ᐅ Forgot to install the foundation grounding system – any advice?
Created on: 5 Mar 2016 18:48
K
Kerstin2Hello everyone, in our excitement we forgot about the foundation grounding. We were talking about the foundation grounding the whole time, but now the foundations are finished and the grounding is not installed!
There will be a slab under the garage, and under the slab of the house, there will be 10cm (4 inches) of XPS insulation.
What would you suggest we do?
There will be a slab under the garage, and under the slab of the house, there will be 10cm (4 inches) of XPS insulation.
What would you suggest we do?
Kerstin2 schrieb:
What would be your approach? There is plenty of free downloadable secondary literature available on this topic, such as the DEHN lightning planner, the VdB lightning protection installation manual, Kleiske Info, and also slides from me, which everyone can consult even without a VDE selection subscription or DIN 18014, to learn about who is authorized to install foundation grounding.
If the frost skirt does not have full perimeter insulation, a foundation grounding conductor would have been sufficient. Since it is now too late for that, the only option is to install a protective conductor in the insulated slab and a code-compliant stainless steel ring earth electrode (V4A) in the natural ground. A vertical earth rod is cheaper but not an equivalent substitute for the ring earth electrode.
Details such as mesh sizes and other specifications are covered comprehensively in the mentioned publications.
L
Landschafter118 Jun 2016 14:46Hello everyone,
We started building our house in March of this year. Except for the earthworks, everything was contracted to a general contractor. He also forgot the foundation earth electrode / functional equipotential bonding, or rather, his subcontractor forgot it... There are expert reports from both sides regarding the issue that occurred.
The general contractor’s expert assured me that everything was fine... Since I was skeptical, I sent it to another expert, who was mentioned above. The first thing that caught his attention was that the general contractor’s expert had used the 2007 version of the DIN standard, including all tolerances and measurement values – also, the measuring instrument was not approved by the VDE (German Association for Electrical, Electronic & Information Technologies)...
The general contractor’s expert tried to compensate for the missing foundation earth electrode and functional equipotential bonding by installing a ring earth conductor around the house and connecting it to the reinforcement of the foundation slab at four points. The ring earth conductor itself is embedded in the soil at a maximum depth of 60cm (24 inches), sometimes less than 20cm (8 inches), and even partly in gravel / crushed stone. It also does not surround the entire structure but was pushed underneath the foundation slab at one point (width at that area 2.2m (7 feet 3 inches)). Furthermore, the mesh spacing of 20 by 20m (65 by 65 feet) was not maintained.
We presented all this again to the general contractor and his expert, but both still claim that "everything is free of defects and does not pose a threat to health or safety."
My expert said that retrofitting the functional equipotential bonding according to the DIN standard is practically impossible or would involve enormous effort. He also views the ring earth conductor critically since the reinforced mesh underneath the foundation slab would also be difficult to install.
We started building our house in March of this year. Except for the earthworks, everything was contracted to a general contractor. He also forgot the foundation earth electrode / functional equipotential bonding, or rather, his subcontractor forgot it... There are expert reports from both sides regarding the issue that occurred.
The general contractor’s expert assured me that everything was fine... Since I was skeptical, I sent it to another expert, who was mentioned above. The first thing that caught his attention was that the general contractor’s expert had used the 2007 version of the DIN standard, including all tolerances and measurement values – also, the measuring instrument was not approved by the VDE (German Association for Electrical, Electronic & Information Technologies)...
The general contractor’s expert tried to compensate for the missing foundation earth electrode and functional equipotential bonding by installing a ring earth conductor around the house and connecting it to the reinforcement of the foundation slab at four points. The ring earth conductor itself is embedded in the soil at a maximum depth of 60cm (24 inches), sometimes less than 20cm (8 inches), and even partly in gravel / crushed stone. It also does not surround the entire structure but was pushed underneath the foundation slab at one point (width at that area 2.2m (7 feet 3 inches)). Furthermore, the mesh spacing of 20 by 20m (65 by 65 feet) was not maintained.
We presented all this again to the general contractor and his expert, but both still claim that "everything is free of defects and does not pose a threat to health or safety."
My expert said that retrofitting the functional equipotential bonding according to the DIN standard is practically impossible or would involve enormous effort. He also views the ring earth conductor critically since the reinforced mesh underneath the foundation slab would also be difficult to install.
Just one more extreme example of the usual resistance to standards regarding DIN 18014.
For execution, the nominal values valid at the time of completion are decisive.
That earthing systems may only be installed by licensed electrical or lightning protection specialists according to NAV and must be documented before concreting is not a new requirement, contrary to the amendment announcements of DIN 18014:2014-03.
More significant is the change in the continuity resistance from 1 to 0.2 ohms and the minimum installation depth, see below.
This is an emergency solution but not a fully compliant substitute for a functional equipotential bonding conductor embedded in the base slab according to paragraph 5.7.2 Combined Equipotential Bonding System (CBN) of DIN 18014, which must be connected to the reinforcement every 2 m (6.5 feet). Even if this emergency solution was implemented, in my opinion there is still a justified claim for reduction.
Even if installed with standard-compliant mesh spacing, such ring earth conductors do not comply with the recognized rules of technology.
The frost-free minimum installation depth of ≥ 0.5 m (1.6 feet) according to the old DIN 18014:2007-09 was increased to ≥ 0.8 m (2.6 feet) in DIN 18014:2014-03 to align with the building standard DIN 1054 and may require greater depths depending on the region.
In cases of such fundamental errors, one can try to take an aggressive stance. A work is deemed flawless if it substantially complies with the recognized rules of technology (= standards), which is evidently not the case here in multiple respects.
Whether there is a danger to life or limb primarily depends on the earth resistivity. At what levels and during which seasons was it measured? Ring earth conductors installed fully contact with the soil generally show better results, and from my legal perspective, one is not required to accept compliance with worse but sufficient values.
The initial mistake could only have been corrected by demolition, which in my opinion would still have been proportionate in terms of effort as long as the basement level was not yet built. A ring earth conductor that does not fully encircle the building in contact with the soil can also be retrofitted to meet the nominal requirements. Excessive mesh sizes of 20 m x 20 m (66 by 66 feet) without, or 10 m x 10 m (33 by 33 feet) with lightning protection can be compensated by additional vertical earth electrodes.
Landschafter1 schrieb:
The first thing he noticed was that the client’s expert used the 2007 version of the DIN standard, including all tolerances and measurement values – and the measuring instrument was not even approved by the VDE ...
For execution, the nominal values valid at the time of completion are decisive.
That earthing systems may only be installed by licensed electrical or lightning protection specialists according to NAV and must be documented before concreting is not a new requirement, contrary to the amendment announcements of DIN 18014:2014-03.
More significant is the change in the continuity resistance from 1 to 0.2 ohms and the minimum installation depth, see below.
Landschafter1 schrieb:
The client’s expert tried to compensate for the missing foundation earth and functional equipotential bonding by installing a ring earth conductor around the house and connecting it to the reinforcement of the base slab at four points.
This is an emergency solution but not a fully compliant substitute for a functional equipotential bonding conductor embedded in the base slab according to paragraph 5.7.2 Combined Equipotential Bonding System (CBN) of DIN 18014, which must be connected to the reinforcement every 2 m (6.5 feet). Even if this emergency solution was implemented, in my opinion there is still a justified claim for reduction.
Landschafter1 schrieb:
The ring earth conductor itself is buried at a maximum depth of 60 cm (24 inches), in some places less than 20 cm (8 inches), and even runs through gravel/scree. It also does not encompass the entire building but is routed under the base slab in one area (width of this section 2.2 m (7.2 feet)). The mesh spacing of 20 m by 20 m (66 by 66 feet) was not maintained either.
Even if installed with standard-compliant mesh spacing, such ring earth conductors do not comply with the recognized rules of technology.
The frost-free minimum installation depth of ≥ 0.5 m (1.6 feet) according to the old DIN 18014:2007-09 was increased to ≥ 0.8 m (2.6 feet) in DIN 18014:2014-03 to align with the building standard DIN 1054 and may require greater depths depending on the region.
Landschafter1 schrieb:
We submitted all of this again to the client and their expert, but both still insist “everything is flawless and poses no danger to life or limb”.
In cases of such fundamental errors, one can try to take an aggressive stance. A work is deemed flawless if it substantially complies with the recognized rules of technology (= standards), which is evidently not the case here in multiple respects.
Whether there is a danger to life or limb primarily depends on the earth resistivity. At what levels and during which seasons was it measured? Ring earth conductors installed fully contact with the soil generally show better results, and from my legal perspective, one is not required to accept compliance with worse but sufficient values.
Landschafter1 schrieb:
My expert said retrofitting the functional equipotential bonding according to the DIN is practically impossible or would involve huge effort. He is also critical of the ring earth conductor since the mesh under the base slab would be difficult to install.
The initial mistake could only have been corrected by demolition, which in my opinion would still have been proportionate in terms of effort as long as the basement level was not yet built. A ring earth conductor that does not fully encircle the building in contact with the soil can also be retrofitted to meet the nominal requirements. Excessive mesh sizes of 20 m x 20 m (66 by 66 feet) without, or 10 m x 10 m (33 by 33 feet) with lightning protection can be compensated by additional vertical earth electrodes.
Hats off to Roland’s expertise.
When building, I wished there were only such competent people on site.
Instead, I always had to educate myself and then specifically address issues.
Respect, dear Roland, for your knowledge and your attitude towards the subject/profession.
Best regards
Thorsten
When building, I wished there were only such competent people on site.
Instead, I always had to educate myself and then specifically address issues.
Respect, dear Roland, for your knowledge and your attitude towards the subject/profession.
Best regards
Thorsten
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