When do the steel beams within a residence require bondi
- Thread starter dabent
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jimwalker
Senior Member
- Location
- TAMPA FLORIDA
Re: When do the steel beams within a residence require bondi
in 22 years never
in 22 years never
ryan_618
Senior Member
- Location
- Salt Lake City, Utah
Re: When do the steel beams within a residence require bondi
When the criteria of 250.104(C) is met, which is probably very seldom
When the criteria of 250.104(C) is met, which is probably very seldom
dana1028
Senior Member
- Location
- San Francisco Bay area
Re: When do the steel beams within a residence require bondi
250.52(A)(2)- requires the metal frame of the bldg. to be used as part of the electrode system 'where effectively grounded'.
As Jim said, 'never' seen it in residential...this is because every steel beam I've ever encountered ( in residential)was an isolated structural member....i.e. not tied into other steel members that created the bldg. framework.
Where this (250.52A2) comes into play (usually) is in commercial/industrial bldgs. where the entire bldg. framework is steel (beams, columns, girders, etc.)...in this type of construction, often times the bolts that secure the columns into place (into huge concrete piers embedded into the monolithic concrete slab) have bonding conductors welded (or cad-welded)to the huge bolts and to the rebar within the slab....thus forming a huge electrode system.
In this scenario there would not likely be a Ufer made available to be part of the electode system ....you would then include the steel columns as part of the electrode system and bond the metal water piping to the bldg. steel. (in the bldgs. I have seen, there have been no ground rods installed and no Ufers made available....so you use the water piping and the bldg. steel).
Hope that wasn't too confusing
250.52(A)(2)- requires the metal frame of the bldg. to be used as part of the electrode system 'where effectively grounded'.
As Jim said, 'never' seen it in residential...this is because every steel beam I've ever encountered ( in residential)was an isolated structural member....i.e. not tied into other steel members that created the bldg. framework.
Where this (250.52A2) comes into play (usually) is in commercial/industrial bldgs. where the entire bldg. framework is steel (beams, columns, girders, etc.)...in this type of construction, often times the bolts that secure the columns into place (into huge concrete piers embedded into the monolithic concrete slab) have bonding conductors welded (or cad-welded)to the huge bolts and to the rebar within the slab....thus forming a huge electrode system.
In this scenario there would not likely be a Ufer made available to be part of the electode system ....you would then include the steel columns as part of the electrode system and bond the metal water piping to the bldg. steel. (in the bldgs. I have seen, there have been no ground rods installed and no Ufers made available....so you use the water piping and the bldg. steel).
Hope that wasn't too confusing
- Location
- Lockport, IL
- Occupation
- Semi-Retired Electrical Engineer
Re: When do the steel beams within a residence require bondi
Just out of curiosity, are you dealing with a real-world problem, or just an academic discussion?
Just out of curiosity, are you dealing with a real-world problem, or just an academic discussion?
sandsnow
Senior Member
- Location
- Southern California
Re: When do the steel beams within a residence require bondi
I've watched steel become more of a part of residential construction over years as building code reqm's change. The most I have seen is two columns and one beam conected together. They were not exposed as in 250-104(d) so did not require bonding. It was decided that the requirements of 250-50(b) were not met and it did not need to be bonded to the grounding electrode system.
We have found there is always have a footing available somewhere in a commercial bldg for the UFER and the engineer usually calls for one. i've seen some pretty extravagantly designed UFER systems. Such as two 50 foot lengths of 500kcmil each way in the footing.
I've watched steel become more of a part of residential construction over years as building code reqm's change. The most I have seen is two columns and one beam conected together. They were not exposed as in 250-104(d) so did not require bonding. It was decided that the requirements of 250-50(b) were not met and it did not need to be bonded to the grounding electrode system.
We have found there is always have a footing available somewhere in a commercial bldg for the UFER and the engineer usually calls for one. i've seen some pretty extravagantly designed UFER systems. Such as two 50 foot lengths of 500kcmil each way in the footing.
pierre
Senior Member
- Location
- Westchester County, New York
Re: When do the steel beams within a residence require bondi
How about if the steel is 'effectively' grounded, and one uses it for the purpose of 250.53(D)(2) instead of driving two ground rods.
The question that begs to be answered now is; what is effectively grounded?
Pierre
How about if the steel is 'effectively' grounded, and one uses it for the purpose of 250.53(D)(2) instead of driving two ground rods.
The question that begs to be answered now is; what is effectively grounded?
Pierre
websparky
Senior Member
- Location
- Cleveland, Ohio
Re: When do the steel beams within a residence require bondi
Pierre,
Building steel is never a grounding electrode.
Pierre,
Building steel is never a grounding electrode.
- Location
- Massachusetts
Re: When do the steel beams within a residence require bondi
it is one of the electrodes in the list.
Take a look at 250.52(A)(2)
it is one of the electrodes in the list.
websparky
Senior Member
- Location
- Cleveland, Ohio
Re: When do the steel beams within a residence require bondi
Piere, Bob and Derick,
Sorry!
I just wasn't paying attention!
Piere, Bob and Derick,
Sorry!
I just wasn't paying attention!
pierre
Senior Member
- Location
- Westchester County, New York
Re: When do the steel beams within a residence require bondi
Dave
There are a lot of new homes being built around here, and most of them are quite large - with steel throughout the basement. I have been telling the contractors to have the GC use a 'J' bolt in the pier, bonded to the rebar, that the lolly column is on and then I consider it 'effectively' grounded, using it as a supplemental grounding electrode. I personnally believe it is a better ground than any ground rod in our area.
Pierre
Dave
There are a lot of new homes being built around here, and most of them are quite large - with steel throughout the basement. I have been telling the contractors to have the GC use a 'J' bolt in the pier, bonded to the rebar, that the lolly column is on and then I consider it 'effectively' grounded, using it as a supplemental grounding electrode. I personnally believe it is a better ground than any ground rod in our area.
Pierre
- Location
- Massachusetts
Re: When do the steel beams within a residence require bondi
Pierre I do not see how you can tell them to do that, IMO you can only ask for that.
What code section gives you that power?
Bob
Pierre I do not see how you can tell them to do that, IMO you can only ask for that.
What code section gives you that power?
Bob
pierre
Senior Member
- Location
- Westchester County, New York
Re: When do the steel beams within a residence require bondi
Bob
You are right...I did not write that post correctly. What I meant is, I tell the EC that they can use the steel as the Supplemental ground, avoiding driving ground rods.
There are many areas here that it is very, very difficult to drive ground rods.
One day I will learn how to write in a more clear manner... until then thanks for keeping me on my toes. Remember, I was a contractor for years, and remember how difficult sometimes driving ground rods can be.
[ August 15, 2004, 12:06 PM: Message edited by: pierre ]
Bob
You are right...I did not write that post correctly. What I meant is, I tell the EC that they can use the steel as the Supplemental ground, avoiding driving ground rods.
There are many areas here that it is very, very difficult to drive ground rods.
One day I will learn how to write in a more clear manner... until then thanks for keeping me on my toes. Remember, I was a contractor for years, and remember how difficult sometimes driving ground rods can be.
[ August 15, 2004, 12:06 PM: Message edited by: pierre ]
- Location
- Massachusetts
Re: When do the steel beams within a residence require bondi
Pierre I doubt you need anyone to keep you on your toes.
I think your suggestion is an excellent one and I would do it that way if the opportunity presented itself.
Bob
Pierre I doubt you need anyone to keep you on your toes.
I think your suggestion is an excellent one and I would do it that way if the opportunity presented itself.
Bob
websparky
Senior Member
- Location
- Cleveland, Ohio
Re: When do the steel beams within a residence require bondi
Pierre,
In my area, the steel columns set on top of a concrete pad, usually 4-6 inches below the finished concrete floor. Some of the steel beams span from basement wall to basement wall with no columns. The ones with columns may offer some contact with the earth for grounding purposes but the earth under the basement would have to be some-what moist to be effective.
In either case, I would not consider the steel to be a good electrode. However, if one were to bond the steel......it wouldn't hurt anything. Does the steel need to be bonded? That would be a judgement call for the AHJ.
Pierre,
In my area, the steel columns set on top of a concrete pad, usually 4-6 inches below the finished concrete floor. Some of the steel beams span from basement wall to basement wall with no columns. The ones with columns may offer some contact with the earth for grounding purposes but the earth under the basement would have to be some-what moist to be effective.
In either case, I would not consider the steel to be a good electrode. However, if one were to bond the steel......it wouldn't hurt anything. Does the steel need to be bonded? That would be a judgement call for the AHJ.
jafro
Member
- Location
- Fort Saskatchewan, Alberta, Canada
Re: When do the steel beams within a residence require bondi
In Canada we would require the steel beam to be bonded if there was a possibility of it becoming energized. Possibility is if there are any nmd cables located in the proximity that could come in contact with the beam.
Jafro
In Canada we would require the steel beam to be bonded if there was a possibility of it becoming energized. Possibility is if there are any nmd cables located in the proximity that could come in contact with the beam.
Jafro
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