I have a friend who added an addtion to his house (this is attached). Previously his old meter was on the back of the house and connected to his panel just inside. We relocated the meter to the front of the house (per utility ). There we installed a new disconnect to feed over to his old panel (now sub panel), added new ground rods/wire to the disconnect , and ran 4 wire ser cable to his old panel (now a sub panel). The main disconnect is grounded where it should be (just outside and spaced per nec). Where the qustion is now, his new addtion has a ground rebar. Does this need to be attached to the new ground rods outside or is fine to be left alone since all the house wiring and wiring for the new addtion is coming from the subpanel which is grounded back to the disconnect? I cant seem to find the answer in the code. (this is in oregon)
Grounding rebar in addtion, is it needed?
- Thread starter hamster
- Start date
- Status
- Location
- Logan, Utah
Welcome to the forum.
If you are relocating and installing a new service and the new addition has rebar in the footing that qualifys as a concrete encased electrode, then IMHO you would be required to use the footing steel as a grounding electrode.
Chris
If you are relocating and installing a new service and the new addition has rebar in the footing that qualifys as a concrete encased electrode, then IMHO you would be required to use the footing steel as a grounding electrode.
Chris
Buck Parrish
Senior Member
- Location
- NC & IN
I thought it was either one of the two methods. Ufer ground or grd, rods.
- Location
- Logan, Utah
250.50 requires all grounding electrodes that are present must be used. So if the footing steel is present it must be used, it is not an option.
I agree that if a UFER ground is used you won't need to install the ground rods.
Chris
Jesse7623
Senior Member
- Location
- eastern Mass
Nope you have to do it,If its there you have to use it.
- Location
- Logan, Utah
I agree with you that it must be used but disagree with your use of the word "avaliable".
The 2005 NEC changed the wording in 250.50 from where "avaliable" to where "present". This change made it mandatory to use a conecrete encased electrode when it was present.
It used to be argued that if I didn't make a connection before the concrete was poured that the electrode was not avaliable and therefore didn't need to be used.
Chris
construct
Senior Member
- Location
- Branson, Missouri
I agree that it is mandatory on new construction. IMO the only way you are not required to use a reinforcing bar CEE is if it is smaller than 1/2" or the concrete is not in direct contact with earth. (i.e. vapor barrier that extends under and to the outside edge of the footing)
mikehughes8
Senior Member
- Location
- NC
I actually have a similiar question. A communication facility is installed on a concrete pad. As part of a lightining protection system we are installing a ground ring using ground treatment material, cadwelds, the whole nine yards. We have learned that the pad containes rebar. However, it is not accessible. Are we required to break up the concrete to expose the rebar, connect to it, then patch the concrete back up. Nobody knows how destructive this process will be. We have no idea as to the actual location of the rebar within the pad. Just educated guesses.
- Location
- Massachusetts
In my personal opinion if the work your doing is another project entirely from the pad you should not have to break it up.
If you did have to break it up you can have service locate the re-bars before you start hunting.
If you did have to break it up you can have service locate the re-bars before you start hunting.
construct
Senior Member
- Location
- Branson, Missouri
I don't feel that you are required to use it due to the exception in250.50. It states "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."
250.50 requires all present grounding electrodes to be bonded. In the new addition, you are installing an additional grounding electrode (concrete encased, assuming it meets the requirements of 250.52 (A)(3)). Although the building is existing, the addition is new construction.
You would not necessarily have to directly connect to the ground rods, but you do need to bond it to the rest of the grounding electrode system. This bond could be at the bonding connection with metal water pipe or at the grounding bus in the main service disconnecting means.
Just some more food for thought.
You would not necessarily have to directly connect to the ground rods, but you do need to bond it to the rest of the grounding electrode system. This bond could be at the bonding connection with metal water pipe or at the grounding bus in the main service disconnecting means.
Just some more food for thought.
Concrete in rebar
Concrete in rebar
In the case of the rebar in the concrete, it would seem if the requirements for the lightning protection system or ground system are to use the rebar and nothing else is available, then the matter of getting into the concrete is essential. If the area is dry or there is very little moisture for instance, the concrete with its' mositure would be the most likely place for the best ground. Not knowing where you are located, that might be the best option, of course not knowing the conditions.
I install comm centers all over the world, Mid East, Europe, Alasks and Southwest Asia and it works very well in these environments. The client actually prefers this method since there is almost a 100% success rate in getting the ground measurements within their specifications. The concrete repair is small in the scope of things. Hope this helps!
Concrete in rebar
In the case of the rebar in the concrete, it would seem if the requirements for the lightning protection system or ground system are to use the rebar and nothing else is available, then the matter of getting into the concrete is essential. If the area is dry or there is very little moisture for instance, the concrete with its' mositure would be the most likely place for the best ground. Not knowing where you are located, that might be the best option, of course not knowing the conditions.
I install comm centers all over the world, Mid East, Europe, Alasks and Southwest Asia and it works very well in these environments. The client actually prefers this method since there is almost a 100% success rate in getting the ground measurements within their specifications. The concrete repair is small in the scope of things. Hope this helps!
petersonra
Senior Member
- Location
- Northern illinois
- Occupation
- engineer
I would suggest you read very carefully what the code defines as a CEE.
You may come to the conclusion that the pad does not qualify as a CEE.
Cavie
Senior Member
- Location
- SW Florida
The vapor barrier does go to the edge of the footer BUT it does not go up the sides. Therefore you have at least 12/18" of concrete in direct contact with the earth. If for some reason you have no rebar, than you must install at least 20' of copper wire or rebar. Live with it.
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