Just to clarify and rehash previous comments that amused a few readers:
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Here we have a conductive component and an insulating component - that is a capacitor. Bonding the metal pipes will eliminate capactively coupled voltage on those pipes as referenced to the pool/spa.
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To drain a capacitor all you need to do is short the two plates together. Permanently short them together and you don't have a capacitor anymore.
---I guess my point all along is bonding turns what was a natural capacitor into a non capacitor. All metallic components will remain at same potential. They may change potential in relation to something not bonded. This is what equipotential bonding is all about though, everything bonded is at same potential.
Yes, it all should be at the same or very close potential. But you raised an interesting point...that the decking could in effect create a capacitor, which is a storage rather than conductive medium. Bonding the pipes would not necessarily drain the charge, and could actually work to charge the capacitor instead. It's all very undefinable and mostly theoretical. I'm no dirt worshipper by any means, but do think the pipes should be bonded in this instance.
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Equipotential bonding isn't about draining the charge, and it isn't about additional "grounding/earthing" - it is about putting everything you do bond at the same potential.
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Bonding those pipes to the tub just increases the size of the capacitor plate.
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That said the tub is still supposed to get connected to an EGC nearly every case so that will end up draining the capacitor anyway.
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I understand equipotential bonding. I was expanding upon your theory of capacitance in an object such as a treated wood deck structure. The point being that IF a wooden deck is capable of holding a capacitive charge, there must be something to charge it. A voltage gradient imposed on the rest of the equipotential bonding system could charge it. It wouldn't be able to store a voltage higher than that of the equipotential system, so would present no danger. An intermittently poor connection with the equipotential system could pose a dangerous difference in potential, and as there is no method of bonding metal to wood with any certainty, a varying potential within the equipotential system coupled with an intermittent bond between the pipes and deck could leave the deck (our theoretical large capacitor) at a higher potential than the rest of the system. I think that's where Dennis was going with this.
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Was brought up what would energize isolated metal components - capacitance was just one possibility even if not all that likely.
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One can ask similar question about something like metal structure for a diving platform, lifeguard stand, slide support structure, and similar things around a swimming pool - what is going to energize them? Answer is it is probably not all that likely, but we bond them anyway because we don't want them somehow (though unknown how) they will become at different potential then the pool, deck etc.”
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My comment:
At consumer level 120/240 VAC power supply with the (possible) potential build up in household wiring system that is introduced by capacitance is so miniscule that humans should not even be concerned.
It is expressed in microfarads generally- - - save for very high voltage ranging in KV.
Another point that seems (as demonstrated by several posts above) is the erroneous assertion that capacitance could result-- and thereby cause harm associated with AC power system.
Energy build up in DC through capacitive energy is different from AC. While it is possible to charge a capacitor with DC and therefore utilize the charge for some electronics circuitry, it is not readily achievable from a garden variety perspective-- and can cause fatal shock when powered from AC.
When DC is applied to a capacitor, it acts like a battery and it holds its charge until it is discharged by either using the charge or simply dumping it.
In AC, the capacitor will only charge at the half sine wave when it is at its positive region, but will discharge as soon as the sine wave starts its negative transition. This happens so many times depending on the frequency.
It's because of this phenomenon that makes AC's accumulated capacitance should not be a concern. It dissipates naturally.
So, relax about this notion that capacitance will occur on the piece of pipe, and the capacitance of the wood deck that leads to the
false creation of capacitor plate.
It is a myth that one needs to be careful propagating erroneously.
The big concern (very likely) is the build up of electrostatic charge of the metal pipe that is being isolated from whatever path of potential to ground (earth).
Perhaps the inspector is concerned about the accumulation of static charge in the metal pipe. This is the logic that prompted his bonding/grounding exigency . He is right and not being totalitarian as one poster had assumed.
The inspector's assertion is reasonable. . . that's why he is inspector and the poster is not.
I'm not saying that they are always right, but in this instance I agree with him.
Static charge that could go as high as 50 KV or more, is harmful to electronic life-saving gadgetry like
pacemakers. A person wearing a PM and unintentionally exposing himself to release of this electrostatic charge could suffer arrhythmia.
It could also fry your iPad for sure.
Not to mention cell phones and other sensitive audio equipment.
