to the rebar to have been originally encased in concrete, I'm just wondering about how this would affect my case now that the ground wire must be re-run.

That is, there is currently no exposed rebar or reinforcing rod outside the foundation or footer wall to attach to. So even though the house had an ufer ground originally installed, in the case where the ground wire going into the concrete was severed, is it still required to connect an ufer ground when re-doing the grounding system given that it's no longer possible to connect to the concrete encased rebar "without disturbing the concrete." (let's assume the wire coming from the concrete was severed too close to the concrete to allow for either an irreversible splice or cadweld).
 
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Old 03-21-14, 09:31 PM
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If the house was built or any below-grade reinforced concrete components were added after that edition of the NEC was published then you need the Ufer ground. (According to someone replying in another forum) the lack of a protruding rebar would have then been regarded as an error in construction of course requiring correction.

In your case I would reconnect new grounding electrode conductor to the existing ground wire stub end coming out of the foundation, which would necessitate only a minuscule disturbing of concrete.

If A is bonded to B and B is bonded to C then A is bonded to C.
 
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Old 03-22-14, 03:21 AM
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I do not do new houses . Rarely , I will work on a repair on a house .

So , I am going to display my ignorance .

What is a Ufer ground ? Is that strictly a residential term ? Is it new to the 2014 NEC ?

God bless
Wyr
 
  #10  
Old 03-22-14, 05:53 AM
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What we are discussing here is correctly called a "concrete encased electrode".

The Ufer ground, which uses CEEs, was promoted by someone named Ufer.

Technically a Ufer grounding system may require more than one CEE.

The NEC requires one CEE if CEEs are applicable to the structure.

Ufer is often used loosely to refer to just one CEE and I am guilty of using the term loosely here.

Also, technically, a correct CEE has at least ten feet worth of bonded rebar in the concrete structural element. The usual practice of steel tie wraps where rebars intersect will accomplish this bonding. Unless an electrical inspection was required before the concrete was poured, the CEE is assumed to be correct unless inspection after the pour suggests otherwise.

It has been said (I haven't seen it) that a lightning strike that reaches the grounding electrode system containing a CEE may utilize the conductivity provided by the omnipresent moisture in a below-trade concrete building component and in so doing vaporize the moisture and cause that component to split, possibly explosively. Nevertheless the NEC requirements for CEEs still stands.
 

Last edited by AllanJ; 03-22-14 at 07:55 AM.
  #11  
Old 03-23-14, 03:05 AM
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Thank you , I just call it a re-bar ground .

God bless
Wyr
 
  #12  
Old 03-24-14, 07:46 AM
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The house's original CEE was clamped to the original ground rod with an acorn clamp. A separate wire was then run from the old ground rod (using a second acorn clamp) to the meter pan. That was the original setup when the house was built.

Since I am required to include the CEE in the new grounding system (2 new rods on the other side of the house from the old rod), can I leave the original CEE-to-rod acorn-clamp connection in place and clamp a new #4 wire to the old rod and run that over to one of the new rods and clamp it to one of them? That would essentially tie the old rod to the two new rods, and the old rod would be connected to the CEE.

The question about this method is that the new ground wire would be continuous from the meter pan to the first two ground rods, but not to the third rod or CEE. Of course, in the original installation, it wasn't a continuous wire from the CEE to the meter pan -- the two separate wires were both clamped separately to the original ground rod.
 
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Old 03-24-14, 11:31 AM
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You have one grounding electrode conductor running unspliced from the panel to a grounding electrode (here, a ground rod). Additional GEC may be added on as needed to bond additional grounding electrodes.

If your service wire size is such that the re-bar ground needs a #6 wire then you may run that from the rebar to the nearest point on an existing #6 GEC and be done. But if you need a #4 GEC from the re-bar, you need #4 or equivalent worth of GEC cross sectional area going back to the panel. For example a #4 from re-bar to somewhere on an existing GEC and from that point a second #6 twisted more or less about the first and going the rest of the way to the panel.
 
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Old 03-24-14, 01:28 PM
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I thought the (second) electricians put in #4 solid GEC from the meter to the two new ground rods, and I believe the original GEC (stranded) was #4 as well, so I was just thinking I could run a solid #4 from the old ground rod (where the CEE is connected) over to the new ground rod to create one cohesive grounding system.
 
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Old 03-24-14, 08:12 PM
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Yes, if you already have #4 copper grounding electrode conductor from the panel to some grounding electrodes then you can add on more #4 GEC as needed without modifying that existing GEC.

The maximum size GEC to ground rods ever required is #6. No. 8 can be used in a very small number of cases. Larger is okay but overkill. The GEC to re-bar and water pipe grounding electrodes may sometimes have to be larger.
 
  #16  
Old 03-24-14, 09:57 PM
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Thanks -- good info. I figure I'll just go with #4 to be sure even though it may cost a bit more. Unfortunately, it's about 80 ft. from the side of the house where the original CEE/ground rod is located over to the other side of the house where the meter pan and new ground rods are.

The sad part is that there is already a piece of stranded #4 making most of that run, but the cost of c-taps and a compression tool to connect to it on both ends would be just about as much as buying 80 ft of #4 solid copper for a completely new run with no splices. If I didn't need the irreversible splices, it would be a no-brainer, but I believe an entirely new run will still be the cheapest (and cleanest) solution.

Thanks again for all the info.
 
  #17  
Old 03-24-14, 10:32 PM
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You might be able to find a contractor with the crimp tool to fix this for you.
 
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Old 03-25-14, 05:37 AM
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Do you have the know how (easily learned) to solder the splices you make to achieve your complete grounding electrode system? Soldered connections never lose conductivity due to oxidation i.e. they outlast any other method. They are also hard to take apart.

A medium sized soldering gun (100 watts) can handle #4 copper wire and will come in handy for other electronic and electrical work too. You can also use a soldering tip meant for a propane torch.

Make the splice on the GEC about 6 inches away from a ground rod rather than at the ground rod so as to reduce the heating requirements to achieve the soldered joint.

Soldered connections need to be physically sound, namely you should loop or twist the joint so it can't slide around or fall apart just before you solder it.

Sand the wires first to be sure any oxidation is removed. Use solder specifically meant for electrical work (lead containing 60/40). Do not use plumbing flux or paste.

You may need the blowtorch soldering tip (more heat) or the crimping tool to remake the damaged connection to the re-bar.


.
 
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Old 03-25-14, 10:56 AM
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I am doubtful solder would be accepted. Here is what the NEC says:

250.8 Connection of Grounding and Bonding Equipment.
(A) Permitted Methods. Equipment grounding conductors,
grounding electrode conductors, and bonding jumpers
shall be connected by one of the following means:
(1) Listed pressure connectors
(2) Terminal bars
(3) Pressure connectors listed as grounding and bonding
equipment
(4) Exothermic welding process
(5) Machine screw-type fasteners that engage not less than
two threads or are secured with a nut
(6) Thread-forming machine screws that engage not less
than two threads in the enclosure
(7) Connections that are part of a listed assembly
(8) Other listed means
(B) Methods Not Permitted. Connection devices or fittings
that depend solely on solder shall not be used.
 
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Old 03-25-14, 01:20 PM
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That's ok, I can solder but probably wouldn't. It's interesting to see all those accepted methods, though. I was under the impression that the only two methods were "irreversible" compression connections (crimped like c-taps) and exothermic (like Cadwelds). The "machine screw" based clamps is interesting. Would a split-bolt connection be classified as a "machine screw type fastener"? Or are these methods only to be used in reference to connecting a wire to something rather than "splicing" two wires together?
 
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Old 03-25-14, 01:27 PM
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Split bolts are fine for a tap, but the GEC must be one piece or Cadweld or irreversible spliced.
 
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Old 03-25-14, 01:45 PM
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Ok, so 250.8 (and all of the methods it mentions) refers to "connections" for the GEC, not "splices," correct?

I think AllanJ's response about soldering was regarding the splicing I would need to do to repair a partial break in my old GEC, although I don't know if soldering would be acceptable under the NEC for splicing, would it?
 
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Old 03-25-14, 02:29 PM
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Hmmm. What does relying solely on solder mean?

I intended to suggest solder for all types of wire to wire connections. Due to the larger amount of heat required, I suggest that soldering not be done directly to a ground rod but rather the usual clamp be used.

I would interpret a threaded U bolt clamp as a machine screw and nut type connector.

I find it hard to believe that if I drove a ground rod at the other end of the house for my TV antenna, then a GEC segment simply clamped to the nearest point on the previously existing previously approved grounded electrode system would cancel the approval.
 

Last edited by AllanJ; 03-25-14 at 03:06 PM.
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Old 03-25-14, 03:31 PM
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I find it hard to believe that if I drove a ground rod at the other end of the house for my TV antenna, then a GEC segment simply clamped to the nearest point on the previously existing previously approved grounded electrode system would cancel the approval.


Now I think I'm confused. My case is similar to what you just described. Since my original CEE is currently clamped to the old ground rod and my meter pan is clamped to two new ground rods, I was thinking I could connect the CEE to the new grounding system (the two new rods) by running a new wire between the old rod and one of the new rods, simply acorn-clamped at each end. So now is that not an NEC-approved way of accomplishing that?
 
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Old 03-25-14, 06:15 PM
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That would be a jumper between the two electrodes and could be connect to the existing GECs with a split bolt.
 
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Old 03-25-14, 07:16 PM
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Now I think I'm confused. ...
(translation) I interpret the NEC as, starting with the two new ground rods and unspliced GEC to the panel that your electrician installed and deemed sufficient, additional grounding electrodes may be bonded using additional GEC segments clamped/tapped/spliced/U-bolted onto one another.

So I would go ahead and simply connect the new wire just long enough be a jumper between the rods as you described, although I would prefer wire to wire connections at the ends rather than connect the new wire directly to a rod.
 
  #27  
Old 03-25-14, 07:31 PM
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Thanks. At least I now have a way to re-connect the CEE to the system as required without having to get a compression tool or a Cadweld. Of course, I still need to buy 100' of #4 copper.
 
  #28  
Old 03-26-14, 08:48 AM
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Have you figure out how to repair where the GEC is frayed entering the concrete member? You may have to chip away at least a little concrete to expose enough solid copper.

You may need to crimp something on there which would favor using crimp connections for all the other needed joints as well.

How much of the old GEC do you still have? How far will that stretch? How thick is it? The maximum size of GEC to a concrete encased electrode ever needed is #4 copper, for services with 2/O copper (typical 200 amp service) or larger feed conductors.
 

Last edited by AllanJ; 03-26-14 at 09:19 AM.
  #29  
Old 03-26-14, 09:04 AM
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My understanding is that I could use a cadweld or compression splice but the cost of either would probably be the same as buying new #4 solid copper and re-running it from the old ground rod to the new one, and I wouldn't have to hire someone to come out and do it. Since contacting the electrician I last hired to come out and install the ground rods, they have not responded to any of my multiple requests asking about the disconnection of the existing CEE, so I'd really prefer to just do it myself and know it's being done right.

The old GEC that is encased in the concrete is #4 stranded as best I can tell (I have 200 amp service). That is about 6 in. coming out of the concrete footer and is clamped to the old ground rod. The GEC from the old ground rod back to the meter pan (a separate #4 stranded) is run under the stucco up the side of the house into the attic and that is severed (partially) about an inch outside the stucco, I was able to split-bolt together the severed parts to keep it intact while waiting for the original repair, but now that GEC is no longer connected to the meter pan as it was disconnected by the electricians in favor of a new GEC to the (2) new ground rods.
 
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Old 03-26-14, 07:46 PM
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Here's another creative question regarding the CEE:

I read this online tonight:
The minimum requirements for a UFER ground, as outlined in the NEC, Article 250, is a minimum of 20' of bare copper wire, not smaller than #4, encased by at least 2" of concrete and located near the bottom of a concrete foundation footing that is in direct contact with the earth.

Given this, can I simply create a new CEE by running 20 ft of #4 wire in a 20 foot trench underground next to my house that I have poured several inches of concrete, and then clamp the wire to the existing ground rod? Or is there a requirement that it must be the same footing/foundation under the actual structure being protected by the grounding system?
 

Last edited by swbrains; 03-26-14 at 08:53 PM.
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Old 03-26-14, 11:34 PM
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Something else I just thought of... Could I run a #4 ground wire from the old ground rod (with the CEE connected to it) directly to the service panel which is just on the other side of the wall? Or do I have to run it to the new ground rods which are connected to the meter pan GEC?
 
  #32  
Old 03-27-14, 05:24 AM
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Yes you may run a grounding electrode conductor directly from a service panel (not a subpanel*) neutral to the concrete encased electrode itself, and if this run (possibly via a new bored hole through the foundation) is shorter, that is advantageous as well. It's also your choice to rabbit-ear* it to the CEE and then to the existing ground rod, or vice versa. Otherwise the path from CEE to panel needs approved splices.

If you create a new CEE (perhaps in a more convenient location) then you may cease use of a previously existing CEE. A CEE does not have to be a structural component of the building. There are some requirements in the NEC as to where it is situated. The grounding electrode system is intended to protect the electrical system and it protects the building incidentally.

Actually the basic GEC runs from a grounding electrode to the service neutral (e.g. main panel neutral bus). The rest of this thread (exothermic welds, multiple electrodes, etc.) discusses variations and embellishments.

* Like daisy chaining but the conductor is not broken and/or spliced at the first or other intermediate stop.

* If there is a master disconnect (breaker or switch) upstream of your primary breaker panel, for example at the meter pan then said breaker panel is technically a subpanel.
 

Last edited by AllanJ; 03-27-14 at 06:01 AM.
  #33  
Old 03-27-14, 06:45 AM
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Unfortunately, my main service panel does have an outside disconnect, so I guess it's really a subpanel (neutral and ground don't appear to be bonded in the panel anywhere).

"Like daisy chaining but the conductor is not broken and/or spliced at the first or other intermediate stop."
The original CEE wire was originally run out of the concrete footer (no exposed rebar) and clamped to the old ground rod, where it ended. A new (separate) wire was then clamped to the ground rod using a second clamp just above it and run from that ground rod to the meter pan.

So even in the original installation, there was a not a continuous run of the wire from the concrete to the rod to meter pan. Was the original installation therefore not code-compliant?
 
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