code
- Thread starter tim
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bphgravity
Senior Member
- Location
- Florida
Re: code
I feel the newer editions of the NEC can be used as a guideline for the intent of older versions. In most cases, changes are made to add clarity to the NEC or to remove confusing terminology.
In my area, I was one of the first contractors to use in-use covers even though the state had not yet adopted the 2002 NEC. At the same time, I am in no rush to start using concrete-encased electrodes, even if it is "present".
If added safety can be provided to the customer without a prohibitive cost to the customer I will use the newer code.
I feel the newer editions of the NEC can be used as a guideline for the intent of older versions. In most cases, changes are made to add clarity to the NEC or to remove confusing terminology.
In my area, I was one of the first contractors to use in-use covers even though the state had not yet adopted the 2002 NEC. At the same time, I am in no rush to start using concrete-encased electrodes, even if it is "present".
If added safety can be provided to the customer without a prohibitive cost to the customer I will use the newer code.
pierre
Senior Member
- Location
- Westchester County, New York
Re: code
Bryan
If you were to use the concrete encased electrode, you would not need to drive ground rods - even though in Florida it is a cinch to drive rods
Bryan
If you were to use the concrete encased electrode, you would not need to drive ground rods - even though in Florida it is a cinch to drive rods
charlie
Senior Member
- Location
- Indianapolis
Re: code
I think most of us are answering question based on the 2002 Code. The 2005 is generally adopted in the spring in most areas. Some jurisdictions have already adopted the 2005 and there are some that are still working from the 1990. If you are asking a question for a different cycle, put that into the question or you will probably get a 2002 answer.
I think most of us are answering question based on the 2002 Code. The 2005 is generally adopted in the spring in most areas. Some jurisdictions have already adopted the 2005 and there are some that are still working from the 1990. If you are asking a question for a different cycle, put that into the question or you will probably get a 2002 answer.
allenwayne
Senior Member
Re: code
We are still under the 2002 code.But one county has adopted addendums that well are a pain in the B_ _ t,Like all receptacles in a garage even dedicated will be GFCI protected if the appliance/unit is not there for final inspection.HO`R pays for a freezer circuit in garage but hasn`t closed yet so his brand new freezer is not there for final.
We have to install a gfci device that is sure to trip in the next year of warranty 200 lb freezer with how much meat must be moved to push a STUPID button
We are still under the 2002 code.But one county has adopted addendums that well are a pain in the B_ _ t,Like all receptacles in a garage even dedicated will be GFCI protected if the appliance/unit is not there for final inspection.HO`R pays for a freezer circuit in garage but hasn`t closed yet so his brand new freezer is not there for final.
We have to install a gfci device that is sure to trip in the next year of warranty
200 lb freezer with how much meat must be moved to push a STUPID buttonbphgravity
Senior Member
- Location
- Florida
Re: code
Here's my problem with grounding: I don't understand it.
I have read pages and pages of history, research, and opinion on the significance of grounding electrode systems, and nothing is definitive and absolute.
All data suggests the concrete-encased electrode provides the lowest resistance to ground of all the permitted electrodes. The problem is, no data indicates why this is important. Data has shown that a concrete encased electrode involved in a lightning strike may instantly heat the moisture under and in the concrete slab to steam which will then crack and damage the slab as it exapands 100 times its orignial volume.
Utility and water companies are becomming increasingly concerned that stray voltages are a resulted of community metal water pipes being used as electrodes for buildings and structures, yet nonone can conclusively prove anyone is really being hurt from this.
So basically, the jury is still out for me on whether or not the grounding electrode system is all what it is cracked up to be. Until I understand it better or read evidence of what we are really accomplishing by connecting to various components in contact with Earth, i am not going to put to much thought or effort in the design of the grounding electrode systems I install.
If a concrete-encased electrode is "available", i will use it. I am still going to supplement it with a driven rod. So, I might as well just drive a couple of rods and not worry with the building structure at all.
Here's my problem with grounding: I don't understand it.
I have read pages and pages of history, research, and opinion on the significance of grounding electrode systems, and nothing is definitive and absolute.
All data suggests the concrete-encased electrode provides the lowest resistance to ground of all the permitted electrodes. The problem is, no data indicates why this is important. Data has shown that a concrete encased electrode involved in a lightning strike may instantly heat the moisture under and in the concrete slab to steam which will then crack and damage the slab as it exapands 100 times its orignial volume.
Utility and water companies are becomming increasingly concerned that stray voltages are a resulted of community metal water pipes being used as electrodes for buildings and structures, yet nonone can conclusively prove anyone is really being hurt from this.
So basically, the jury is still out for me on whether or not the grounding electrode system is all what it is cracked up to be. Until I understand it better or read evidence of what we are really accomplishing by connecting to various components in contact with Earth, i am not going to put to much thought or effort in the design of the grounding electrode systems I install.
If a concrete-encased electrode is "available", i will use it. I am still going to supplement it with a driven rod. So, I might as well just drive a couple of rods and not worry with the building structure at all.
physis
Senior Member
Re: code
I can't say I disagree with what you point out Bryan.
But I think the more important role being played buy the electrode system is keeping the planet near the building at a safe voltage relative to all the metal and equipment in the building. And for that, grounding the foundation is fabulous.
I'd expect that without grounding systems there would be a lot more people getting shocked from goofy stray voltages that can come all kinds of things. I think it's good to keep earth at a relative 0v. potential.
Lightning's going to break and damage stuff no matter what you do, mostly.
I can't say I disagree with what you point out Bryan.
But I think the more important role being played buy the electrode system is keeping the planet near the building at a safe voltage relative to all the metal and equipment in the building. And for that, grounding the foundation is fabulous.
I'd expect that without grounding systems there would be a lot more people getting shocked from goofy stray voltages that can come all kinds of things. I think it's good to keep earth at a relative 0v. potential.
Lightning's going to break and damage stuff no matter what you do, mostly.
bphgravity
Senior Member
- Location
- Florida
Re: code
Roger is not joking. This is a true story. I started a ground rod by hand and got it about 3-4 feet in. At that point, I stuck it one and only one time with a 3 pound hammer. It sunk so far into the ground that I actually had to dig down nearly a foot to find where it finally stopped.
I have actually heard of a few electricians that drove an 8 foot rod and sprung an artesian well. In most areas around here, once you dig around 4 feet down you hit water.
Roger is not joking. This is a true story. I started a ground rod by hand and got it about 3-4 feet in. At that point, I stuck it one and only one time with a 3 pound hammer. It sunk so far into the ground that I actually had to dig down nearly a foot to find where it finally stopped.
I have actually heard of a few electricians that drove an 8 foot rod and sprung an artesian well. In most areas around here, once you dig around 4 feet down you hit water.
pierre
Senior Member
- Location
- Westchester County, New York
Re: code
Bryan
I also have read alot and like you I have to try and come up with my own conclusions - which I do ), and could be a real workout if not using a power driver.
Bryan
I also have read alot and like you I have to try and come up with my own conclusions - which I do
), and could be a real workout if not using a power driver.allenwayne
Senior Member
Re: code
I have seen over the years the result of lightning strikes ranging from blown up electronics to roof top hits that have caused fires.There is one type that I have seen quite a few times,I like to call it residual lightning strikes.
From time to time I have found upon opening panels that all the bare copper and exposed copper of the grounded conductors to have changed in color to an almost black appearence.I have found this in homes that have an energizrd service and also in homes that were getting a final inspection.Run your finger across the wire and there is a residue but it doesn`t remove the black.Checking the ground wire it also has this same discoloration.Surge arrestor has never been hit.In some of these finds the white insulation has also changed color to an almost beige color.
Checking the first points in the home wiring from these homeruns there is no discoloration You would think that it would involve the rest of the wiring but as I have found it has always stayed within the meter/panel area
I have seen over the years the result of lightning strikes ranging from blown up electronics to roof top hits that have caused fires.There is one type that I have seen quite a few times,I like to call it residual lightning strikes.
From time to time I have found upon opening panels that all the bare copper and exposed copper of the grounded conductors to have changed in color to an almost black appearence.I have found this in homes that have an energizrd service and also in homes that were getting a final inspection.Run your finger across the wire and there is a residue but it doesn`t remove the black.Checking the ground wire it also has this same discoloration.Surge arrestor has never been hit.In some of these finds the white insulation has also changed color to an almost beige color.
Checking the first points in the home wiring from these homeruns there is no discoloration
You would think that it would involve the rest of the wiring but as I have found it has always stayed within the meter/panel areajimwalker
Senior Member
- Location
- TAMPA FLORIDA
Re: code
Not all places in Florida are that easy to drive rods.I did 40 town houses near down town Tampa that even with atachment for chipping hammer took 20 to 30 minutes each.Will say that most can go in with 3 lb hammer in a few minutes.Have yet to push one in by hand.
Not all places in Florida are that easy to drive rods.I did 40 town houses near down town Tampa that even with atachment for chipping hammer took 20 to 30 minutes each.Will say that most can go in with 3 lb hammer in a few minutes.Have yet to push one in by hand.
charlie
Senior Member
- Location
- Indianapolis
Re: code
Jim, maybe if you were stronger . . .
Jim, maybe if you were stronger . . .
jimwalker
Senior Member
- Location
- TAMPA FLORIDA
Re: code
LOLperhaps i use wrong end of hammer
[ March 14, 2005, 05:43 AM: Message edited by: jimwalker ]
LOL
perhaps i use wrong end of hammer[ March 14, 2005, 05:43 AM: Message edited by: jimwalker ]
- Location
- Illinois
- Occupation
- retired electrician
Re: code
Sam,
Don
Sam,
That doesn't really work that way. The earth is not a good enough conductor to permit the grounding electrode to change the potential of the earth. Studies have shown that 80% to 90% of voltage impressed on an electrode is dropped within a few feet of the electrode.
Don
al hildenbrand
Senior Member
- Location
- Minnesota
- Occupation
- Electrical Contractor, Electrical Consultant, Electrical Engineer
Re: code
Don,
I think Sam has a good point, from the perspective of the string or mesh of interconnected connections of the distribution grounded conductor to earth.
Perhaps the simplest to visualize is a single phase two wire transmission line with one wire grounded periodically along the (hypothetical) 20 mile line. Let's place the transmission line in the open country away from other effects.
Over this distance, the earth will be subject to the gathering of electrostatic charges that, ultimately, can escalate to lightning levels. Up to a point, the charge accumulation in the immediate vicinity of the earth connections of the grounded wire, will be shorted through the "bleed resistance" that the earth connection and wire represent.
Don,
I think Sam has a good point, from the perspective of the string or mesh of interconnected connections of the distribution grounded conductor to earth.
Perhaps the simplest to visualize is a single phase two wire transmission line with one wire grounded periodically along the (hypothetical) 20 mile line. Let's place the transmission line in the open country away from other effects.
Over this distance, the earth will be subject to the gathering of electrostatic charges that, ultimately, can escalate to lightning levels. Up to a point, the charge accumulation in the immediate vicinity of the earth connections of the grounded wire, will be shorted through the "bleed resistance" that the earth connection and wire represent.
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