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Posted By: gfretwell Mass Ufer rule - 11/18/05 07:20 PM
We have been boring the HIs with this for a few days, I decided to bring it over here.


I understand the electrical inspector is now required to inspect the rebar used for a concrete encased electrode. The connection can be made outside the concrete if a piece of rebar is exposed for that purpose. Will the electrician be responsible for installing the piece of rebar you connect to? If not, what is his function here?
Does he just tie a piece of copper wire on the bar to show he was there?
Who provides that piece of rebar if the steel worker is not installing it?


This is the way it is done here and the first time the EC is involved is when he puts the acorn on in the last frame.
[Linked Image from members.aol.com]

[This message has been edited by gfretwell (edited 11-18-2005).]
Posted By: George Little Re: Mass Ufer rule - 11/18/05 09:16 PM
Greg- Is that acorn suitable for re-bar? Some of them are and some of them are not. Maybe the inspector should be looking at it and checking on what type of conector they are using?
Posted By: gfretwell Re: Mass Ufer rule - 11/18/05 09:45 PM
George, I know that is a question that gets batted around occasionally but the short answer is, if it is the bronze clamp it is accepted.
Posted By: iwire Re: Mass Ufer rule - 11/18/05 09:49 PM
Some backround

Quote
MASSACHUSETTS ELECTRICAL CODE

Reinforcing Steel Electrodes

This change NEC (250.50) will dramatically change many aspects of trade sequencing, with severe consequences for any builder who fails to comply with the new rule. The 13 paragraphs that follow are adapted from letters made available to all licensed construction supervisors and building commissioners in Massachusetts.

A forthcoming change in the Massachusetts Electrical Code will, in many cases, dramatically change the way general contractors sequence the order of trades with respect to electrical work in particular. We believe that timely communication to this effect is crucial to the orderly completion of any work that will involve the placement of reinforcing steel in a concrete footing.

The 2005 NEC as adopted in July of 2004 by the National Fire Protection Association now requires that all qualifying concrete-encased grounding electrodes be connected to the grounding system for the building, unless the building is an already existing structure. A qualifying concrete-encased, reinforcing-steel electrode is

At least ½-in. in diameter (corresponding to a No. 4 bar, or larger); At least 20 ft in length (this measurement includes multiple pieces of steel if they are tied together); and Placed “within and near the bottom of a concrete foundation or footing that is in direct contact with the earth.” Not encapsulated in nonconductive coatings for corrosion resistance, such as epoxy.

This means, in turn, that for new construction, a connection must be made to such steel electrodes (where they exist) using a 4 AWG or larger copper grounding electrode conductor, with the other end of the wire arranged to leave the concrete at some convenient point.

The means for connection must be listed by a qualified testing laboratory (such as UL) both with respect to suitability for embedment in the concrete as well as for use with reinforcing steel.

Many electricians use wire long enough to reach from the foundation to the intended electrical service location, avoiding the need for a subsequent connection. Another approach involves bringing a segment of reinforcing steel out of the pour that is tightly tied to the segment(s) making up the qualified electrode.

The electrical connections are covered under MGL Chapter 141 and Chapter 143 Section 3L. Therefore the connection to the electrode must be done by a licensed electrician, which need not be the same person or firm responsible for the other work in the building.

Further, this work, including verification of the suitability of the tie wiring on the components of the electrode, must be inspected by a municipal Inspector of Wires prior to the completion of the concrete pour. If this process is not followed, the consequences could be severe, potentially resulting in a requirement to dismantle and rebuild the foundation.

This provision of the 2005 National Electrical Code is not being amended in Massachusetts. It, along with all other provisions of the 2005 Massachusetts Electrical Code, will apply to all electrical work in Massachusetts for which an electrical permit issues on or after January 1, 2005. We hope that you will assist us in making a smooth transition to the new requirement.

You may want to consider establishing a relationship with a licensed electrical contractor well in advance, at least with respect to being available to apply for the required electrical permits and having the required stock and personnel available so your construction schedules are not impeded.

Please note that this is not a requirement to install a concrete-encased electrode at any building (although it is always permitted). This is a requirement to connect to such an electrode if it will exist because of engineering design.

This work qualifies under Rule 10 of the Massachusetts Electrical Code for inspection within 24 hours of notice (weekends and holidays excluded) to the municipal Inspector of Wires, so construction should not be delayed for that reason. In fact, if the inspection does not take place within this time, the concrete pour can proceed without the completion of the inspection.

In a nutshell, IF THERE WILL BE REINFORCING STEEL IN THE FOOTING OR BOTTOM OF THE FOUNDATION IN ANY BUILDING you erect after the new year, then THERE MUST BE AN ELECTRICAL CONNECTION MADE (or arranged for if the steel will extend out of the concrete) AND AN ELECTRICAL INSPECTION PERFORMED PRIOR TO THE CONCRETE POUR.

Concrete-encased electrodes have a long history (over a half-century) of superior performance with respect to creating an effective ground reference. In New England soils, they are far superior to the any likely alternative, particularly with the increasing use of nonmetallic water piping systems. This change is squarely in the interest of public safety, so we want to do what we can to make its implementation as smooth as possible.
Posted By: gfretwell Re: Mass Ufer rule - 12/01/05 06:08 AM
I asked around a little about what folks thought would happen if some other sparky showed up to set his panel and the 4ga GEC was missing.
Several alternate grounding methods were suggested but then I told them about the Mass law requiring the sparky to dig out some steel in the footer (probably on his dime).
The unanamous answer, he would stuff a piece of wire in the wall and swear that was the same wire the inspector signed off if he thought he could get away with it. Of course everyone said they would always do the right thing themselves. [Linked Image]
Posted By: iwire Re: Mass Ufer rule - 12/01/05 10:57 AM
Greg code rules have always been written that rely on the character of the installer to obey.

Many things could be 'faked' to pass an inspection.

You really have an issue with this MA rule. [Linked Image]

As we do commercial work we may have copper sticking out of the footings in many locations and we do not seem to have any problem with them being stolen. The most common problem would be damage to the conductors from other trades.

As I told you before I do not know what the people building single family homes do for the uffer.
Posted By: Alan Nadon Re: Mass Ufer rule - 12/01/05 04:28 PM
I am Confused !!

I understand the requirements of the NEC.
However, the International Residential Code (IRC) does NOT allow rebar to be exposed outside of the foundation. Sec. R404.4.6.1 The only way I can see complaince is for the GEC to be connected to the rebar IN the foundation and the copper brought out of the concrete.

Is the chase in the photo filled with concrete after the wire is connected ??

We have not done this before and want to learn how it is done.

If i understand this would be similar to swimming pool grid bonding, only it is used to to ground not bond.
Alan--
Posted By: gfretwell Re: Mass Ufer rule - 12/01/05 04:40 PM
I am just confused as to why simply exposing a piece of rebar is not the best solution for the Ufer.
I agree damage from other trades is the biggest danger for the wire sticking out but a lot happens in a dwelling between footer and the TUG.
Posted By: Alan Nadon Re: Mass Ufer rule - 12/01/05 09:02 PM
I'm just an electrical inspector.
From what I understand of the wording in the Buyilding Code is that all rebar has to be covered by concrete.
I guess the general rule was written to prevent rebar from being placed too close to the surface where it would not provide structural support.
The other thing I heard is that exposed rebar acts like a wick allowing the bars to rust out inside the concrete, again affecting the strength.
Rust = Oxidation; from Oxygen not water as I always thought.
Before I make people do it I want to know how to do it correctly without causing problems for the other trades.
Alan--
Posted By: sandsnow Re: Mass Ufer rule - 12/06/05 04:27 PM
As long as the rebar is in a protected location such as inside a wall we will accept it. Rebar exposed to the weather is not acceptable. It will rust away because it's not gavanized and will transmit moisture to the rest of the rebar.
Some struct. engineers are hyper-concerned about the moisture intrusuin problem. They will not let the the copper UFER be tied to the structural rebar.
Posted By: gfretwell Re: Mass Ufer rule - 12/06/05 05:30 PM
One of the compromises I have seen tossed around is that they pour the "green" cell solid after the TUG inspection.
Posted By: iwire Re: Mass Ufer rule - 12/06/05 08:09 PM
Quote
Some struct. engineers are hyper-concerned about the moisture intrusuin problem. They will not let the the copper UFER be tied to the structural rebar.

I was not aware the was a choice available.

Quote
250.50 Grounding Electrode System.
If available on the premises at each building or structure served, each item in 250.52(A)(1) through (A)(6) shall be bonded together to form the grounding electrode system.

If the rebar is there we must tie into it.
Posted By: boggerbutt2454 Re: Mass Ufer rule - 12/06/05 11:06 PM
The first time I ran into the uffer ground was in sunny Las Vegas in the mid 1980's and we were required then to put the copper wire in the footer and tie it to the rebar and it was inspected and signed off by the same inspector that preformed the footing inspection. As I recall the building inspector did that. I'm not sure but I seem to remember them saying that they had to go and take a class so they would be qualified to inspect the grounding.
If we missed getting the uffer in or some low life cut it off, we had to dig a 2'x2'x2' hole, drive 4 stakes and coil 20 feet of cooper, and tie it to the stakes and pour it full of concrete. When this happened then we called the electrical inspector to inspected. All in all we didn't have that much problem with wire damage or thievery as we would sleeve it with PVC. When we got ready to tie it in to the service we just cut the PVC at the slab of bottom plate and put a little bit of pour stone in to seal up the PVC.
Since moving back east in the early 90's I have yet to see anyone use a uffer ground. The fact is I was suprised by how few of the electrical contractors here had ever heard of it.
Posted By: sandsnow Re: Mass Ufer rule - 12/07/05 12:26 AM
We had a choice until about 4 months ago, when we went on the 2002 NEC.

I've yet to run into these types of engineers since se've been on the 2002.
Posted By: Alan Nadon Re: Mass Ufer rule - 12/07/05 12:50 AM
Iwire,
I also thought the rebar must be connected. After the umpteenth time of reading about the concrete encased electrode IF 20 feet of #4 bare is used in the footer it becomes the concrete encased electrode and connection to the rebar is NOT required.
As an inspector I need to know all about this when we start making it mandatory.
Alan--
Posted By: resqcapt19 Re: Mass Ufer rule - 12/07/05 12:16 PM
Alan,
Quote
After the umpteenth time of reading about the concrete encased electrode IF 20 feet of #4 bare is used in the footer it becomes the concrete encased electrode and connection to the rebar is NOT required.
The installation of the copper does not make the rebar go away. The code section requires the rebar to be used as a grounding electrode if it is there. If both are there they both must be used.
Don
Posted By: Alan Nadon Re: Mass Ufer rule - 12/07/05 04:13 PM
I'm still tending to the idea that a concrete encased electrode is either the rebar or the 20 foot of #4.
If the rebar is there then A concrete encased electrode exist and must be used however the Code description of a concrete encased electrode from the beginning (250.52(A)(3) to the second comma first gives the location, from there to the next comma describes the rebar, then the word OR is used and the copper wire is described.
Unlike a swimming pool where the goal is to bond all the parts this is grounding so I believe that either the rebar OR the #4 wire achieves that goal.
Connecting the rebar to 20 feet of #4 wire will not substantially reduce the resistance to ground of the encased electrode.
[Ufer achieved >5 ohms in the desert. The difference between 5 & 2 1/2 ohms is negligable.]
250.50 requires all the listed electrodes to be bonded but, if the wire is the encased electrode and the rod is sealed in the cement then I would see no reason to bond the wire to the rerod.
I doubt if the reduction in resistance would be of as much benefit as not causing a problem for the structural integrity of the foundation.
Does anybody agree ?
Alan--
Posted By: walrus Re: Mass Ufer rule - 12/07/05 04:46 PM
Does this apply to slabs on grade??(contact with the earth?) and do you still have to drive 2 ground rods??
Posted By: gfretwell Re: Mass Ufer rule - 12/07/05 05:16 PM
I can't speak for folks north of the 25th parallel but here in Florida a "slab on grade" will still have a footer poured as part of the slab. They ring the slab with a 12" x 8" "bell" footer. This has 2 #5 rebar in it. That gets tied to the dowel rods in the block cores you see in the top picture.
They put VisQueen under the slab portion but not under the footer portion.

As for the pool, you MUST attach to the pool steel. If you don't have steel or the steel is epoxy encapsulated 2005 code requires you to duplicate the steel with a 12x12 copper mesh. I think the same principle applies to footer steel.
Posted By: earlydean Re: Mass Ufer rule - 12/08/05 12:21 AM
"680.26(C) The equipotential common bonding grid shall extend under paved walking surfaces for 1 m (3 ft) horizontally beyond the inside walls of the pool..." This sounds to me like only under the paved walkway around the pool.
Posted By: gfretwell Re: Mass Ufer rule - 12/08/05 02:41 AM
Look at 680.26(B)(1)
Posted By: resqcapt19 Re: Mass Ufer rule - 12/08/05 03:31 AM
Quote
and do you still have to drive 2 ground rods??
No ground rods are required if you use a concrete encased electrode.
Don
Posted By: yaktx Re: Mass Ufer rule - 12/08/05 03:58 AM
Several years ago, my area went to concrete-encased electrodes on all new construction. I don't know how it is usually done, since I have rarely been involved in that phase of the job and now I generally don't do new construction at all.

For the past year, I have been using a type of concrete-encased electrode that has been recommended to me by several local AHJs, and that is due to be adopted as the standard for existing construction.

I dig a hole 30" deep and 24" diameter, and place 25' of coiled bare #2 Cu at the bottom. Add a bag of Quikrete, mix in water, then backfill. One AHJ advised me to leave the bag on the ground nearby, with a hose available, so he could pour it in himself after inspection.

I started using this method on the west side of town, where driving ground rods is frequently close to impossible. Word is ground rods will soon be eliminated altogether.
Posted By: gfretwell Re: Mass Ufer rule - 12/08/05 05:13 AM
You would have a hard time convincing any AHJ around here he was mixing your concrete.
Posted By: George Little Re: Mass Ufer rule - 12/09/05 10:28 AM
Alan- I agree with you. We are still on the '02 code here in Michigan so we haven't been pushing the concrete encased electrode yet but I would agree with you that all the rods in all the concrete are not automatically electrodes. If that's the case, we have a major problem on our hands.
Posted By: cpal Re: Mass Ufer rule - 12/09/05 12:47 PM
This is not a Mass rule the use of the concrete encased electrode is a NEC requirement that is not amended by the Mass Board of Fire Prevention.

The letter that I-wire posted was circulated by the chair of the Mass Code Advisory Committee in an effort to coordinate the inspectional process between the building commissioners and the inspectors of wires.

As was mentioned if the rod is not in the pour this electrode is not required to be established although it may!
Posted By: harold endean Re: Mass Ufer rule - 12/11/05 10:51 PM
Greg,

Here in NJ the building inspector checks for the footing ground and it is only required on new buildings. Also as someone else said, the whole piece of rebar has to be encased otherwise it isn't rebar and the BI will fail you. Also in this state you do not need ground rods if you have a footing ground but some AHJ's will still ask for it, even though they are not suppose to.
Posted By: Alan Nadon Re: Mass Ufer rule - 12/13/05 12:47 AM
Should the electrical industry quit messing around and just require 20 foot of # 4 and not rely on other trades to do our grounding for us ?
We had this whole agruement in the 1920's with plumbers about using their water pipes.
I suggest that we just put in the wire and not connect it to any thing except the earth.

Alan--
Posted By: gfretwell Re: Mass Ufer rule - 12/13/05 01:34 AM
Alan, I would say you want the rebar because a couple hundred feet of rebar is a lot better than 20 feet of copper. It makes the whole footer a ground electrode instead of just 20 feet. If we really thought concrete alone was a good conductor we would just be using a 20' wire in a pool.

BTW we don't seem to mind steel workers building our electrode when it is building steel

[This message has been edited by gfretwell (edited 12-12-2005).]

[This message has been edited by gfretwell (edited 12-12-2005).]
Posted By: tdhorne Re: Mass Ufer rule - 01/03/06 02:32 AM
I showed up on one job to do the temporary service and found the rebar in place and the concrete guys just waiting for the mud to be delivered. I asked them to stub up a piece of well tied rebar out of the footer and coat the last several feet of it with the foundation water proofing cement they had on site. They acted like I was crazy but they did it. It measured a lot lower than the thirty feet of number two that was used on the house next door. I have read somewhere that the steel does better in the footer than the bare copper does. Is galvanized rebar readily available? Will it help with the corrosion problem on the stub up. Galvanized ground rods are installed all the time so I presume that the galvaneal coating is reasonably conductive.
--
Tom Horne

"This alternating current stuff is just a fad. It is much too dangerous for general use." Thomas Alva Edison
Posted By: Alan Nadon Re: Mass Ufer rule - 01/06/06 01:52 PM
We are starting to inspect for the Ufer ground. 250.52
The Code requires 1/2 inch rebar. If the contractor uses 3/8 inch rebar do we ignore it, and go back to just using a ground rod and water plus Building steel when available.
Some contractors around here just float pieces of rebar into the concrete and don't tie wire them together or have them raised up on chairs.
Alan--
Posted By: dlhoule Re: Mass Ufer rule - 01/06/06 04:57 PM
Alan,

Were you actually around in the 20's? I can remember things from when I started out, and have heard about others. Have you ever tried to update an older home originally wired with all rigid conduit?
Posted By: gfretwell Re: Mass Ufer rule - 01/06/06 07:24 PM
I suppose there are places where rebar in the footer is not required but it is one of the major inspections in the Florida Building Code. It has to be #5 or larger, tied and up on chairs.
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