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.
[This message has been edited by gfretwell (edited 11-18-2005).]
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.
Bob Badger Construction & Maintenance Electrician Massachusetts
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.
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.
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.
Bob Badger Construction & Maintenance Electrician Massachusetts
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--
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.
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--
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.