ᐅ Equipotential bonding? Grounding ring or foundation grounding system...
Created on: 23 Sep 2014 22:16
E
ExoticHello everyone,
I recently registered here. At the moment, I’m a bit confused about equipotential bonding... We are building a house with a prefabricated basement, and the work should start as soon as possible. Last week, the basement contractor told me that equipotential bonding must be installed. However, I don’t fully understand what that entails. Do I need a ring earth electrode or a foundation earth electrode, or are they actually the same thing? Unfortunately, I’m not a professional and have never dealt with this before. I would appreciate any answers.
I should also add that the floor slab will be made of watertight concrete (WU concrete).
Best regards
I recently registered here. At the moment, I’m a bit confused about equipotential bonding... We are building a house with a prefabricated basement, and the work should start as soon as possible. Last week, the basement contractor told me that equipotential bonding must be installed. However, I don’t fully understand what that entails. Do I need a ring earth electrode or a foundation earth electrode, or are they actually the same thing? Unfortunately, I’m not a professional and have never dealt with this before. I would appreciate any answers.
I should also add that the floor slab will be made of watertight concrete (WU concrete).
Best regards
D
Doc.Schnaggls24 Sep 2014 08:02Hello,
I can’t say for sure if that is the same thing.
Our precast basement made of waterproof concrete (WU concrete) has definitely been equipped with a ring earth electrode, the end of which now emerges from the floor under the future fuse box in the basement.
Regards,
Dirk
I can’t say for sure if that is the same thing.
Our precast basement made of waterproof concrete (WU concrete) has definitely been equipped with a ring earth electrode, the end of which now emerges from the floor under the future fuse box in the basement.
Regards,
Dirk
B
Bauexperte24 Sep 2014 12:03Hello,
Equipotential bonding refers to measures taken to reduce or eliminate potential differences, i.e., electrical voltage differences between conductive pipe systems such as water, gas, or heating pipes, or between pipe systems and the protective conductor. To achieve this, the conductive pipe systems are connected by what is called an equipotential bonding conductor.
Such equipotential bonding is required for every newly installed electrical consumer system, and according to DIN VDE 100, Part 410 and following, a distinction is made between main equipotential bonding and additional local equipotential bonding.
The building’s technical installations consist, besides the electrical wiring, of more or less extensive piping systems for heating, gas, and water supply, which together form a complex network of conductive systems throughout the building. These pipe systems are sometimes interconnected but often separated from each other. Therefore, faults or defects in one system can adversely affect another system. For example, if an insulation fault occurs in the electrical system causing a metallic pipe to come into contact with a live conductor, a dangerous touch voltage can arise. This is shown schematically in Figure 1, where it can be seen that a touch voltage appears between pipe system 1 and pipe system 2, which a person could bridge. To largely avoid this hazardous condition, regulations require all metal systems to be electrically connected. Then no voltage differences, or potential differences as experts call them, and thus no dangerous touch voltages, can occur. This is called "equipotential bonding," and the conductor that connects the system parts is called the "equipotential bonding conductor."
The DIN VDE standard for low-voltage electrical installations requires equipotential bonding at every building service entrance or main distribution board. This is called the main equipotential bonding, and all metal pipe systems in the building, the main protective conductor of the electrical network, the main earthing conductor, as well as any other existing grounding and piping systems including antenna, telephone, or lightning protection systems, must be interconnected. All these conductors are connected via the main equipotential bonding conductor at the main equipotential bonding busbar. This busbar is connected via a terminal lug to the foundation earth electrode. Such a foundation earth electrode is mandatory because water supply systems often use plastic pipes that cannot serve as earth electrodes. However, it is not necessary to provide each pipe system with its own equipotential bonding conductor. Multiple systems can be connected with one another and connected via a common main equipotential bonding conductor. Main equipotential bonding conductors may be continuously marked green-yellow like protective conductors, but this is not mandatory; the conductors can also be bare or installed in any other color. At connection points, however, a permanent green-yellow marking must be present. For special electrical installations, such as those in medical applications, continuous green-yellow marking is required. The dimensioning of the main equipotential bonding conductor is determined by the cross-section of the main protective conductor of the installation; it must be at least half the cross-section of the largest protective conductor in the installation. The minimum cross-section is 6 mm2 Cu (6 mm2 (0.01 in2) copper), with an upper limit of 25 mm2 Cu (25 mm2 (0.04 in2) copper) or an equivalent conductor—these values are summarized in Table 1. The largest protective conductor in this context is the protective conductor leaving the main distribution board with the largest cross-section. Metallic pipelines can be included in the equipotential bonding, for example, over partial lengths, if they meet the requirements for equipotential bonding conductors. Attention must be paid here—for example, in threaded water pipes—that the transition resistance of threaded connections is not too high. However, no exact resistance value is specified, so the assessment is left to the installer’s experience and discretion. It may be helpful to compare with the resistance of an equivalent copper conductor. It must be known that internal gas pipes must not be used as equipotential bonding conductors. The reason is that, in case of fault currents, dangerous heat generation can occur at resistance-prone connections due to current flow. Leakage at the connections or worse can be the consequence. The gas pipe itself, however, must be included in the main equipotential bonding.
In areas with increased risk due to environmental conditions (e.g., moisture), an additional local equipotential bonding is required. This supplements the main equipotential bonding and prevents dangerous touch voltages. This is required, among other areas, in rooms with bathtubs or showers—specifically in zones 1, 2, and 3—as well as covered swimming pools. Metallic parts such as pipes and drain fittings at baths and showers must be connected by an equipotential bonding conductor with a minimum cross-section of 4 mm2 Cu (4 mm2 (0.006 in2) copper) and connected to the protective conductor. Galvanized steel strap with a minimum dimension of 20 mm x 2.5 mm (0.8 in x 0.1 in) is also permitted; however, copper conductors are preferred in practice for ease of installation.
The connection to the protective conductor can be made at a central point in the electrical system, such as the circuit distribution board, the main equipotential bonding busbar, or even at the water supply pipe if it is continuously conductive and connected to the main equipotential bonding. In medical rooms, an additional special equipotential bonding must also be carried out, as well as in areas where uncontrolled stray or equalizing currents could cause explosion hazards. The additional equipotential bonding must be installed even if there are no electrical devices present in the respective rooms. The reason is that dangerous touch voltages could be introduced into these rooms via conductive pipe systems.
After installation is complete but before energizing the electrical system, the effectiveness of the equipotential bonding must be tested. This involves first inspecting the main equipotential bonding to verify that all main equipotential bonding conductors, protective conductors, earth electrodes, metallic pipes, and building structures are connected conductively to the equipotential bonding busbar as required. All components of the equipotential bonding must be protected from damage and all connections must provide good and permanent contact. The same applies to the additional equipotential bonding, where it must be confirmed that all simultaneously accessible metallic parts, protective conductor connections, and other conductive bodies are interconnected.
Furthermore, the continuity resistance of these conductive connections must be measured. As shown in Figure 5, the resistance between the equipotential bonding busbar and the ends of the pipe sections included in the equipotential bonding is measured. The equipotential bonding is considered effective if a resistance of no more than 3 Ω (Ohm) is measured at a test current of at least 5 A (Ampere). From a safety perspective, a lower value, e.g., 1 Ω, is recommended in practice. The measurement is simplified by using an equipotential bonding tester, which is commercially available.
Best regards, Bauexperte
Exotic schrieb:Google would have been helpful here, as usual
Unfortunately, I am not a professional and have never dealt with this before.
Equipotential bonding refers to measures taken to reduce or eliminate potential differences, i.e., electrical voltage differences between conductive pipe systems such as water, gas, or heating pipes, or between pipe systems and the protective conductor. To achieve this, the conductive pipe systems are connected by what is called an equipotential bonding conductor.
Such equipotential bonding is required for every newly installed electrical consumer system, and according to DIN VDE 100, Part 410 and following, a distinction is made between main equipotential bonding and additional local equipotential bonding.
The building’s technical installations consist, besides the electrical wiring, of more or less extensive piping systems for heating, gas, and water supply, which together form a complex network of conductive systems throughout the building. These pipe systems are sometimes interconnected but often separated from each other. Therefore, faults or defects in one system can adversely affect another system. For example, if an insulation fault occurs in the electrical system causing a metallic pipe to come into contact with a live conductor, a dangerous touch voltage can arise. This is shown schematically in Figure 1, where it can be seen that a touch voltage appears between pipe system 1 and pipe system 2, which a person could bridge. To largely avoid this hazardous condition, regulations require all metal systems to be electrically connected. Then no voltage differences, or potential differences as experts call them, and thus no dangerous touch voltages, can occur. This is called "equipotential bonding," and the conductor that connects the system parts is called the "equipotential bonding conductor."
The DIN VDE standard for low-voltage electrical installations requires equipotential bonding at every building service entrance or main distribution board. This is called the main equipotential bonding, and all metal pipe systems in the building, the main protective conductor of the electrical network, the main earthing conductor, as well as any other existing grounding and piping systems including antenna, telephone, or lightning protection systems, must be interconnected. All these conductors are connected via the main equipotential bonding conductor at the main equipotential bonding busbar. This busbar is connected via a terminal lug to the foundation earth electrode. Such a foundation earth electrode is mandatory because water supply systems often use plastic pipes that cannot serve as earth electrodes. However, it is not necessary to provide each pipe system with its own equipotential bonding conductor. Multiple systems can be connected with one another and connected via a common main equipotential bonding conductor. Main equipotential bonding conductors may be continuously marked green-yellow like protective conductors, but this is not mandatory; the conductors can also be bare or installed in any other color. At connection points, however, a permanent green-yellow marking must be present. For special electrical installations, such as those in medical applications, continuous green-yellow marking is required. The dimensioning of the main equipotential bonding conductor is determined by the cross-section of the main protective conductor of the installation; it must be at least half the cross-section of the largest protective conductor in the installation. The minimum cross-section is 6 mm2 Cu (6 mm2 (0.01 in2) copper), with an upper limit of 25 mm2 Cu (25 mm2 (0.04 in2) copper) or an equivalent conductor—these values are summarized in Table 1. The largest protective conductor in this context is the protective conductor leaving the main distribution board with the largest cross-section. Metallic pipelines can be included in the equipotential bonding, for example, over partial lengths, if they meet the requirements for equipotential bonding conductors. Attention must be paid here—for example, in threaded water pipes—that the transition resistance of threaded connections is not too high. However, no exact resistance value is specified, so the assessment is left to the installer’s experience and discretion. It may be helpful to compare with the resistance of an equivalent copper conductor. It must be known that internal gas pipes must not be used as equipotential bonding conductors. The reason is that, in case of fault currents, dangerous heat generation can occur at resistance-prone connections due to current flow. Leakage at the connections or worse can be the consequence. The gas pipe itself, however, must be included in the main equipotential bonding.
In areas with increased risk due to environmental conditions (e.g., moisture), an additional local equipotential bonding is required. This supplements the main equipotential bonding and prevents dangerous touch voltages. This is required, among other areas, in rooms with bathtubs or showers—specifically in zones 1, 2, and 3—as well as covered swimming pools. Metallic parts such as pipes and drain fittings at baths and showers must be connected by an equipotential bonding conductor with a minimum cross-section of 4 mm2 Cu (4 mm2 (0.006 in2) copper) and connected to the protective conductor. Galvanized steel strap with a minimum dimension of 20 mm x 2.5 mm (0.8 in x 0.1 in) is also permitted; however, copper conductors are preferred in practice for ease of installation.
The connection to the protective conductor can be made at a central point in the electrical system, such as the circuit distribution board, the main equipotential bonding busbar, or even at the water supply pipe if it is continuously conductive and connected to the main equipotential bonding. In medical rooms, an additional special equipotential bonding must also be carried out, as well as in areas where uncontrolled stray or equalizing currents could cause explosion hazards. The additional equipotential bonding must be installed even if there are no electrical devices present in the respective rooms. The reason is that dangerous touch voltages could be introduced into these rooms via conductive pipe systems.
After installation is complete but before energizing the electrical system, the effectiveness of the equipotential bonding must be tested. This involves first inspecting the main equipotential bonding to verify that all main equipotential bonding conductors, protective conductors, earth electrodes, metallic pipes, and building structures are connected conductively to the equipotential bonding busbar as required. All components of the equipotential bonding must be protected from damage and all connections must provide good and permanent contact. The same applies to the additional equipotential bonding, where it must be confirmed that all simultaneously accessible metallic parts, protective conductor connections, and other conductive bodies are interconnected.
Furthermore, the continuity resistance of these conductive connections must be measured. As shown in Figure 5, the resistance between the equipotential bonding busbar and the ends of the pipe sections included in the equipotential bonding is measured. The equipotential bonding is considered effective if a resistance of no more than 3 Ω (Ohm) is measured at a test current of at least 5 A (Ampere). From a safety perspective, a lower value, e.g., 1 Ω, is recommended in practice. The measurement is simplified by using an equipotential bonding tester, which is commercially available.
Best regards, Bauexperte
Bauexperte schrieb:
Aunt Google could have been helpful - as always As can unfortunately be seen from many links, Google does not forget even outdated, normatively obsolete old posts.The quoted article by Ing. Günter E. Wegner in IKZ-HAUSTECHNIK, issue 8/1998, page 88 ff., was already a proud 16 years old at the time of the link in 2014 and only partially correct anymore. The passage
[QUOTE=]Metal parts such as pipes, drain nozzles on bathtubs and shower trays must be connected via an equipotential bonding conductor – with a minimum cross-section of 4 mm² Cu – and connected to the protective conductor.[/QUOTE]
was formulated incorrectly from the beginning.
That outdated publications cannot include the current technical terms, such as protective equipotential bonding or main earthing terminal, is not a major issue, as is when builders are led to bathtub earthing, which is no longer required in buildings with protective equipotential bonding.
In a housebuilding forum, links to publications should at least refer to the current state of the recognized rules of technology or the state of the art. However, in 2014 not only indoor gas pipes as equipotential bonding conductors (or antenna earthing conductors) were prohibited. That the article confuses units of resistance with watts and ohms and the error was adopted without comment is simply a cause for a smile.
For questions about lightning protection, grounding, and equipotential bonding, the DEHN Lightning Planner and the information from H. Kleiske are much more up to date with current standards.
It is surprising that the outdated statements have remained unchallenged for so long.
Exotic schrieb:
Do I need a ring earth electrode or a foundation earth electrode, or are they basically the same? I am not an expert and have never dealt with this before. I would appreciate any answers.
Best regardsAfter all the (very interesting) technical explanations above, I wanted to briefly address the question.
No, a ring earth electrode and a foundation earth electrode are not the same.
Please consult with the qualified electrician who will carry out the equipotential bonding at your site to see what they recommend. The electrician must also perform the acceptance test afterward. Without this (successfully passed, of course!), you will not receive an electricity connection from the utility provider.
Personally, I consider the (more expensive) ring earth electrode better or more appropriate for a basement. It is even possible (some people do) to install both.
Although I have a house without a basement, for safety and durability reasons I decided to opt for the ring earth electrode.
Best regards
Thorsten
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